Communication system, communication device, control method, and program

Abstract

To reduce interference from radio waves in wireless communication. [Solution] The transport trolley 10 includes a first control unit that (a) stores the first data contained in the first specific field of the first frame received by the communication unit 122 in the storage unit 124 if the first data is not stored in the storage unit 124, and causes the first frame to be transmitted by the wireless communication unit 121, and (b) deletes the first specific field from the first frame and transmits it if the first data is stored in the storage unit 124. The communication device 22 includes a second control unit that (c) stores the first data contained in the first specific field in the storage unit 224 if the second frame received by the wireless communication unit 221 contains the first specific field, and causes the second frame to be transmitted by the communication unit 222, and (d) generates a first specific field containing the first data stored in the storage unit 224 and adds it to the second frame and transmits it if the second frame does not contain the first specific field.

Description

Technical Field

[0001] The present invention relates to a communication system, a communication device, a control method, and a program.

Background Art

[0002] It is known that the performance of wireless communication deteriorates due to interference of radio waves of wireless communication.

[0003] For example, there is control wireless communication in which a control server controls a carrier cart. For communication between the control server and the carrier cart, communication with a fixed cycle and low latency is required. When the control server and the carrier cart do not have a wireless communication interface, a wireless communication device (also referred to as a server-side wireless communication device) connected to the control server by wire and a wireless communication device (also referred to as a cart-side wireless communication device) connected to the carrier cart by wire can be used.

[0004] Specifically, the control server transmits command data to a carrier cart to be controlled by wireless communication via the server-side wireless communication device. The carrier cart receives the command data by wireless communication via the cart-side wireless communication device. The carrier cart that has received the command data creates response data and transmits the response data to the control server by wireless communication via the cart-side wireless communication device. The control server receives the response data by wireless communication via the server-side wireless communication device.

[0005] In such a case, in communication between the control server and the carrier cart, the performance of wireless communication may deteriorate due to radio wave interference. When the performance of wireless communication deteriorates, the control of the carrier cart by the control server may be hindered.

[0006] As another example, there is interlock communication between a carrier cart that periodically transmits and receives data (for example, I / O data) by Peer to Peer and a manufacturing apparatus (for example, a semiconductor manufacturing apparatus). For transmission and reception of I / O data, communication with a fixed cycle and bidirectional is required.

[0007] If the manufacturing equipment does not have a wireless communication interface, a wireless communication device (also called the manufacturing equipment-side wireless communication device) connected to the manufacturing equipment by a wire may be used for interlock communication. The transport cart transmits data to the manufacturing equipment wirelessly via the cart-side wireless communication device. The manufacturing equipment receives the data wirelessly via the manufacturing equipment-side wireless communication device.

[0008] In such cases, if radio interference degrades the performance of wireless communication between the transport cart and the manufacturing equipment, it may become impossible to perform interlock communication properly.

[0009] Patent Document 1 discloses technology relating to a wireless communication device that can suppress performance degradation caused by radio wave interference. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Patent No. 3607632 [Overview of the project] [Problems that the invention aims to solve]

[0011] As described above, there is a problem in communication between a control server and a transport cart using wireless communication, or between a transport cart and manufacturing equipment, where interference from wireless communication radio waves may degrade the performance of the wireless communication.

[0012] The present invention aims to provide a communication system that reduces interference from radio waves in wireless communication. [Means for solving the problem]

[0013] The following describes examples of inventions that can be obtained from the disclosures in this specification, and explains the effects and other benefits that can be obtained from such inventions.

[0014] (1) A communication system comprising a first communication device connected to a first device and a second communication device connected to a second device, wherein the first communication device includes a first communication unit that receives a first frame from the first device, a first storage unit, a second communication unit that transmits a second frame to the second device by wireless communication, and a first control unit, wherein (a) if the first data contained in a first specific field of the first frame received by the first communication unit is not stored in the first storage unit, the first data is stored in the first storage unit and the first frame is transmitted as a second frame by the second communication unit, and (b) if the first data contained in the first specific field of the first frame received by the first communication unit is stored in the first storage unit, the first specific field is deleted from the first frame and the first frame from which the first specific field has been deleted is transmitted as a second frame by the second communication unit A communication system comprising: a first control unit which transmits as a frame; a second communication device which comprises: a third communication unit which receives the second frame from the first communication device via wireless communication; a second storage unit which transmits the third frame to the second device; and a second control unit which (c) if the second frame received by the third communication unit includes the first specific field, stores the first data included in the first specific field in the second storage unit and causes the second frame to be transmitted as the third frame by the fourth communication unit; and (d) if the second frame received by the third communication unit does not include the first specific field, generates the first specific field which includes the first data stored in the second storage unit and adds it to the second frame, and causes the second frame with the first specific field added to be transmitted as the third frame by the fourth communication unit.

[0015] According to the above embodiment, the first communication device may transmit a second frame in which the first specific field has been deleted, and the second communication device can perform the same subsequent processing as when it receives the second frame in which the first specific field has been deleted, even if it receives the second frame in which the first specific field has been deleted. As a result, the communication system may transmit and receive a second frame in which the first specific field has been deleted in the wireless communication section from the first communication device to the second communication device, thereby reducing the time that occupies the transmission of radio waves for wireless communication, and contributing to the reduction of interference of radio waves for wireless communication (in other words, reducing the opportunities for radio wave interference to occur). Therefore, the communication system can reduce interference of radio waves for wireless communication.

[0016] (2) The fourth communication unit further receives the fourth frame transmitted by the second device after it has received the third frame, the third communication unit further transmits the fifth frame to the first communication device via wireless communication, and the second control unit further (e) if the second data contained in the second specific field of the fourth frame received by the fourth communication unit is not stored in the second storage unit, stores the second data in the second storage unit and causes the third communication unit to transmit the fourth frame as the fifth frame, and (f) if the second data contained in the second specific field of the fourth frame received by the fourth communication unit is stored in the second storage unit, deletes the second specific field from the fourth frame and causes the third communication unit to transmit the fourth frame from which the second specific field has been deleted as the fifth frame. The communication system according to (1), wherein the second communication unit further receives the fifth frame from the second communication device via wireless communication, the first communication unit further transmits the sixth frame to the first communication device, and the first control unit further (g) if the fifth frame received by the second communication unit includes the second specific field, stores the second data included in the second specific field in the first storage unit and causes the first communication unit to transmit the fifth frame as the sixth frame, and (h) if the fifth frame received by the second communication unit does not include the second specific field, generates the second specific field including the second data stored in the first storage unit and adds it to the fifth frame, and causes the first communication unit to transmit the fifth frame with the second specific field added as the sixth frame.

[0017] According to the above embodiment, the second communication device may transmit a fifth frame in which the second specific field has been deleted, and the first communication device can perform the same subsequent processing as when it receives a fifth frame in which the second specific field has been deleted. As a result, the communication system may transmit and receive fifth frames in which the second specific field has been deleted in the wireless communication section from the second communication device to the first communication device, thereby reducing the time required to transmit wireless radio waves and contributing to the reduction of interference between wireless radio waves. Therefore, the communication system can reduce interference between wireless radio waves.

[0018] (3) The communication system according to (1) or (2), wherein the first specific field includes, as first data, information indicating the state of the first device.

[0019] According to the above embodiment, the communication system can contribute to reducing interference of radio waves in wireless communication by using information indicating the state of a first device as first data of a first specific field.

[0020] (4) The communication system according to (2), wherein the second specific field includes information indicating the state of the second device as the second data.

[0021] According to the above embodiment, the communication system can contribute to reducing interference of radio waves in wireless communication by using information indicating the state of a second device as second data of a second specific field.

[0022] (5) The first specific field includes, as the first data, command data including instructions from the first device to the second device, the first frame further includes a first sequence number assigned by the first device, the second frame further includes a first sequence number, and when the first control unit stores the first data included in the first specific field of the first frame in the first storage unit, it stores the first sequence number included in the first frame in association with the command data, and further, when the first specific field is deleted from the first frame, the first sequence number included in the first frame The communication system according to (1) or (2), wherein the number is changed to the first sequence number stored in the first storage unit in association with the command data, and when the second control unit stores the first data contained in the first specific field in the second storage unit, it stores the first sequence number contained in the second frame in association with the command data, and further, when generating the first specific field and adding it to the second frame, it generates the first specific field containing the command data stored in the second storage unit in association with the first sequence number contained in the second frame and adds it to the second frame.

[0023] According to the above embodiment, the communication system can contribute to reducing interference of radio waves in wireless communication by using command data, which includes instructions from a first device to a second device, as first data of a first specific field.

[0024] (6) The second specific field includes, as the second data, response data including a response from the second device to the first device. The fourth frame further includes a second sequence number assigned by the second device. The fifth frame further includes a second sequence number. When the second control unit stores the second data included in the second specific field of the fourth frame in the second storage unit, the second control unit stores the second sequence number included in the fourth frame in the second storage unit in association with the response data. Further, when the second specific field is deleted from the fourth frame, the second control unit changes the second sequence number included in the fourth frame to the second sequence number stored in the second storage unit in association with the second sequence number. When the first control unit stores the second data included in the second specific field in the first storage unit, the first control unit stores the second sequence number included in the fifth frame in the first storage unit in association with the response data. Further, when generating and adding the second specific field to the second frame, the first control unit generates the second specific field including the response data stored in the second storage unit in association with the second sequence number included in the second frame and adds the second specific field to the second frame. The communication system according to (2).

[0025] According to the above aspect, the communication system can contribute to reducing interference of radio waves in wireless communication by using, as the second data of the second specific field, response data including a response from the second device to the first device.

[0026] A communication device which is a first communication device wirelessly connected to a second communication device connected to a first device, the communication device comprising: a first communication unit that receives a first frame from the first device; a first storage unit; a second communication unit that transmits a second frame to the second device by wireless communication; and a first control unit, wherein: (a) when first data included in a first specific field of the first frame received by the first communication unit is not stored in the first storage unit, the first data is stored in the first storage unit and the first frame is transmitted as the second frame by the second communication unit; and (b) when the first data included in the first specific field of the first frame received by the first communication unit is stored in the first storage unit, the first specific field is deleted from the first frame and the first frame with the first specific field deleted is transmitted as the second frame by the second communication unit.

[0027] According to the above aspect, the first communication device may transmit a second frame with the first specific field deleted. Thereby, since the first communication device may transmit a second frame with the first specific field deleted in the wireless communication section from the first communication device to the second communication device, the time occupied by the transmission of the radio wave of the wireless communication can be reduced, which can contribute to the reduction of the interference of the radio wave of the wireless communication. Therefore, the communication device which is the first communication device can reduce the interference of the radio wave of the wireless communication.

[0028] (8) A communication device which is a second communication device connected to a second device and connected wirelessly to a first communication device connected to a first device, comprising: a third communication unit that receives a second frame from the first communication device by wireless communication; a second storage unit; a fourth communication unit that transmits the third frame to the second device; and a second control unit which (c) if the second frame received by the third communication unit includes a first specific field, stores the first data included in the first specific field in the second storage unit and causes the second frame to be transmitted by the fourth communication unit as the third frame; and (d) if the second frame received by the third communication unit does not include the first specific field, generates the first specific field including the first data stored in the second storage unit and adds it to the second frame, and causes the second frame with the first specific field added to be transmitted as the third frame; and the second control unit.

[0029] According to the above embodiment, even when the second communication device receives a second frame transmitted by the first communication device in which the first specific field has been deleted, it can perform the same subsequent processing as when it receives a second frame containing the first specific field. As a result, since the second communication device may receive a second frame in which the first specific field has been deleted, the time it occupies in transmitting radio waves for wireless communication can be reduced, which can contribute to reducing interference with radio waves for wireless communication. Therefore, the communication system can reduce interference with radio waves for wireless communication.

[0030] (9) A control method to be performed by a communication system comprising a first communication device connected to a first device and a second communication device connected to a second device, wherein the first communication device comprises a first communication unit that receives a first frame from the first device, a first storage unit, a second communication unit that transmits a second frame to the second device by wireless communication, and a first control unit, and the second communication device comprises a third communication unit that receives the second frame from the first communication device by wireless communication, a second storage unit, a fourth communication unit that transmits a third frame to the second device, and a second control unit, and the control method comprises (a) the first control unit storing the first data contained in a first specific field of the first frame received by the first communication unit in the first storage unit if the first data is not stored in the first storage unit, and causing the second communication unit to transmit the first frame as the second frame, and (b) the first control unit A control method comprising: (c) if the first data contained in the first specific field of the frame is stored in the first storage unit, the first specific field is deleted from the first frame, and the second communication unit transmits the first frame from which the first specific field has been deleted as the second frame; (d) if the second frame received by the third communication unit contains the first specific field, the second control unit stores the first data contained in the first specific field in the second storage unit and has the fourth communication unit transmit the second frame as the third frame; and (e) if the second frame received by the third communication unit does not contain the first specific field, the second control unit generates a first specific field containing the first data stored in the second storage unit and adds it to the second frame, and has the second frame with the first specific field added transmit as the third frame.

[0031] According to the above embodiment, the same effects as the above communication system are achieved.

[0032] (10) A control method for a communication device which is a first communication device connected to a first device and connected wirelessly to a second communication device which is connected to a second device, comprising: a first communication unit that receives a first frame from the first device; a first storage unit; a second communication unit that transmits a second frame to the second device wirelessly; and a first control unit, wherein the first control unit (a) stores the first data contained in a first specific field of the first frame received by the first communication unit in the first storage unit if the first data is not stored in the first storage unit, and causes the second communication unit to transmit the first frame as the second frame; and (b) deletes the first specific field from the first frame and causes the second communication unit to transmit the first frame from which the first specific field has been deleted as the second frame if the first data contained in a first specific field of the first frame received by the first communication unit is stored in the first storage unit.

[0033] According to the above embodiment, the same effects as the first communication device described above are achieved.

[0034] (11) A control method for a communication device which is a second communication device connected to a second device and also connected wirelessly to a first communication device connected to a first device, comprising: a third communication unit that receives a second frame from the first communication device by wireless communication; a second storage unit; a fourth communication unit that transmits the third frame to the second device; and a second control unit, wherein the second control unit (c) stores first data contained in the first specific field in the second storage unit and causes the fourth communication unit to transmit the second frame as the third frame if the second frame received by the third communication unit includes a first specific field; and (d) generates a first specific field containing the first data stored in the second storage unit and adds it to the second frame, and causes the second frame with the first specific field added to transmit as the third frame.

[0035] According to the above embodiment, the same effects as those of the second communication device described above are achieved.

[0036] (12) A program that causes a computer to execute the control method described in (10).

[0037] According to the above embodiment, the same effects as the first communication device described above are achieved.

[0038] (13) A program that causes a computer to execute the control methods described in (11).

[0039] According to the above embodiment, the same effects as those of the second communication device described above are achieved.

[0040] Furthermore, the present invention can be implemented not only as a device, but also as a method in which the processing means constituting the device are steps, as a program that causes a computer to execute those steps, as a recording medium such as a computer-readable CD-ROM on which the program is recorded, or as information, data, or signals that represent the program. These programs, information, data, and signals may be distributed via a communication network such as the Internet. [Effects of the Invention]

[0041] The present invention makes it possible to reduce interference between radio waves in wireless communication systems. [Brief explanation of the drawing]

[0042] [Figure 1] This is a schematic diagram showing the configuration of a communication system according to an embodiment. [Figure 2] This is a block diagram showing a first example of the functional configuration of a communication system according to an embodiment. [Figure 3] This is a flowchart showing a first example of the processing of a communication device according to the embodiment. [Figure 4] This is an explanatory diagram showing a first example of a frame configuration according to an embodiment. [Figure 5] This is an explanatory diagram showing a second example of the frame configuration according to the embodiment. [Figure 6] This is a flowchart showing a second example of the processing of the communication device according to the embodiment. [Figure 7] This is a sequence diagram showing a first example of the processing of the communication system according to the embodiment. [Figure 8] This is a sequence diagram showing a second example of the processing of the communication system according to the embodiment. [Figure 9] This is a sequence diagram showing a third example of the processing of the communication system according to the embodiment. [Figure 10] This is a block diagram showing a second example of the functional configuration of a communication system according to an embodiment. [Figure 11] This is a flowchart showing a third example of the processing of a communication device according to the embodiment. [Figure 12] This is an explanatory diagram showing a third example of the frame configuration according to the embodiment. [Figure 13] This is an explanatory diagram showing a fourth example of the frame configuration according to the embodiment. [Figure 14] This is a flowchart showing a fourth example of the processing of the communication device according to the embodiment. [Figure 15] This is a sequence diagram showing a first example of the processing of the communication system according to the embodiment. [Figure 16] This is a sequence diagram showing a second example of the processing of the communication system according to the embodiment. [Figure 17] This is a sequence diagram showing a third example of the processing of the communication system according to the embodiment. [Modes for carrying out the invention]

[0043] The embodiments will be described in detail below with reference to the drawings.

[0044] The embodiments described below all represent preferred specific examples of the present invention. The numerical values, shapes, materials, components, arrangement and connection configurations of components, steps, and the order of steps shown in the following embodiments are examples only and are not intended to limit the present invention. Furthermore, among the components in the following embodiments, those components that are not described in the independent claims representing the highest-level concept of the present invention are described as any components that constitute a more preferred form. Note that identical components may be denoted by the same reference numeral and their descriptions may be omitted.

[0045] (Embodiment) In this embodiment, a communication system for reducing interference from radio waves in wireless communication will be described.

[0046] Figure 1 is a schematic diagram showing the configuration of the communication system 1 according to this embodiment.

[0047] As shown in Figure 1, the communication system 1 comprises a transport cart 10, a manufacturing device 20, and a control server 30.

[0048] Communication system 1 is installed in facilities such as semiconductor factories and is a transport system that transports goods 5 using a transport cart 10. It is a system that performs SEMI standard E84 interlock communication (also simply called interlock communication) for the transfer of goods 5 between the transport cart 10 and the manufacturing equipment 20. In this system, the above SEMI standard E84 interlock communication is performed wirelessly, and more specifically, by storing parallel I / O signals (8 bits) from the transport cart 10 side and parallel I / O signals (8 bits) from the manufacturing equipment 20 side in a communication frame (also simply called a frame) and transmitting and receiving them wirelessly.

[0049] The communication system 1 may include one or more transport carts 10, and one or more manufacturing devices 20. Furthermore, there may be one or more articles 5. Here, we will focus on a pair of transport carts 10 and manufacturing devices 20 used for the transfer of one article 5.

[0050] The transport cart 10 is a transport cart that moves along the track 7 and transports the goods 5. The transport cart 10 can exchange the goods 5 with the manufacturing equipment 20 while performing interlock communication with the communication device 22 provided by the manufacturing equipment 20.

[0051] Track 7 is a track permanently installed in the facility and serves as the travel path for the transport trolley 10. Track 7 is installed, for example, on or near the ceiling of the facility. In this case, the movement of the transport trolley 10 along track 7 means that the transport trolley 10 moves suspended beneath track 7, and this is used as an example for explanation, but it is not limited to this. For example, if track 7 is installed on the floor, the movement of the transport trolley 10 along track 7 may mean moving along the track installed on the floor.

[0052] Multiple locations on the track 7 are provided with codes (e.g., barcodes or two-dimensional codes) indicating those locations. The transport cart 10 is equipped with an encoder, which allows it to measure the distance traveled after reading a code. The transport cart 10 can determine its own position on the track 7 using the codes provided on the track 7 and the encoder mounted on the transport cart 10. The transport cart 10 transfers the goods 5 between itself and the manufacturing equipment 20 at predetermined transfer positions on the track 7.

[0053] The manufacturing apparatus 20 is a manufacturing device installed in a facility (for example, a device that processes article 5). The manufacturing apparatus 20 is provided with a loading port for receiving article 5 from the transport cart 10 and for transferring article 5 to the transport cart 10. Article 5 can be placed on the loading port. The loading port is equipped with at least a loading sensor that can sense whether or not article 5 is placed on it, and information indicating whether or not article 5 is placed is obtained using the loading sensor.

[0054] The manufacturing apparatus 20 is equipped with a communication device 22. The communication device 22 is connected to a mounting port of the manufacturing apparatus 20 by a connector. The communication device 22 may be located on the side or top surface of the manufacturing apparatus 20. The communication device 22 can exchange goods 5 with the transport trolley 10 while maintaining interlock communication with the transport trolley 10.

[0055] The control server 30 is a computer that controls the overall operation of the transport cart 10 of the communication system 1. The control server 30 is connected to the transport cart 10 via various wireless communication methods to enable communication with it.

[0056] When the control server 30 moves the item 5 to the manufacturing device 20, it identifies the manufacturing device 20 to which the item 5 will be moved, and also identifies the transport cart 10 that will transport the item 5. The control server 30 then calculates the movement path that the transport cart 10 will take to move toward the manufacturing device 20. The control server 30 also controls the movement of the transport cart 10 along the calculated movement path and controls the transfer of the item 5 between the transport cart 10 and the manufacturing device 20.

[0057] The above facility is, for example, a semiconductor manufacturing plant. In this case, item 5 is, for example, a FOUP (Front Opening Unify Pod) containing a semiconductor wafer. The manufacturing equipment 20 is, for example, a semiconductor manufacturing device. The mounting port of the manufacturing equipment 20 is provided on the semiconductor manufacturing device and can receive the FOUP, which is item 5, from the transport cart 10, or transfer the FOUP, which is item 5, to the transport cart 10. The track 7 is, for example, installed on the ceiling of the semiconductor manufacturing plant. The transport cart 10 is an overhead transport cart that travels suspended below the track 7.

[0058] The communication between the transport cart 10 and the manufacturing equipment 20, as shown in Figure 1, and the communication between the control server 30 and the transport cart 10, utilize wireless communication in at least part of the process. Techniques for reducing radio wave interference in this wireless communication will be described below.

[0059] (1) Communication between the transport trolley 10 and the manufacturing equipment 20 Figure 2 is a block diagram showing a first example of the functional configuration of the communication system according to this embodiment. The communication system shown in Figure 2 is also referred to as communication system 2.

[0060] As shown in Figure 2, the communication system 2 comprises a transport cart 10, a manufacturing device 20, and a communication device 22. The communication device 22 is connected to the manufacturing device 20 and relays interlock communication data between the transport cart 10 and the manufacturing device 22.

[0061] The transport trolley 10 includes a control device 110 and a communication device 120.

[0062] The control device 110 comprises a communication unit 111, a control unit 112, and a storage unit 113. The control device 110 corresponds to the first device.

[0063] The communication unit 111 is connected to the communication device 120 and is a communication interface that enables communication between the control device 110 and the communication device 120. The communication standard of the communication unit 111 may be a wired communication standard or a wireless communication standard. The communication standard of the communication unit 111 may be, for example, a serial communication standard (e.g., RS-232C) or a wired LAN communication standard (e.g., IEEE802.3).

[0064] Furthermore, a communication interface, which is a communication standard for wired communication, includes connection terminals and signal converters, etc. Similarly, a communication interface, which is a communication standard for wireless communication, includes an antenna and RF (Radio Frequency) circuitry, etc. The same applies hereafter.

[0065] The control unit 112 controls the interlock communication between the transport trolley 10 and the manufacturing equipment 20. The control unit 112 can be implemented by a processor (e.g., a CPU (Central Processing Unit)).

[0066] The control unit 112 controls the communication unit 111 to perform interlock communication in synchronization with the manufacturing equipment 20 via the communication devices 120 and 22. Specifically, the control unit 112 controls the communication unit 111 to perform interlock communication when it determines that the position of the transport trolley 10 on the track 7 is a suitable position for interlock communication (for example, directly above or near the manufacturing equipment 20). As mentioned above, the position of the transport trolley 10 on the track 7 is the position determined by the transport trolley 10 itself using the code provided on the track 7 and the encoder mounted on the transport trolley 10.

[0067] The storage unit 113 is a storage device capable of storing data or information. Data can be stored in the storage unit 113 by the control unit 112. Furthermore, data stored in the storage unit 113 can be read out by the control unit 112.

[0068] The memory unit 113 may be a volatile memory device such as DRAM (Dynamic Random Access Memory), or a non-volatile memory device such as an HDD (Hard Disk Drive) or SSD (Solid State Drive).

[0069] The communication device 120 comprises a wireless communication unit 121, a communication unit 122, a control unit 123, and a storage unit 124. The communication device 120 corresponds to the first communication device.

[0070] The wireless communication unit 121 is connected to the communication device 22 and is a wireless communication interface that performs wireless communication between the communication device 120 and the communication device 22. The frame that the wireless communication unit 121 transmits to the communication device 22 corresponds to the second frame, and the frame that the wireless communication unit 121 receives from the communication device 22 corresponds to the fifth frame. The wireless communication unit 121 corresponds to the second communication unit.

[0071] The communication standard of the wireless communication unit 121 is a wireless communication standard, and may be, for example, a wireless LAN (Local Area Network) communication standard such as IEEE 802.11a, b, g, n, ac, or ax, or a proximity wireless communication standard such as BLE (Bluetooth Low Energy).

[0072] The communication unit 122 is connected to the control device 110 and is a communication interface that facilitates communication between the communication device 120 and the control device 110. The frame that the communication unit 122 receives from the control device 110 corresponds to the first frame, and the frame that the communication unit 122 transmits to the control device 110 corresponds to the sixth frame. The communication unit 122 corresponds to the first communication unit.

[0073] The communication standard of the communication unit 122 may be a wired communication standard or a wireless communication standard. The communication standard of the communication unit 122 may be, for example, a serial communication standard (e.g., RS-232C) or a wired LAN communication standard (e.g., IEEE802.3).

[0074] The control unit 123 controls the communication unit 122 to transmit frames received from the control device 110 to the communication device 22 via the wireless communication unit 121, and also controls the communication unit 122 to transmit frames received from the communication device 22 to the control device 110 via the wireless communication unit 121. The control unit 123 corresponds to the first control unit. The control unit 123 can be implemented by a processor (e.g., a CPU).

[0075] During the above control, the control unit 123 can store data contained in a predetermined field (also called a specific field) of the frame in the storage unit 124. The control unit 123 can also delete a specific field from a frame or add a specific field to a frame that does not have one.

[0076] Specifically, if the data (corresponding to the first data) contained in a specific field (corresponding to the first specific field) of the first frame received by the communication unit 122 is not stored in the storage unit 124, the control unit 123 stores the first data in the storage unit 124 and causes the first frame to be transmitted as the second frame by the wireless communication unit 121. Also, if the first data contained in the first specific field of the first frame received by the communication unit 122 is stored in the storage unit 124, the control unit 123 deletes the first specific field from the first frame and causes the first frame from which the first specific field has been deleted to be transmitted as the second frame by the wireless communication unit 121.

[0077] Furthermore, if the fifth frame received by the wireless communication unit 121 includes a second specific field, the control unit 123 may store the second data included in the second specific field in the storage unit 124 and have the communication unit 122 transmit the fifth frame as a sixth frame. Alternatively, if the fifth frame received by the wireless communication unit 121 does not include a second specific field, the control unit 123 may generate a second specific field including the second data stored in the storage unit 124 and add it to the fifth frame, and have the communication unit 122 transmit the fifth frame with the added second specific field as a sixth frame.

[0078] The first specific field may include information indicating the state of the control device 110 as first data.

[0079] The storage unit 124 is a storage device capable of storing data or information. Data can be stored in the storage unit 124 by the control unit 123. Data stored in the storage unit 124 can also be read out by the control unit 123. The storage unit 124 has a storage capacity equivalent to one data item contained in a specific field. When the storage unit 124 stores new data of the same item, the previously stored data is deleted and replaced with the new data.

[0080] The memory unit 124 may be a volatile memory device such as DRAM, or a non-volatile memory device such as an HDD or SSD. The memory unit 124 corresponds to the first memory unit.

[0081] The memory unit 124 can be considered a so-called cache memory. In that case, the act of the control unit 123 storing data in the memory unit 124 can also be described as caching data.

[0082] The communication device 22 comprises a wireless communication unit 221, a communication unit 222, a control unit 223, and a storage unit 224. The communication device 22 corresponds to the second communication device.

[0083] The wireless communication unit 221 is connected to the communication device 120 and is a wireless communication interface that performs wireless communication between the communication device 22 and the communication device 120. The frame that the wireless communication unit 221 receives from the communication device 120 corresponds to the second frame, and the frame that the wireless communication unit 221 transmits to the wireless communication unit 121 corresponds to the fifth frame. The wireless communication unit 221 corresponds to the third communication unit.

[0084] The communication standard of the wireless communication unit 221 is a wireless communication standard, and may be, for example, a wireless LAN (Local Area Network) communication standard such as IEEE 802.11a, b, g, n, ac, or ax, or a proximity wireless communication standard such as BLE.

[0085] The communication unit 222 is connected to the manufacturing apparatus 20 and is a communication interface that facilitates communication between the communication device 22 and the manufacturing apparatus 20. The frame that the communication unit 222 transmits to the manufacturing apparatus 20 corresponds to the third frame, and the frame that the communication unit 222 receives from the manufacturing apparatus 20 corresponds to the fourth frame. The communication unit 222 corresponds to the fourth communication unit.

[0086] The communication standard of the communication unit 222 may be a wired communication standard or a wireless communication standard. The communication standard of the communication unit 222 may be, for example, a parallel communication standard (for example, the SEMI standard E84 parallel communication standard).

[0087] The control unit 223 controls the communication unit 222 to transmit frames received by the wireless communication unit 221, and controls the wireless communication unit 221 to transmit frames received by the communication unit 222. The control unit 223 corresponds to a second control unit. The control unit 223 can be implemented by a processor (e.g., a CPU).

[0088] During the above control, the control unit 223 can store data contained in a predetermined specific field of the frame in the storage unit 224. The control unit 223 can also delete a specific field from a frame or add a specific field to a frame that does not have one.

[0089] Specifically, if the second frame received by the wireless communication unit 221 contains a first specific field, the control unit 223 stores the first data contained in the first specific field in the storage unit 224 and causes the communication unit 222 to transmit the second frame as a third frame. If the second frame received by the wireless communication unit 221 does not contain a first specific field, the control unit 223 generates a first specific field containing the first data stored in the storage unit 224 and adds it to the second frame, and causes the second frame with the added first specific field to transmit as a third frame.

[0090] Furthermore, if the second data contained in the second specific field of the fourth frame received by the communication unit 222 is not stored in the storage unit 224, the control unit 223 may store the second data in the storage unit 224 and have the wireless communication unit 221 transmit the fourth frame as the fifth frame. Alternatively, if the second data contained in the second specific field of the fourth frame received by the communication unit 222 is stored in the storage unit 224, the control unit 223 may delete the second specific field from the fourth frame and have the wireless communication unit 221 transmit the fourth frame from which the second specific field has been deleted as the fifth frame.

[0091] The second specific field may include information indicating the status of the manufacturing apparatus 20 as second data.

[0092] The storage unit 224 is a storage device capable of storing data or information. Data can be stored in the storage unit 224 by the control unit 223. Data stored in the storage unit 224 can also be read out by the control unit 223. The storage unit 224 has a storage capacity equivalent to one data item contained in a specific field. When the storage unit 224 stores new data of the same item, the previously stored data is deleted and replaced with the new data.

[0093] The memory unit 224 may be a volatile memory device such as DRAM, or a non-volatile memory device such as an HDD or SSD. The memory unit 224 corresponds to the second memory unit. The memory unit 224, like the memory unit 124, may correspond to a so-called cache memory.

[0094] The manufacturing apparatus 20 comprises a communication unit 201, a control unit 202, and a storage unit 203. The manufacturing apparatus 20 corresponds to the second device.

[0095] The communication unit 201 is connected to the communication device 22 and is a communication interface that enables communication between the manufacturing device 20 and the communication device 22. The communication standard of the communication unit 201 may be a wired communication standard or a wireless communication standard. The communication standard of the communication unit 201 may be, for example, a parallel communication standard (for example, the SEMI standard E84 parallel communication standard).

[0096] The control unit 202 controls the interlock communication between the transport trolley 10 and the manufacturing equipment 20. The control unit 202 may be implemented by a processor (e.g., a CPU).

[0097] The control unit 202 controls the communication unit 201 to perform interlock communication in synchronization with the transport trolley 10 (control device 110) via the communication devices 120 and 22. Specifically, the control unit 202 controls the communication unit 201 to perform interlock communication when the position of the transport trolley 10 on the track 7 is appropriate for interlock communication.

[0098] The storage unit 203 is a storage device capable of storing data or information. Data can be stored in the storage unit 203 by the control unit 202. Furthermore, data stored in the storage unit 203 can be read out by the control unit 202.

[0099] The memory unit 203 may be a volatile memory device such as DRAM, or a non-volatile memory device such as an HDD or SSD.

[0100] The processing of the communication system 2 configured as described above will now be explained.

[0101] Figure 3 is a flowchart showing a first example of the processing of the communication device 120 according to this embodiment. Figure 4 is an explanatory diagram showing a first example of the frame configuration according to this embodiment. Figure 5 is an explanatory diagram showing a second example of the frame configuration according to this embodiment.

[0102] The process shown in Figure 3 is an example of the process that the communication device 120 executes when it receives a frame that the control device 110 has sent to the manufacturing device 20.

[0103] In step S101, the communication unit 122 receives a frame from the control device 110. An example of the structure of the frame received by the communication unit 122 is shown in Figure 4.

[0104] As shown in Figure 4, the frame received by the communication unit 122 has a header 31 and a payload 32.

[0105] The header 31 includes at least address information indicating the source and destination of the frame. For example, the source included in the header 31 may be address information indicating the control device 110, or address information indicating the communication device 120. The destination included in the header 31 may be address information indicating the manufacturing device 20, or address information indicating the communication device 22.

[0106] The payload 32 has a field 33. The field 33 includes, for example, data 34 indicating the status of the control device 110 and data 35 indicating the status of the manufacturing device 20. The payload 32 may also contain various other types of data.

[0107] In step S102, the control unit 123 determines whether the same data as the data in field 33 of the frame received in step S101 is stored in the storage unit 124. Here, field 33 corresponds to a specific field. If it is determined that the same data as the data in field 33 of the frame received in step S101 is stored in the storage unit 124 (Yes in step S102), the process proceeds to step S111; otherwise (No in step S102), the process proceeds to step S103.

[0108] In step S103, the control unit 123 stores the data of field 33 of the frame received in step S101 in the storage unit 124.

[0109] In step S104, the control unit 123 transmits the frame received in step S101 as is via the wireless communication unit 121. The frame transmitted in step S104 (corresponding to the second frame) has the configuration shown in Figure 4.

[0110] In step S111, the control unit 123 deletes field 33 in the frame received in step S101. An example of the structure of a frame from which field 33 has been deleted is shown in Figure 5. The frame shown in Figure 5 does not have field 33. The header 31 shown in Figure 5 is the same as the header 31 shown in Figure 4.

[0111] In step S112, the control unit 123 transmits the frame from which the specific field was deleted in step S111 (corresponding to the second frame, see Figure 5) to the manufacturing apparatus 20 via the wireless communication unit 121.

[0112] Furthermore, when the communication device 22 receives a frame transmitted by the manufacturing device 20 to the control device 110, the processing performed by the communication device 22 is the same as the processing shown in Figure 3. In that case, the manufacturing device 20, control device 110, and communication device 120 in the explanation of Figure 3 should be read as control device 110, manufacturing device 20, and communication device 22, respectively. Also, the wireless communication unit 121, communication unit 122, control unit 123, and storage unit 124 in the explanation of Figure 3 should be read as wireless communication unit 221, communication unit 222, control unit 223, and storage unit 224, respectively.

[0113] Figure 6 is a flowchart showing a second example of the processing of the communication device according to this embodiment. The processing shown in Figure 6 is an example of the processing that the communication device 22 executes when it receives a frame transmitted by the manufacturing device 20 to the control device 110.

[0114] In step S201, the wireless communication unit 221 receives a frame from the communication device 120. The frame received by the wireless communication unit 221 may be a frame that includes field 33 (see Figure 4), or it may be a frame that does not include field 33 (see Figure 5).

[0115] In step S202, the control unit 223 determines whether the frame received in step S201 contains field 33. If it determines that the frame contains field 33 (Yes in step S202), the unit proceeds to step S203; otherwise (No in step S202), the unit proceeds to step S211.

[0116] In step S203, the control unit 223 stores the data in field 33 in the storage unit 224.

[0117] In step S204, the control unit 223 transmits the frame received in step S201 via the communication unit 222.

[0118] In step S211, the control unit 223 reads data from the storage unit 224. At this point, it is assumed that the storage unit 224 has data stored in it from step S203, which was performed earlier.

[0119] In step S212, the control unit 223 adds the field 33 containing the data read in step S211 to the frame received in step S201.

[0120] In step S213, the control unit 223 transmits the frame to which the field 33 was added in step S212 via the communication unit 222.

[0121] Furthermore, when the communication device 120 receives a frame transmitted by the manufacturing device 20 to the control device 110, the processing performed by the communication device 120 is the same as the processing shown in Figure 6. In that case, the manufacturing device 20, control device 110, and communication device 22 in the explanation of Figure 6 should be read as control device 110, manufacturing device 20, and communication device 120, respectively. Also, the wireless communication unit 221, communication unit 222, control unit 223, and storage unit 224 in the explanation of Figure 6 should be read as wireless communication unit 121, communication unit 122, control unit 123, and storage unit 124, respectively.

[0122] The following describes the processing of the communication system 2. Here, we will explain as an example the case in which the control device 110 and the manufacturing device 20 send and receive data including status data to and from each other.

[0123] Figure 7 is a sequence diagram showing a first example of the processing of the communication system 2 according to this embodiment.

[0124] In step S301, the control device 110 generates state data M1, which is data indicating the state of the control device 110.

[0125] In step S302, the control device 110 generates a frame containing the state data M1 generated in step S301 and transmits it to the communication device 120. The communication device 120 receives the transmitted frame.

[0126] The frame transmitted by the communication device 120 in step S302 has the frame configuration shown in Figure 4 and contains state data M1 as data 34. Data 35 does not contain any significant data. Data 35 may contain a value (e.g., 0) that indicates that no significant data is included. Data having state data M1 as data 34 and the value 0 as data 35 can also be expressed as data(M1,0). Furthermore, since the frame transmitted by the control device 110 in step S302 includes a header and data(M1,0), it can be expressed as "header + data(M1,0)". This expression method will be used hereafter as well.

[0127] In step S303, the communication device 120 stores the data (M1,0) contained in the frame received in step S302 into the storage unit 124. The process in step S303 corresponds to the process of storing the data in field 33 into the storage unit 124 (step S103 in Figure 3), based on the control unit 123's determination that the data in field 33 has not been stored in the storage unit 124 (No in step S102 in Figure 3).

[0128] In step S304, the communication device 120 transmits the frame received in step S302 to the communication device 22 (step S104 in Figure 3). The communication device 22 receives the transmitted frame.

[0129] In step S305, the communication device 22 stores the data (M1,0) contained in the frame received in step S304 into the storage unit 224. The process in step S305 corresponds to the process of storing the data in field 33 into the storage unit 224 (step S203 in Figure 6), based on the control unit 223's determination that the received frame contains field 33 (Yes in step S202 in Figure 6).

[0130] In step S306, the communication device 22 transmits the frame received in step S304 to the manufacturing device 20 (step S204 in Figure 6). The manufacturing device 20 receives the transmitted frame.

[0131] In step S311, the manufacturing apparatus 20 generates state data N1, which is data indicating the state of the manufacturing apparatus 20.

[0132] In step S312, the manufacturing apparatus 20 generates a frame containing the state data N1 generated in step S311 and transmits it to the communication device 22. The communication device 22 receives the transmitted frame.

[0133] The frame transmitted by the manufacturing apparatus 20 in step S312 has the frame configuration shown in Figure 4. The data contained in the frame transmitted by the manufacturing apparatus 20 in step S312 includes the status data M1 transmitted from the control device 110 as data 34, and the status data N1 as data 35. The frame transmitted by the manufacturing apparatus 20 in step S312 can be expressed as "header + data (M1, N1)".

[0134] In step S313, the communication device 22 stores the data (M1, N1) contained in the frame received in step S312 into the storage unit 224. The process in step S313 corresponds to the process of storing the data in field 33 into the storage unit 224 (step S103 in Figure 3), based on the control unit 223's determination that the data in field 33 has not been stored in the storage unit 224 (No in step S102 in Figure 3).

[0135] In step S314, the communication device 22 transmits the frame received in step S312 to the communication device 120 (step S104 in Figure 3). The communication device 120 receives the transmitted frame.

[0136] In step S315, the communication device 120 stores the data (M1, N1) contained in the frame received in step S314 in the storage unit 124. The process in step S315 corresponds to the process of storing the data in field 33 in the storage unit 124 (step S203 in Figure 6), based on the control unit 123's determination that the received frame contains field 33 (Yes in step S202 in Figure 6).

[0137] In step S316, the communication device 120 transmits the frame received in step S314 to the control device 110 (step S204 in Figure 6). The control device 110 receives the transmitted frame.

[0138] Figure 8 is a sequence diagram showing a second example of the processing of the communication system 2 according to this embodiment. The processing of the communication system 2 shown in Figure 8 is an example of processing that follows the processing shown in Figure 7. Therefore, the processing of the communication system 2 shown in Figure 8 is based on the premise that data (M1, N1) is already stored in the communication device 120 and the communication device 22.

[0139] In step S401, the control device 110 generates state data M1, which is data indicating the state of the control device 110. Here, it is assumed that the state of the control device 110 at the time step S401 is executed is the same as the state of the control device 110 at the time step S301 (see Figure 7) is executed.

[0140] In step S402, the control device 110 generates a frame containing the state data M1 generated in step S401 and transmits it to the communication device 120. The communication device 120 receives the transmitted frame.

[0141] The frame transmitted by the communication device 120 in step S402 has the frame configuration shown in Figure 4, and contains the status data M1 as data 34 and the status data N1 transmitted from the manufacturing device 20 as data 35. The frame transmitted by the control device 110 in step S402 can be expressed as "header + data (M1, N1)".

[0142] In step S403, the communication device 120 deletes the field 33 included in the frame received in step S402. The process in step S403 corresponds to the process of deleting the field 33 (step S111 in Figure 3) based on the control unit 123's determination that the data in the field 33 is stored in the storage unit 124 (Yes in step S102 in Figure 3).

[0143] In step S404, communication device 120 transmits a header-only frame, with field 33 removed in step S403, to communication device 22 (step S112 in Figure 3). Communication device 22 receives the transmitted frame.

[0144] In step S405, the communication device 22 adds a field 33 containing data (M1, N1) to the frame received in step S404. The process in step S405 corresponds to the process (steps S211-S212 in Figure 6) in which the control unit 223 determines that the received frame does not contain a field 33 (No in step S202 in Figure 6), reads the data (M1, N1) from the storage unit 224, and adds a field 33 containing the read data to the frame.

[0145] In step S406, the communication device 22 transmits the frame to the manufacturing device 20, with the field 33 added in step S405 (step S213 in Figure 6). The manufacturing device 20 receives the transmitted frame.

[0146] In step S411, the manufacturing apparatus 20 generates state data N1, which is data indicating the state of the manufacturing apparatus 20. Here, it is assumed that the state of the manufacturing apparatus 20 at the time step S411 is executed is the same as the state of the control device 110 at the time step S311 (see Figure 7) is executed.

[0147] In step S412, the manufacturing apparatus 20 generates a frame containing the state data N1 generated in step S411 and transmits it to the communication device 22. The communication device 22 receives the transmitted frame.

[0148] The frame transmitted by the manufacturing apparatus 20 in step S412 has the frame configuration shown in Figure 4. The data contained in the frame transmitted by the manufacturing apparatus 20 in step S412 includes state data M1 as data 34 and state data N1 as data 35. The frame transmitted by the manufacturing apparatus 20 in step S412 can be expressed as "header + data (M1, N1)".

[0149] In step S413, the communication device 22 deletes the field 33 included in the frame received in step S412. The process in step S413 corresponds to the process of deleting the field 33 (step S111 in Figure 3) based on the control unit 223's determination that the data in the field 33 is stored in the storage unit 224 (Yes in step S102 in Figure 3).

[0150] In step S414, communication device 22 sends a header-only frame, from which field 33 was deleted in step S413, to communication device 120 (step S112 in Figure 3). Communication device 120 receives the transmitted frame.

[0151] In step S415, the communication device 120 adds a field 33 containing data (M1, N1) to the frame received in step S414. The process in step S415 corresponds to the process (steps S211 to S212 in Figure 6) in which the control unit 123 determines that the received frame does not contain a field 33 (No in step S202 in Figure 6), reads the data (M1, N1) from the storage unit 124, and adds a field 33 containing the read data to the frame.

[0152] In step S416, the communication device 120 transmits the frame to the control device 110 with the field 33 added in step S415 (step S213 in Figure 6). The control device 110 receives the transmitted frame.

[0153] Figure 9 is a sequence diagram showing a third example of the processing of the communication system 2 according to this embodiment. The processing of the communication system 2 shown in Figure 9 is an example of processing that follows the processing shown in Figure 8. Therefore, the processing of the communication system 2 shown in Figure 9 is based on the premise that data (M1, N1) is already stored in the communication device 120 and the communication device 22.

[0154] In step S501, the control device 110 generates state data M2, which is data indicating the state of the control device 110. Here, it is assumed that the state of the control device 110 at the time step S501 is executed is different from the state of the control device 110 at the time step S301 (see Figure 7) or step S401 (see Figure 8) is executed.

[0155] In step S502, the control device 110 generates a frame containing the state data M2 generated in step S501 and transmits it to the communication device 120. The communication device 120 receives the transmitted frame.

[0156] The frame transmitted by the communication device 120 in step S502 has the frame configuration shown in Figure 4, and contains status data M2 as data 34 and status data N1 as data 35. The frame transmitted by the control device 110 in step S502 can be expressed as "header + data (M2, N1)".

[0157] In step S503, the communication device 120 stores the data (M2, N1) contained in the frame received in step S502 into the storage unit 124. The process in step S503 corresponds to the process of storing the data in field 33 into the storage unit 124 (step S103 in Figure 3), based on the control unit 123's determination that the data in field 33 has not been stored in the storage unit 124 (No in step S102 in Figure 3).

[0158] In step S504, the communication device 120 transmits the frame received in step S502 to the communication device 22 (step S104 in Figure 3). The communication device 22 receives the transmitted frame.

[0159] In step S505, the communication device 22 stores the data (M2, N1) contained in the frame received in step S504 into the storage unit 224. The process in step S505 corresponds to the process of storing the data in field 33 into the storage unit 224 (step S203 in Figure 6), based on the control unit 223's determination that the received frame contains field 33 (Yes in step S202 in Figure 6).

[0160] In step S506, the communication device 22 transmits the frame received in step S504 to the manufacturing device 20 (step S204 in Figure 6). The manufacturing device 20 receives the transmitted frame.

[0161] In step S511, the manufacturing apparatus 20 generates new state data N2, which is data indicating the state of the manufacturing apparatus 20.

[0162] In step S512, the manufacturing apparatus 20 generates a frame containing the state data N2 generated in step S511 and transmits it to the communication device 22. The communication device 22 receives the transmitted frame.

[0163] The frame transmitted by the manufacturing apparatus 20 in step S512 has the frame configuration shown in Figure 4. The data contained in the frame transmitted by the manufacturing apparatus 20 in step S512 includes state data M2 as data 34 and state data N2 as data 35. The frame transmitted by the manufacturing apparatus 20 in step S512 can be expressed as "header + data (M2, N2)".

[0164] In step S513, the communication device 22 stores the data (M2, N2) contained in the frame received in step S512 into the storage unit 224. The process in step S513 corresponds to the process of storing the data in field 33 into the storage unit 224 (step S103 in Figure 3), based on the control unit 223's determination that the data in field 33 has not been stored in the storage unit 224 (No in step S102 in Figure 3).

[0165] In step S514, the communication device 22 transmits the frame received in step S512 to the communication device 120 (step S104 in Figure 3). The communication device 120 receives the transmitted frame.

[0166] In step S515, the communication device 120 stores the data (M2, N2) contained in the frame received in step S514 into the storage unit 124. The process in step S515 corresponds to the process of storing the data in field 33 into the storage unit 124 (step S203 in Figure 6), based on the control unit 123's determination that the received frame contains field 33 (Yes in step S202 in Figure 6).

[0167] In step S516, the communication device 120 transmits the frame received in step S514 to the control device 110 (step S204 in Figure 6). The control device 110 receives the transmitted frame.

[0168] In the series of processes shown in Figures 7 to 9, frames that do not include field 33 may be transmitted and received in wireless communication between communication device 120 and communication device 22 (steps S404 and S414 in Figure 8). In this case, the time during which the radio waves are transmitted is shortened compared to when frames including field 33 are transmitted and received, thereby reducing interference with the radio waves of the wireless communication. In other words, it is possible to reduce the opportunities for radio wave interference to occur. Thus, the communication system 2 can reduce interference with radio waves of wireless communication.

[0169] Furthermore, in communication between devices, a device that successfully receives a frame may send an acknowledgment (ACK) to the device that sent the frame. In this case, the device that sent the frame may retransmit the frame if it does not receive an ACK within a certain period of time after sending the frame.

[0170] Furthermore, at the start of a series of interlock communications, a specific communication process for initiating the interlock communications (a so-called open sequence) may be executed. Also, at the end of a series of interlock communications, a specific communication process for terminating the interlock communications (a so-called close sequence) may be executed.

[0171] Furthermore, the frames transmitted by the communication device 22 to the manufacturing device 20 do not have to include the status data of the manufacturing device 20. Specifically, the frames transmitted by the communication device 22 to the manufacturing device 20 in step S306 in Figure 7, step S406 in Figure 8, and step S506 in Figure 9 do not have to include the status data of the manufacturing device 20 (in those steps, "0", "N1", and "N1", respectively). Also, the frames transmitted by the manufacturing device 20 to the communication device 22 do not have to include the status data of the control device 110. Specifically, the frames transmitted by the manufacturing device 20 to the communication device 22 in step S312 in Figure 7, step S412 in Figure 8, and step S512 in Figure 9 do not have to include the status data of the control device 110 (in that step, "M1", "M1", and "M2", respectively). In that case, the communication device 22, upon receiving a frame that does not contain the status data of the control device 110, can add the status data of the control device 110 that was included in the frame received immediately before to the frame and proceed with the subsequent processing (steps S313, S413, and S513, respectively).

[0172] (2) Communication between the control server 30 and the transport trolley 10 Figure 10 is a block diagram showing a second example of the functional configuration of the communication system according to this embodiment. The communication system shown in Figure 10 is also referred to as communication system 3.

[0173] As shown in Figure 10, the communication system 3 comprises a control server 30, a communication device 37, and a transport cart 10. The communication device 37 may also be provided as a function of the control server 30.

[0174] The control server 30 comprises a communication unit 301, a control unit 302, and a storage unit 303. The control server 30 corresponds to the first device.

[0175] The communication unit 301 is connected to the communication device 37 and is a communication interface that facilitates communication between the control server 30 and the communication device 37. The communication standard of the communication unit 301 may be a wired communication standard or a wireless communication standard. For example, the communication standard of the communication unit 301 may be a wired LAN communication standard (e.g., IEEE 802.3).

[0176] The control unit 302 controls the operation of the transport trolley 10. The control unit 302 may be implemented by a processor (e.g., a CPU).

[0177] The control unit 302 transmits a frame (corresponding to the first frame) that includes a specific field (corresponding to the first specific field) containing command data. The command data contains information indicating an instruction from the control server 30 to the transport trolley 10. The first frame also includes a command sequence number (corresponding to the first sequence number). The command sequence number is one of a series of sequence numbers assigned by the control server 30 to a series of command data transmitted by the control server 30.

[0178] The storage unit 303 is a storage device capable of storing data or information. Data can be stored in the storage unit 303 by the control unit 302. Furthermore, data stored in the storage unit 303 can be read out by the control unit 302.

[0179] The memory unit 303 may be a volatile memory device such as DRAM, or a non-volatile memory device such as an HDD or SSD.

[0180] The communication device 37 comprises a wireless communication unit 371, a communication unit 372, a control unit 373, and a storage unit 374. The communication device 37 corresponds to the first communication device.

[0181] The wireless communication unit 371 is connected to the communication device 120 and is a wireless communication interface that performs wireless communication between the communication device 37 and the communication device 120. The frame that the wireless communication unit 371 transmits to the communication device 120 corresponds to the second frame, and the frame that the wireless communication unit 371 receives from the communication device 120 corresponds to the fifth frame. The wireless communication unit 371 corresponds to the second communication unit.

[0182] The communication standard of the wireless communication unit 371 is a wireless communication standard, and may be a wireless LAN communication standard such as IEEE 802.11a, b, g, n, ac, or ax.

[0183] The communication unit 372 is connected to the control server 30 and is a communication interface that facilitates communication between the communication device 37 and the control server 30. The frame that the communication unit 372 receives from the control server 30 corresponds to the first frame, and the frame that the communication unit 372 transmits to the control server 30 corresponds to the sixth frame. The communication unit 372 corresponds to the first communication unit.

[0184] The communication standard of the communication unit 372 may be a wired communication standard or a wireless communication standard. For example, the communication standard of the communication unit 372 may be a wired LAN communication standard (e.g., IEEE 802.3).

[0185] The control unit 373 controls the wireless communication unit 371 to transmit frames received by the communication unit 372, and controls the communication unit 372 to transmit frames received by the wireless communication unit 371. The control unit 373 corresponds to the first control unit. The control unit 373 can be implemented by a processor (e.g., a CPU).

[0186] During the above control, the control unit 373 can store data contained in a predetermined field (also called a specific field) of the frame in the storage unit 374. The control unit 373 can also delete a specific field from a frame or add a specific field to a frame that does not have one.

[0187] Specifically, if the data (corresponding to the first data) contained in a specific field (corresponding to the first specific field) of the first frame received by the communication unit 372 is not stored in the storage unit 374, the control unit 373 stores the first data in the storage unit 374 and causes the first frame to be transmitted as the second frame by the wireless communication unit 371. Furthermore, if the first data contained in the first specific field of the first frame received by the communication unit 372 is stored in the storage unit 374, the control unit 373 deletes the first specific field from the first frame and causes the first frame from which the first specific field has been deleted to be transmitted as the second frame by the wireless communication unit 371.

[0188] Furthermore, if the fifth frame received by the wireless communication unit 371 includes a second specific field, the control unit 373 may store the second data included in the second specific field in the storage unit 374 and have the communication unit 372 transmit the fifth frame as a sixth frame. Alternatively, if the fifth frame received by the wireless communication unit 371 does not include a second specific field, the control unit 373 may generate a second specific field including the second data stored in the storage unit 374 and add it to the fifth frame, and have the communication unit 372 transmit the fifth frame with the added second specific field as a sixth frame.

[0189] Furthermore, when the control unit 373 stores the first data contained in the first specific field of the first frame in the storage unit 374, it stores the command sequence number contained in the first frame in association with the command data in the storage unit 374. Then, when the first specific field is deleted from the first frame, the control unit 373 changes the command sequence number contained in the first frame to the command sequence number stored in the storage unit 374 in association with the command data.

[0190] Furthermore, when the control unit 373 stores the second data contained in the second specific field in the storage unit 374, it stores the second sequence number contained in the fifth frame in association with the response data in the storage unit 374. Then, when the control unit 373 generates the second specific field and adds it to the second frame, it generates the second specific field containing the response data stored in the storage unit 124 in association with the second sequence number contained in the second frame and adds it to the second frame.

[0191] The storage unit 374 is a storage device capable of storing data or information. Data can be stored in the storage unit 374 by the control unit 373. Data stored in the storage unit 374 can also be read out by the control unit 373. The storage unit 374 has a command storage unit, which is a storage area for storing command data (also called a command storage area), and a response storage unit, which is a storage area for storing response data (also called a response storage area). Each of the above storage areas has a storage capacity equivalent to one data item contained in a specific field. When new data of the same item is stored in each storage area, the previously stored data is deleted and replaced with the new data.

[0192] The memory unit 374 may be a volatile memory device such as DRAM, or a non-volatile memory device such as an HDD or SSD. The memory unit 374 corresponds to the first memory unit. The memory unit 374 may correspond to a so-called cache memory.

[0193] The transport trolley 10 includes a control device 110 and a communication device 120.

[0194] The communication device 120 comprises a wireless communication unit 121, a communication unit 122, a control unit 123, and a storage unit 124. The communication device 120 corresponds to the second communication device.

[0195] The wireless communication unit 121 is connected to the communication device 37 and is a wireless communication interface that performs wireless communication between the communication device 120 and the communication device 37. The frame that the wireless communication unit 121 receives from the communication device 37 corresponds to the second frame, and the frame that the wireless communication unit 121 transmits to the communication device 37 corresponds to the fifth frame. The wireless communication unit 121 corresponds to the third communication unit.

[0196] The communication standard of the wireless communication unit 121 is a wireless communication standard, and may be a wireless LAN communication standard such as IEEE 802.11a, b, g, n, ac, or ax.

[0197] The communication unit 122 is connected to the control device 110 and is a communication interface that facilitates communication between the communication device 120 and the control device 110. The frame that the communication unit 122 transmits to the control device 110 corresponds to the third frame, and the frame that the communication unit 122 receives from the control device 110 corresponds to the fourth frame. The communication unit 122 corresponds to the fourth communication unit.

[0198] The communication standard of the communication unit 122 may be a wired communication standard or a wireless communication standard. The communication standard of the communication unit 122 may be, for example, a serial communication standard (e.g., RS-232C) or a wired LAN communication standard (e.g., IEEE802.3).

[0199] The control unit 123 controls the wireless communication unit 121 to transmit frames received by the communication unit 122, and also controls the communication unit 122 to transmit frames received by the wireless communication unit 121. The control unit 123 corresponds to the second control unit.

[0200] During the above control, the control unit 123 can store data contained in a predetermined field (also called a specific field) of the frame in the storage unit 124. The control unit 123 can also delete a specific field from a frame or add a specific field to a frame that does not have one.

[0201] Specifically, if the second frame received by the wireless communication unit 121 contains a first specific field, the control unit 123 stores the first data contained in the first specific field in the storage unit 124 and causes the communication unit 222 to transmit the second frame as a third frame. If the second frame received by the wireless communication unit 121 does not contain a first specific field, the control unit 123 generates a first specific field containing the first data stored in the storage unit 124 and adds it to the second frame, and causes the second frame with the added first specific field to transmit as a third frame.

[0202] Furthermore, if the data (corresponding to the second data) contained in a specific field (corresponding to the second specific field) of the fourth frame received by the communication unit 122 is not stored in the storage unit 124, the control unit 123 stores the second data in the storage unit 124 and causes the fourth frame to be transmitted as the fifth frame by the wireless communication unit 121. Also, if the second data contained in the second specific field of the fourth frame received by the communication unit 122 is stored in the storage unit 124, the control unit 123 deletes the second specific field from the fourth frame and causes the fourth frame from which the second specific field has been deleted to be transmitted as the fifth frame by the wireless communication unit 121.

[0203] Furthermore, when the control unit 123 stores the first data contained in the first specific field in the storage unit 124, it stores the first sequence number contained in the second frame in association with the command data in the storage unit 124. Then, when the control unit 123 generates the first specific field and adds it to the second frame, it generates the first specific field containing the command data stored in the storage unit 124 in association with the first sequence number contained in the second frame and adds it to the second frame.

[0204] Furthermore, when the control unit 123 stores the second data contained in the second specific field of the fourth frame in the storage unit 124, it stores the second sequence number contained in the fourth frame in the storage unit 124 in association with the response data. Then, if the second specific field is deleted from the fourth frame, the control unit 123 changes the second sequence number contained in the fourth frame to the second sequence number stored in the storage unit 124 in association with the second sequence number.

[0205] The storage unit 124 is a storage device capable of storing data or information. Data can be stored in the storage unit 124 by the control unit 123. Data stored in the storage unit 124 can also be read out by the control unit 123. In this embodiment, the storage unit 124 has a command storage unit, which is a storage area for storing command data (also called a command storage area), and a response storage unit, which is a storage area for storing response data (also called a response storage area). Each of the above storage areas has a storage capacity equivalent to one data item contained in a specific field. When new data of the same item is stored in each storage area, the previously stored data is deleted and replaced with the new data.

[0206] The memory unit 124 may be a volatile memory device such as DRAM, or a non-volatile memory device such as an HDD or SSD. The memory unit 124 corresponds to a second memory unit. The memory unit 124 may correspond to a so-called cache memory.

[0207] The control device 110 comprises a communication unit 111, a control unit 112, and a storage unit 113. The control device 110 corresponds to the second device.

[0208] The communication unit 111 is connected to the communication device 120 and is a communication interface that enables communication between the communication device 120 and the control device 110. The communication standard of the communication unit 111 may be a wired communication standard or a wireless communication standard. The communication standard of the communication unit 111 may be, for example, a serial communication standard (e.g., RS-232C) or a wired LAN communication standard (e.g., IEEE802.3).

[0209] The control unit 112 controls the transport cart 10 according to commands it receives from the control server 30. The control unit 112 receives frames sent by the control server 30 addressed to the transport cart 10 and controls the transport cart 10 according to the commands contained in the command data included in the received frame. The control unit 112 also transmits a frame (corresponding to the fourth frame) that includes a specific field (corresponding to the second specific field) containing response data. The response data contains information indicating the response from the transport cart 10 to the control server 30. The fourth frame also includes a response sequence number (corresponding to the second sequence number). The response sequence number is one of a series of sequence numbers assigned by the transport cart 10 to a series of response data transmitted by the transport cart 10.

[0210] The storage unit 113 is a storage device capable of storing data or information. Data can be stored in the storage unit 113 by the control unit 112. Furthermore, data stored in the storage unit 113 can be read out by the control unit 112.

[0211] The memory unit 113 may be a volatile memory device such as DRAM, or a non-volatile memory device such as an HDD or SSD.

[0212] The processing of the communication system 3 configured as described above will now be explained.

[0213] Figure 11 is a flowchart showing a third example of the processing of the communication device according to this embodiment. Figure 12 is an explanatory diagram showing a third example of the frame configuration according to this embodiment. Figure 13 is an explanatory diagram showing a fourth example of the frame configuration according to this embodiment.

[0214] The process shown in Figure 11 is an example of the process that the communication device 37 executes when it receives a frame that the control server 30 has sent to the control device 110.

[0215] In step S601, the communication unit 372 receives a frame from the control server 30. An example of the structure of the frame received by the communication unit 372 is shown in Figure 12.

[0216] As shown in Figure 12, the frame received by the communication unit 372 has a header 41 and a payload 42.

[0217] The header 41 includes at least address information indicating the source and destination of the frame. For example, the source included in the header 41 is address information indicating the control server 30, and the destination is address information indicating the control device 110.

[0218] Payload 42 includes sequence number 44 and field 43. Field 43 contains content data. Field 43 includes command data if the frame is transmitted from control server 30 to control device 110, and includes response data if the frame is transmitted from control device 110 to control server 30. The command data or response data that field 43 may contain is also called content data. Payload 42 may also contain various other types of data.

[0219] In step S602, the control unit 373 determines whether the same data as the data in field 43 of the frame received in step S601 is stored in the command storage unit of the storage unit 374. Here, field 43 corresponds to a specific field. If it is determined that the same data as the data in field 43 of the frame received in step S601 is stored in the command storage unit of the storage unit 374 (Yes in step S602), the process proceeds to step S611; otherwise (No in step S602), the process proceeds to step S603.

[0220] In step S603, the control unit 373 stores the data of field 43 of the frame received in step S601 in the command storage unit 374. At this time, the control unit 373 stores the sequence number included in the frame received in step S601 in the command storage unit 374, associating it with the command data. In other words, the control unit 373 stores the sequence number of the frame received in step S601 in the command storage unit 374, associating it with the command data.

[0221] In step S604, the control unit 373 transmits the frame received in step S601 via the wireless communication unit 371. The frame transmitted in step S604 (corresponding to the second frame) has the configuration shown in Figure 12.

[0222] In step S611, the control unit 373 deletes field 43 from the frame received in step S601. An example of the structure of a frame from which field 43 has been deleted is shown in Figure 13. The header 41 shown in Figure 13 is the same as the header 41 shown in Figure 12. The payload 42 shown in Figure 13 does not contain field 43.

[0223] In step S612, the control unit 373 changes the sequence number of the frame from which a specific field was deleted in step S611. Specifically, the control unit 373 changes the sequence number included in the frame to the sequence number stored in the command storage unit of the storage unit 374 in association with the command data. Here, the sequence number is the command sequence number. The sequence number is also stored in the command storage unit of the storage unit 124 of the communication device 120 that receives the frame, in association with the command data. As will be described later, when the communication device 120 receives a frame containing only the header and sequence number, it reads the corresponding command data from the command storage unit based on the sequence number, adds it, and transmits it to the control device 110.

[0224] In step S613, the control unit 373 transmits the frame whose sequence number was changed in step S612 (corresponding to the second frame, see Figure 13) via the wireless communication unit 371.

[0225] Furthermore, when the communication device 120 receives a frame containing response data that the control device 110 has sent to the control server 30, the processing performed by the communication device 120 is the same as the processing shown in Figure 11. In this case, the command storage units of the wireless communication unit 371, communication unit 372, control unit 373, and storage unit 374 in the explanation of Figure 11 should be read as the response storage units of the wireless communication unit 121, communication unit 122, control unit 123, and storage unit 124, respectively. Also, the sequence number refers to the response sequence number.

[0226] Figure 14 is a flowchart showing a fourth example of the processing of the communication device according to this embodiment. The processing shown in Figure 14 is an example of the processing that the communication device 120 executes when the communication device 120 receives a frame that the control server 30 has sent to the control device 110.

[0227] In step S701, the wireless communication unit 121 receives a frame from the communication device 37. The frame received by the wireless communication unit 121 may be a frame that includes field 43 (see Figure 12), or it may be a frame that does not include field 43 (see Figure 13).

[0228] In step S702, the control unit 123 determines whether the frame received in step S701 contains field 43. If it determines that the frame contains field 43 (Yes in step S702), the process proceeds to step S703; otherwise (No in step S702), the process proceeds to step S711.

[0229] In step S703, the control unit 123 stores the data in field 43 in the command storage unit 124. At this time, the control unit 123 stores the sequence number included in the frame received in step S701 in the command storage unit 124, associating it with the command data.

[0230] In step S704, the control unit 123 transmits the frame received in step S701 via the communication unit 122.

[0231] In step S711, the control unit 123 reads data from the command storage unit of the storage unit 124. At this point, it is assumed that the command storage unit of the storage unit 124 contains data that was stored in step S703, which was executed earlier.

[0232] In step S712, the control unit 123 adds the field 43 containing the data read in step S711 to the frame received in step S701.

[0233] In step S713, the control unit 123 transmits the frame to which the field 43 was added in step S712 via the communication unit 122.

[0234] Furthermore, when the communication device 37 receives a frame containing response data that the control device 110 has sent to the control server 30, the processing performed by the communication device 37 is the same as the processing shown in Figure 14. In this case, the command storage units of the wireless communication unit 121, communication unit 122, control unit 123, and storage unit 124 in the explanation of Figure 14 should be read as the response storage units of the wireless communication unit 371, communication unit 372, control unit 373, and storage unit 374, respectively. Also, the sequence number refers to the response sequence number.

[0235] The following describes the processing of the communication system 3. Here, we will explain as an example the case in which the control server 30 sends command data to the control device 110, and the control device 110 sends response data to the control server 30.

[0236] Figure 15 is a sequence diagram showing a first example of the processing of the communication system 3 according to this embodiment.

[0237] In step S801, the control server 30 generates command data C1 to which command sequence number S1 is appended. Command data C1 contains information indicating an instruction to the control device 110.

[0238] In step S802, the control server 30 generates a frame containing the command data C1 generated in step S801 and sends it to the communication device 37. The communication device 37 receives the transmitted frame.

[0239] The frame transmitted by the control server 30 in step S802 has the frame structure shown in Figure 12, with sequence number S1 as sequence number 44, and command data C1 as content data in field 43. The data, including sequence number S1 as sequence number 44 and command data C1 as content data in field 43, can also be expressed as data(S1,C1). Since the frame transmitted by the control server 30 in step S802 includes a header and data(S1,C1), it can be expressed as "header + data(S1,C1)". This expression method will be used hereafter as well.

[0240] In step S803, the communication device 37 stores the data (S1, C1) contained in the frame received in step S802 into the command storage unit of the storage unit 374. The process in step S803 corresponds to the process of storing the data in field 43 (i.e., command data C1) into the storage unit 374 (step S603 in Figure 11), based on the control unit 373's determination that the data in field 43 (i.e., command data C1) has not been stored in the command storage unit of the storage unit 374 (No in step S102 in Figure 3).

[0241] In step S804, communication device 37 transmits the frame received in step S802 to communication device 120 (step S604 in Figure 11). Communication device 120 receives the transmitted frame.

[0242] In step S805, the communication device 120 stores the data (S1, C1) contained in the frame received in step S804 in the command storage unit of the storage unit 124. The process in step S305 corresponds to the process of storing the data in field 43 in the command storage unit of the storage unit 124 (step S703 in Figure 14), based on the control unit 123's determination that the received frame contains field 43 (Yes in step S702 in Figure 14).

[0243] In step S806, the communication device 120 transmits the frame received in step S804 to the control device 110 (step S704 in Figure 14). The control device 110 receives the transmitted frame.

[0244] In step S811, the control device 110 generates response data R1 to which the response sequence number T1 is appended. The response data R1 contains information indicating the response to the command contained in the command data C1 contained in the frame transmitted in step S801.

[0245] In step S812, the control device 110 generates a frame containing the response data R1 generated in step S811 and transmits it to the communication device 120. The communication device 120 receives the transmitted frame.

[0246] The frame transmitted by the control device 110 in step S812 has the frame structure shown in Figure 12, has sequence number T1 as sequence number 44, and has response data R1 as content data in field 43. The data, which includes sequence number T1 as sequence number 44 and response data R1 as content data in field 43, can also be expressed as data(T1,R1). Since the frame transmitted by the control device 110 in step S812 includes a header and data(T1,R1), it can be expressed as "header + data(T1,R1)". This expression method will be used thereafter.

[0247] In step S813, the communication device 120 stores the data (T1, R1) contained in the frame received in step S812 into the response storage unit of the storage unit 124. The process in step S813 corresponds to the process of storing the data in field 43 into the response storage unit of the storage unit 124 (step S603 in Figure 11), based on the control unit 123's determination that the data in field 43 (i.e., response data R1) has not been stored in the response storage unit of the storage unit 124 (No in step S602 in Figure 11).

[0248] In step S814, the communication device 120 transmits the frame received in step S812 to the communication device 37 (step S604 in Figure 11). The communication device 37 receives the transmitted frame.

[0249] In step S815, the communication device 37 stores the data (T1, R1) contained in the frame received in step S814 in the response storage unit of the storage unit 374. The process in step S815 corresponds to the process of storing the data in field 43 in the response storage unit of the storage unit 374 (step S603 in Figure 11), based on the control unit 373's determination that the received frame contains field 43 (Yes in step S602 in Figure 11).

[0250] In step S816, the communication device 37 transmits the frame received in step S814 to the control server 30 (step S604 in Figure 11). The control server 30 receives the transmitted frame.

[0251] Figure 16 is a sequence diagram showing a second example of the processing of the communication system 3 according to this embodiment. The processing of the communication system 3 shown in Figure 16 is an example of processing that follows the processing shown in Figure 15. Therefore, the processing of the communication system 3 shown in Figure 16 is based on the premise that data (S1, C1) is already stored in the communication device 37 and the communication device 120.

[0252] In step S901, the control server 30 generates command data C1 to which command sequence number S2 is appended. Command data C1 contains information indicating an instruction to the control device 110. The command data C1 generated by the control server 30 in step S901 is the same as the command data C1 generated by the control server 30 in step S801 (see Figure 15).

[0253] In step S902, the control server 30 generates a frame containing the command data C1 generated in step S901 and sends it to the communication device 37. The communication device 37 receives the transmitted frame.

[0254] The frame transmitted by the control server 30 in step S902 has the frame structure shown in Figure 12, has sequence number S2 as sequence number 44, and has command data C1 as content data in field 43. The frame transmitted by the control server 30 in step S902 can be expressed as "header + data (S2, C1)".

[0255] In step S903, the communication device 37 deletes field 43 included in the frame received in step S902, and changes the command sequence number S2 included in the frame to command sequence number S1. The processing in step S903 corresponds to the process of deleting field 43 and then changing the sequence number (steps S611 to S612 in Figure 11), based on the control unit 373's determination that the data in field 43 is stored in the command storage unit of the storage unit 374 (Yes in step S602 in Figure 11).

[0256] In step S904, the communication device 37 transmits the frame processed in step S903 to the communication device 120 (step S613 in Figure 11). The communication device 120 receives the transmitted frame ("header + data (S1)").

[0257] In step S905, the communication device 120 adds a field 43 containing the command data C1 to the frame received in step S904. The process in step S905 corresponds to the process (steps S711-S712 in Figure 14) in which the control unit 123 determines that the received frame does not contain the field 43 (No in step S702 in Figure 14), reads the command data C1 associated with the command sequence number S1 from the command storage unit of the storage unit 124, and adds the field 43 containing the read command data C1 to the frame.

[0258] In step S906, the communication device 120 transmits a frame with the field 43 added in step S905 ("header + data (S1, C1)") to the control device 110 (step S713 in Figure 14). The control device 110 receives the transmitted frame.

[0259] In step S911, the control device 110 generates response data R2 to which the response sequence number T2 is appended. The response data R2 contains information indicating the response to the command contained in the command data C1 contained in the frame transmitted in step S901.

[0260] In step S912, the control device 110 generates a frame containing the response data R2 generated in step S911 and transmits it to the communication device 120. The communication device 120 receives the transmitted frame.

[0261] The frame transmitted by the control device 110 in step S912 has the frame configuration shown in Figure 12, has sequence number T2 as sequence number 44, and has response data R2 as content data in field 43. The frame transmitted by the control device 110 in step S912 can be expressed as "header + data (T2, R2)".

[0262] In step S913, the communication device 120 stores the data (T2, R2) contained in the frame received in step S912 into the response storage unit of the storage unit 124. The process in step S913 corresponds to the process of storing the data in field 43 into the response storage unit of the storage unit 124 (step S603 in Figure 11) based on the control unit 123's determination that the data in field 43 (i.e., response data R2) has not been stored in the response storage unit of the storage unit 124 (No in step S602 in Figure 11). Note that when the control unit 123 stores the data (T2, R2) into the response storage unit of the storage unit 124, the data (T1, R1) that was stored in the response storage unit of the storage unit 124 before the storage is erased.

[0263] In step S914, the communication device 120 transmits the frame received in step S912 to the communication device 37 (step S604 in Figure 11). The communication device 37 receives the transmitted frame.

[0264] In step S915, the communication device 37 stores the data (T2, R2) contained in the frame received in step S914 into the response storage unit of the storage unit 374. The process in step S915 corresponds to the process of storing the data in field 43 into the response storage unit of the storage unit 374 (step S603 in Figure 11), based on the control unit 373's determination that the received frame contains field 43 (Yes in step S602 in Figure 11). Note that when the control unit 373 stores the data (T2, R2) into the response storage unit of the storage unit 374, the data (T1, R1) that was stored in the response storage unit of the storage unit 374 before the storage is erased.

[0265] In step S916, the communication device 37 transmits the frame received in step S914 to the control server 30 (step S604 in Figure 11). The control server 30 receives the transmitted frame.

[0266] Figure 17 is a sequence diagram showing a third example of the processing of the communication system 3 according to this embodiment. The processing of the communication system 3 shown in Figure 17 is an example of processing that follows the processing shown in Figure 16. Therefore, the processing of the communication system 3 shown in Figure 17 is based on the premise that data (S1, C1) is already stored in the communication device 37 and the communication device 120.

[0267] In step S1001, the control server 30 generates command data C1 to which command sequence number S3 is appended. Command data C1 contains information indicating an instruction to the control device 110. The command data C1 generated by the control server 30 in step S1001 is the same as the command data C1 generated by the control server 30 in step S801 (see Figure 15).

[0268] In step S1002, the control server 30 generates a frame containing the command data C1 generated in step S1001 and sends it to the communication device 37. The communication device 37 receives the transmitted frame.

[0269] The frame transmitted by the control server 30 in step S1002 has the frame structure shown in Figure 12, has sequence number S3 as sequence number 44, and has command data C1 as content data in field 43. The frame transmitted by the control server 30 in step S1002 can be expressed as "header + data (S3, C1)".

[0270] In step S1003, the communication device 37 deletes field 43 included in the frame received in step S1002, and changes the command sequence number S3 included in the frame to command sequence number S1. The process in step S1003 corresponds to the process of deleting field 43 and then changing the sequence number (steps S611 to S612 in Figure 11) based on the control unit 373's determination that the data in field 43 is stored in the command storage unit of the storage unit 374 (Yes in step S602 in Figure 11).

[0271] In step S1004, the communication device 37 transmits the frame processed in step S1003 to the communication device 120 (step S613 in Figure 11). The communication device 120 receives the transmitted frame.

[0272] In step S1005, the communication device 120 adds a field 43 containing command data C1 to the frame received in step S1004. The process in step S1005 corresponds to the process (steps S711-S712 in Figure 14) in which the control unit 123 determines that the received frame does not contain field 43 (No in step S702 in Figure 14), reads command data C1 associated with command sequence number S1 from the command storage unit of the storage unit 124, and adds a field 43 containing the read command data C1 to the frame.

[0273] In step S1006, the communication device 120 transmits the frame with the field 43 added in step S1005 to the control device 110 (step S713 in Figure 14). The control device 110 receives the transmitted frame.

[0274] In step S1011, the control device 110 generates response data R2 to which the response sequence number T3 is added. The response data R2 contains information indicating the response to the command contained in the command data C1 contained in the frame transmitted in step S1001. Furthermore, the response data R2 generated by the control device 110 in step S1011 is the same as the response data R2 generated by the control server 30 in step S911 (see Figure 16).

[0275] In step S1012, the control device 110 generates a frame containing the response data R2 generated in step S1011 and transmits it to the communication device 120. The communication device 120 receives the transmitted frame.

[0276] The frame transmitted by the control device 110 in step S1012 has the frame configuration shown in Figure 12, has sequence number T3 as sequence number 44, and has response data R2 as content data in field 43. The frame transmitted by the control device 110 in step S1012 can be expressed as "header + data (T3, R2)".

[0277] In step S1013, the communication unit 122 deletes field 43 included in the frame received in step S1012, and changes the response sequence number T3 included in the frame to response sequence number T2. The processing in step S1013 corresponds to the process of deleting field 43 and then changing the sequence number (steps S611 to S612 in Figure 11) based on the control unit 123's determination that the data in field 43 is stored in the response storage unit of the storage unit 124 (Yes in step S602 in Figure 11).

[0278] In step S1014, the communication unit 122 transmits the frame processed in step S1013 to the communication device 37 (step S613 in Figure 11). The communication device 37 receives the transmitted frame.

[0279] In step S1015, the communication device 37 adds a field 43 containing the response data R2 to the frame received in step S1014. The process in step S1015 corresponds to the process (steps S711-S712 in Figure 14) in which the control unit 373 determines that the received frame does not contain the field 43 (No in step S702 in Figure 14), reads the response data R2 associated with the response sequence number T2 from the response storage unit of the storage unit 374, and adds the field 43 containing the read response data R2 to the frame.

[0280] In step S1016, the communication device 37 transmits the frame with the field 43 added in step S1015 to the control server 30 (step S713 in FIG. 14). The control server 30 receives the transmitted frame.

[0281] In a series of processes shown in FIGS. 15 to 17, frames not including the field 43 may be transmitted and received in the wireless communication between the communication device 37 and the communication device 120 (step S904 in FIG. 16, and steps S1004 and S1014 in FIG. 17). At this time, the interference of the radio waves of the wireless communication can be reduced by shortening the time during which the radio waves of the wireless communication are transmitted, as compared with the case where frames including the field 43 are transmitted and received. Thus, the communication system 3 can reduce the interference of the radio waves of the wireless communication.

[0282] Note that the present invention can be realized not only as an apparatus, but also as a method in which processing means constituting the apparatus are steps, or as a program causing a computer to execute those steps, or as a recording medium such as a computer-readable CD-ROM recording the program, or as information, data, or signals indicating the program. And those programs, information, data, and signals may be distributed via a communication network such as the Internet.

[0283] As described above, the base station and the like of the present invention have been described based on the embodiments. However, the present invention is not limited to these embodiments. As long as the gist of the present invention is not deviated from, forms obtained by applying various modifications conceived by those skilled in the art to these embodiments, or forms constructed by combining constituent elements in different embodiments are also included in the scope of the present invention.

Industrial Applicability

[0284] The present invention can be applied to a communication system and a communication device that perform wireless communication.

Explanation of Signs

[0285] 1, 2, 3 Communication Systems 5 Goods 7 orbit 10 Transport carts 20 Manufacturing equipment 22, 37, 120 Communication equipment 30 Control Server 31, 41 headers 32, 42 payloads Fields 33 and 43 34, 35 Data 44 Sequence Number 110 Control device 111, 122, 201, 222, 301, 372 Communications Department 112, 123, 202, 223, 302, 373 Control Unit 113, 124, 203, 224, 303, 374 Storage section 121, 221, 371 Wireless Communication Section

Claims

1. A communication system comprising a first communication device connected to a first device and a second communication device connected to a second device, The first communication device is A first communication unit that receives a first frame from the first device, First memory unit and, A second communication unit that transmits a second frame to the second device via wireless communication, The first control unit, (a) If the first data included in the first specific field of the first frame received by the first communication unit is not stored in the first storage unit, the first data is stored in the first storage unit, and the first frame is transmitted by the second communication unit as the second frame. (b) If the first data contained in the first specific field of the first frame received by the first communication unit is stored in the first storage unit, the first specific field is deleted from the first frame, and the first frame from which the first specific field has been deleted is transmitted by the second communication unit as the second frame. It comprises a first control unit, The second communication device is A third communication unit that receives the second frame from the first communication device via wireless communication, The second memory unit, A fourth communication unit that transmits a third frame to the second device, The second control unit, (c) If the second frame received by the third communication unit includes the first specific field, the first data included in the first specific field is stored in the second storage unit, and the second frame is transmitted by the fourth communication unit as the third frame. (d) If the second frame received by the third communication unit does not include the first specific field, the fourth communication unit generates the first specific field including the first data stored in the second storage unit and adds it to the second frame, and causes the second frame with the first specific field added to be transmitted as the third frame. It comprises a second control unit. Communication system.

2. The aforementioned fourth communication unit further, The second device receives the fourth frame transmitted after receiving the third frame, The aforementioned third communications unit further, The fifth frame is transmitted to the first communication device via wireless communication. The aforementioned second control unit further, (e) If the second data included in the second specific field of the fourth frame received by the fourth communication unit is not stored in the second storage unit, the second data is stored in the second storage unit, and the fourth frame is transmitted by the third communication unit as the fifth frame. (f) If the second data contained in the second specific field of the fourth frame received by the fourth communication unit is stored in the second storage unit, the second specific field is deleted from the fourth frame, and the fourth frame from which the second specific field has been deleted is transmitted by the third communication unit as the fifth frame. The aforementioned second communication unit further, The fifth frame is received from the second communication device via wireless communication. The aforementioned first communications unit further, The sixth frame is transmitted to the first communication device. The first control unit further, (g) If the fifth frame received by the second communication unit includes the second specific field, the second data included in the second specific field is stored in the first storage unit, and the fifth frame is transmitted by the first communication unit as the sixth frame. (h) If the fifth frame received by the second communication unit does not include the second specific field, the second specific field including the second data stored in the first storage unit is generated and added to the fifth frame, and the fifth frame with the added second specific field is transmitted by the first communication unit as the sixth frame. The communication system according to claim 1.

3. The first specific field includes, as first data, information indicating the state of the first device. The communication system according to claim 1 or 2.

4. The second specific field includes, as the second data, information indicating the state of the second device. The communication system according to claim 2.

5. The aforementioned first specific field is, The first data includes command data that includes instructions from the first device to the second device, The first frame mentioned above is, Further including a first sequence number assigned by the first device, The previous second frame was, Further including the first sequence number, The first control unit is, When storing the first data contained in the first specific field of the first frame in the first storage unit, the first sequence number contained in the first frame is stored in the first storage unit in association with the command data. Furthermore, if the first specific field is deleted from the first frame, the first sequence number included in the first frame is changed to the first sequence number stored in the first storage unit in association with the command data. The second control unit is, When storing the first data contained in the first specific field in the second storage unit, the first sequence number contained in the second frame is associated with the command data and stored in the second storage unit. Furthermore, when generating the first specific field and adding it to the second frame, the first specific field, which includes the command data stored in the second storage unit in association with the first sequence number included in the second frame, is generated and added to the second frame. The communication system according to claim 1 or 2.

6. The second specific field is, The second data includes response data including a response from the second device to the first device, The aforementioned fourth frame is, Further including a second sequence number assigned by the second device, The aforementioned fifth frame is, Further including a second sequence number, The second control unit is, When storing the second data contained in the second specific field of the fourth frame in the second storage unit, the second sequence number contained in the fourth frame is stored in the second storage unit in association with the response data. Furthermore, if the second specific field is deleted from the fourth frame, the second sequence number included in the fourth frame is changed to the second sequence number stored in the second storage unit in association with the second sequence number. The first control unit is, When storing the second data contained in the second specific field in the first storage unit, the second sequence number contained in the fifth frame is associated with the response data and stored in the first storage unit. Furthermore, when generating the second specific field and adding it to the second frame, the second specific field is generated and added to the second frame, including the response data stored in the second storage unit in association with the second sequence number included in the second frame. The communication system according to claim 2.

7. A communication device which is a first communication device that is connected to a first device and is also connected wirelessly to a second communication device which is connected to a second device, A first communication unit that receives a first frame from the first device, First memory unit and, A second communication unit that transmits a second frame to the second device via wireless communication, The first control unit, (a) If the first data included in the first specific field of the first frame received by the first communication unit is not stored in the first storage unit, the first data is stored in the first storage unit, and the first frame is transmitted by the second communication unit as the second frame. (b) If the first data contained in the first specific field of the first frame received by the first communication unit is stored in the first storage unit, the first specific field is deleted from the first frame, and the first frame from which the first specific field has been deleted is transmitted by the second communication unit as the second frame. It comprises a first control unit. Communication device.

8. A communication device which is a second communication device that is connected to a second device and is also connected wirelessly to a first communication device which is connected to a first device, A third communication unit that receives a second frame from the first communication device via wireless communication, The second memory unit, A fourth communication unit that transmits a third frame to the second device, The second control unit, (c) If the second frame received by the third communication unit includes a first specific field, the first data included in the first specific field is stored in the second storage unit, and the second frame is transmitted by the fourth communication unit as the third frame. (d) If the second frame received by the third communication unit does not include the first specific field, the third communication unit generates the first specific field including the first data stored in the second storage unit and adds it to the second frame, and transmits the second frame with the first specific field added as the third frame. It comprises a second control unit. Communication device.

9. A control method performed by a communication system comprising a first communication device connected to a first device and a second communication device connected to a second device, The first communication device is A first communication unit that receives a first frame from the first device, First memory unit and, A second communication unit that transmits a second frame to the second device via wireless communication, It comprises a first control unit, The second communication device is A third communication unit that receives the second frame from the first communication device via wireless communication, The second memory unit, A fourth communication unit that transmits a third frame to the second device, It comprises a second control unit, The control method described above is (a) If the first control unit finds that the first data included in the first specific field of the first frame received by the first communication unit is not stored in the first storage unit, the first control unit stores the first data in the first storage unit and causes the first frame to be transmitted by the second communication unit as the second frame. (b) If the first control unit has the first data contained in the first specific field of the first frame received by the first communication unit stored in the first storage unit, it deletes the first specific field from the first frame and causes the second communication unit to transmit the first frame from which the first specific field has been deleted as the second frame. (c) If the second frame received by the third communication unit includes the first specific field, the second control unit stores the first data included in the first specific field in the second storage unit and causes the fourth communication unit to transmit the second frame as the third frame. (d) If the second frame received by the third communication unit does not contain the first specific field, the second control unit generates the first specific field containing the first data stored in the second storage unit and adds it to the second frame, and causes the second frame with the first specific field added to be transmitted as the third frame. Control method.

10. A control method for a communication device which is a first communication device connected to a first device and also connected wirelessly to a second communication device which is connected to a second device, A first communication unit that receives a first frame from the first device, First memory unit and, A second communication unit that transmits a second frame to the second device via wireless communication, It comprises a first control unit, The first control unit is, (a) If the first data included in the first specific field of the first frame received by the first communication unit is not stored in the first storage unit, the first data is stored in the first storage unit, and the first frame is transmitted by the second communication unit as the second frame. (b) If the first data contained in the first specific field of the first frame received by the first communication unit is stored in the first storage unit, the first specific field is deleted from the first frame, and the first frame from which the first specific field has been deleted is transmitted as the second frame by the second communication unit. Control method.

11. A control method for a communication device which is a second communication device connected to a second device and also connected wirelessly to a first communication device connected to a first device, A third communication unit that receives a second frame from the first communication device via wireless communication, The second memory unit, A fourth communication unit that transmits a third frame to the second device, It comprises a second control unit, The second control unit is, (c) If the second frame received by the third communication unit includes a first specific field, the first data included in the first specific field is stored in the second storage unit, and the second frame is transmitted by the fourth communication unit as the third frame. (d) If the second frame received by the third communication unit does not include the first specific field, the third communication unit generates the first specific field including the first data stored in the second storage unit and adds it to the second frame, and transmits the second frame with the first specific field added as the third frame. Control method.

12. A program that causes a computer to execute the control method described in claim 10.

13. A program that causes a computer to execute the control method described in claim 11.

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