Relay device and relay program

Abstract

When respective communications between a plurality of masters and a plurality of slaves are relayed at the same degree of priority, communication by a master that performs high-priority communication may be delayed. A relay device (1) relays communication between a first master (M1) and a plurality of slaves "SLG" and between a second master (M2) and the plurality of slaves "SLG". The relay device (1) includes a first communication port, a second communication port, a third communication port, and a control unit. The first communication port is connected to the first master (M1). The second communication port is connected to the second master (M2). The third communication port is connected with the plurality of slaves (SLG). The control unit (19) relays first communication between the first master (M1) and the plurality of slaves (SLG). The control unit (19) relays second communication between the second master (M2) and the plurality of slaves (SLG). The control unit (19) relays the first communication with priority over the second communication.

Description

Relay device and relay program

[0001] Relates to a relay device and a relay program.

[0002] As shown in Patent Document 1 (Japanese Patent No. 6321393), there is a technology for relaying communication between a plurality of masters and a plurality of slaves.

[0003] In Patent Document 1, since each communication is relayed with the same priority, there is a problem that communication by a master that performs high-priority communication may be delayed.

[0004] The relay device according to the first aspect connects a first master and a second master to a single-master / multi-slave network. The relay device relays communication between the first master and the second master and a plurality of slaves. The relay device includes a first communication port, a second communication port, a third communication port, and a control unit. The first communication port is connected to the first master. The second communication port is connected to the second master. The third communication port is connected to a plurality of slaves. The control unit relays first communication between the first master and a plurality of slaves. The control unit relays second communication between the second master and a plurality of slaves. The control unit relays the first communication with priority over the second communication.

[0005] In the relay device according to the first aspect, the control unit relays the first communication with priority over the second communication. As a result, the relay device can prevent communication by the first master, which has a high priority, from being delayed.

[0006] The relay device according to the second aspect is the relay device according to the first aspect. In communication between the first master and the second master and a plurality of slaves, the first master and the second master transmit requests to slaves included in the plurality of slaves. The control unit determines whether the communication having the request is the first communication or the second communication based on the communication port that received the request.

[0007] The relay device in the third perspective is the relay device in the first perspective, and in communication between the first master and the second master and a plurality of slaves, the first master and the second master send a request to a slave included in the plurality of slaves. The request includes equipment information of the first master or the second master that is the source of the request. The control unit determines, based on the equipment information, whether the communication with the request is a first communication or a second communication.

[0008] The relay device in the fourth perspective is one relay device from either the first or third perspective, and the plurality of slaves includes a first slave and a second slave. The first communication is completed when the first master sends a first request to the first slave and the first master receives a first response to the first request from the first slave. The second communication is completed when the second master sends a second request to the second slave and the second master receives a second response to the second request from the second slave. If the relaying of the first communication and the relaying of the second communication overlap, the control unit relays the first request and first response to complete the first communication before relaying the second request and second response.

[0009] The relay device in the fifth perspective is the relay device in the fourth perspective, and if the relaying of the first communication and the relaying of the second communication overlap, it is when the first request is received while the second request is being received, when the second response is received while the first request is being received, or when the first response is received while the second request is being received.

[0010] The relay device of the sixth perspective is a relay device of either the first or fifth perspective, further comprising a switching circuit. The switching circuit connects the first communication port and the third communication port. If the control unit is unable to relay the first or second communication due to a malfunction of the relay device, the first communication is transmitted through the switching circuit.

[0011] The relay device described in the sixth perspective, with this configuration, can maintain communication via the first master, which has a higher priority, even if a malfunction occurs in the relay device.

[0012] The relay program in the seventh perspective relays communication between a first master and a second master and multiple slaves in a relay device. The relay device connects the first master and the second master to a single-master / multi-slave network. The relay device has a first communication port, a second communication port, a third communication port, and a control unit. The first communication port is connected to the first master. The second communication port is connected to the second master. The third communication port is connected to multiple slaves. The relay program causes the relay device to function as a means comprising a first step, a second step, and a third step. The first step relays the first communication between the first master and multiple slaves. The second step relays the second communication between the second master and multiple slaves. The third step relays the first communication with higher priority than the second communication.

[0013] This figure shows a communication system with a single-master / multi-slave network. This figure shows a communication system with a second master and a relay device. This is a functional block diagram of the relay device. This is a flowchart explaining the priority relay function of the relay device. This is a flowchart explaining the priority relay function of the relay device. This is a flowchart explaining the priority relay function of the relay device.

[0014] (1) Overall configuration diagram 1 shows a communication system 80 having a single-master / multi-slave network. As shown in Figure 1, the communication system 80 has a first master M1 and a plurality of slave SLGs. The first master M1 and the plurality of slave SLGs are daisy-chained together via a communication line 90 to enable communication.

[0015] Hereafter, slave SLs included in multiple slave SLGs may be referred to as the first slave SL1 and the second slave SL2. The first slave SL1 and the second slave SL2 may be the same device or different devices. In Figure 1, the first slave SL1 and the second slave SL2 are depicted as different devices.

[0016] The first master M1 controls the first slave SL1. However, there are cases where it is desired to add control over the second slave SL2 while maintaining control over the first slave SL1 by the first master M1. In such cases, it is conceivable to provide the communication system 80 with a second master M2 to perform additional control over the second slave SL2, and a relay device 1 that connects the first master M1 and the second master M2 to a single-master / multi-slave network. Figure 2 shows a communication system 81 in which the second master M2 and the relay device 1 are provided in the communication system 80. As shown in Figure 2, the first master M1 and the relay device 1 are connected communicatively by a communication line 91. The second master M2 and the relay device 1 are connected communicatively by a communication line 92. The relay device 1 and the multiple slave SLs are daisy-chained and communicated with each other by a communication line 93.

[0017] The relay device 1 relays communication between the first master M1 and the second master M2 and the multiple slave SLGs. However, if the relay device 1 relays the communication between the first master M1 and the first slave SL1 and the communication between the second master M2 and the second slave SL2 with the same priority, there is a risk that the communication between the first master M1 and the first slave SL1, which should be maintained (prioritized), will be delayed.

[0018] Therefore, in this embodiment, the relay device 1 is configured to relay communication between the first master M1 and the first slave SL1 with priority over communication between the second master M2 and the second slave SL2.

[0019] (2) Detailed Configuration (2-1) Slave Slave SL is controlled by the first master M1 or the second master M2. Slave SL is, for example, an air conditioner, a low-temperature display case, etc.

[0020] For example, if the slave SL is an air conditioner, it constitutes a vapor compression refrigeration cycle and provides air conditioning for a target space within a building. The slave SL has an indoor unit and an outdoor unit.

[0021] The indoor unit is installed, for example, on the ceiling of the target space. The indoor unit mainly consists of an indoor heat exchanger, an indoor fan, an indoor expansion valve, an indoor control unit, and various sensors. The indoor heat exchanger performs heat exchange between the refrigerant flowing through the indoor heat exchanger and the air in the target space. The indoor fan draws air from the target space into the indoor unit, exchanges heat with the refrigerant in the indoor heat exchanger, and supplies the drawn-in air to the target space. The indoor expansion valve is a mechanism for adjusting the pressure and flow rate of the refrigerant flowing through the refrigerant circuit. The indoor control unit controls the operation of each part that makes up the indoor unit. The indoor control unit is communicated with the indoor fan, the indoor expansion valve, and various sensors. The indoor control unit has a control calculation device and a memory device. The control calculation device is a processor such as a CPU or GPU. The memory device is a storage medium such as RAM, ROM, or flash memory. The control calculation device reads a program stored in the memory device and controls the operation of each part that makes up the indoor unit by performing predetermined calculation processing according to the program. Furthermore, the control calculation unit can write calculation results to a memory device and read information stored in the memory device according to the program. The indoor control unit exchanges various information, such as control signals, signals related to measurements from various sensors, and signals related to various settings, with the outdoor control unit of the outdoor unit of the outdoor unit via a communication line.

[0022] The outdoor unit is installed, for example, on the roof of a building. The outdoor unit mainly consists of a compressor, a flow path switching valve, an outdoor heat exchanger, an outdoor expansion valve, an outdoor fan, an outdoor control unit, and various sensors. The compressor draws in low-pressure refrigerant from the suction pipe, compresses the refrigerant using a compression mechanism, and discharges the compressed refrigerant through the discharge pipe. The flow path switching valve is a mechanism that switches the flow path of the refrigerant between a first state and a second state. During cooling operation, the flow path switching valve sets the refrigerant flow path to the first state. At this time, the refrigerant discharged from the compressor flows through the refrigerant circuit in the order of outdoor heat exchanger, outdoor expansion valve, indoor expansion valve, indoor heat exchanger, and returns to the compressor. In the first state, the outdoor heat exchanger functions as a condenser, and the indoor heat exchanger functions as an evaporator. During heating operation, the flow path switching valve sets the refrigerant flow path to the second state. In this state, the refrigerant discharged from the compressor flows through the refrigerant circuit in the following order: indoor heat exchanger, indoor expansion valve, outdoor expansion valve, and outdoor heat exchanger, before returning to the compressor. In the second state, the outdoor heat exchanger functions as an evaporator, and the indoor heat exchanger functions as a condenser. The outdoor heat exchanger facilitates heat exchange between the refrigerant flowing through it and the outdoor air of the building. The outdoor expansion valve is a mechanism for regulating the pressure and flow rate of the refrigerant flowing through the refrigerant circuit. The outdoor fan supplies outdoor air to the outdoor heat exchanger. The outdoor control unit controls the operation of each component of the outdoor unit. The outdoor control unit is communicatively connected to the compressor, flow path switching valve, outdoor expansion valve, outdoor fan, and various sensors. The outdoor control unit has a control calculation device and a memory device. The control calculation device is a processor such as a CPU or GPU. The memory device is a storage medium such as RAM, ROM, or flash memory. The control arithmetic unit reads a program stored in the memory and controls the operation of each component of the outdoor unit by performing predetermined calculations according to the program. The control arithmetic unit can also write calculation results to the memory and read information stored in the memory according to the program. The outdoor control unit exchanges various information, such as control signals, signals related to measurements from various sensors, and signals related to various settings, with the indoor control unit of the indoor unit of the indoor unit via a communication line.Furthermore, the outdoor control unit exchanges various information, such as control signals, signals related to measurements from various sensors, and signals related to various settings, with the first master M1 or the second master M2 via the communication line 93.

[0023] (2-2) Master The first master M1 controls the first slave SL1. The second master M2 controls the second slave SL2. The first master M1 and the second master M2 each have a control arithmetic unit and a memory device. The control arithmetic unit is a processor such as a CPU or GPU. The memory device is a storage medium such as RAM, ROM, or flash memory. The control arithmetic unit reads a program stored in the memory device and controls the operation of each part that makes up the outdoor unit by performing predetermined arithmetic processing according to the program. The control arithmetic unit can also write the calculation results to the memory device or read information stored in the memory device according to the program. For example, if the first slave SL1 is an air conditioner, the first master M1 exchanges various information such as control signals, signals related to measurements of various sensors, and signals related to various settings with the outdoor control unit of the outdoor unit via the communication line 93.

[0024] A first communication takes place between the first master M1 and the first slave SL1. The first communication is completed when the first master M1 sends a first request REQ1 to the first slave SL1 and the first master M1 receives a first response RES1 from the first slave SL1 to the first request REQ1.

[0025] For example, if the first slave SL1 is an air conditioner, the first master M1 requests operating data from the first slave SL1 as the first request REQ1. The operating data includes, for example, the rotational speed of the indoor fan, the opening degree of the indoor expansion valve, the rotational speed of the compressor, the opening degree of the outdoor expansion valve, the rotational speed of the outdoor fan, and the measured values ​​of various sensors. When the first slave SL1 receives the first request REQ1, the indoor control unit and the outdoor control unit of the first slave SL1 cooperate to acquire the operating data. The first slave SL1 transmits the acquired operating data to the first master M1 as the first response RES1.

[0026] For example, if the first slave SL1 is an air conditioner, the first master M1 sends the target temperature of the target space to the first slave SL1 as the first request REQ1. When the first slave SL1 receives the first request REQ1, it sends ACK (ACKknowledgment) to the first master M1 as the first response RES1. The indoor control unit and outdoor control unit of the first slave SL1 cooperate to adjust the rotation speed of the indoor fan, the opening degree of the indoor expansion valve, the rotation speed of the compressor, the opening degree of the outdoor expansion valve, and the rotation speed of the outdoor fan, etc., so that the temperature of the target space becomes the target temperature included in the first request REQ1.

[0027] Similarly, a second communication takes place between the second master M2 and the second slave SL2. The second communication is completed when the second master M2 sends a second request REQ2 to the second slave SL2, and the second master M2 receives a second response RES2 to the second request REQ2 from the second slave SL2.

[0028] (2-3) Relay device Figure 3 is a functional block diagram of the relay device 1. As shown in Figure 3, the relay device 1 mainly consists of a storage unit 11, a first communication unit 141 to a third communication unit 143, and a control unit 19.

[0029] (2-3-1) Storage Unit The storage unit 11 is a storage medium such as RAM, ROM, or flash memory. The storage unit 11 stores the program to be executed by the control unit 19, and data necessary for the execution of the program.

[0030] (2-3-2) Communication Unit The first communication unit 141 is a network interface device having a first communication port P1. The first communication port P1 is connected to the first master M1 via a communication line 91. The second communication unit 142 is a network interface device having a second communication port P2. The second communication port P2 is connected to the second master M2 via a communication line 92. The third communication unit 143 is a network interface device having a third communication port P3. The third communication port P3 is connected to a plurality of slave SLGs via a communication line 93.

[0031] (2-3-3) Control Unit The control unit 19 is a processor such as a CPU or GPU. The control unit 19 reads and executes programs such as relay programs stored in the memory unit 11, and realizes various functions of the relay device 1. The control unit 19 can also write calculation results to the memory unit 11 and read information stored in the memory unit 11 according to programs such as relay programs.

[0032] The control unit 19 relays the first communication and the second communication. In particular, the control unit 19 has a priority relay function to relay the first communication with higher priority than the second communication.

[0033] (2-3-3-1) When the relaying of the first communication and the relaying of the second communication overlap, the priority relay function control unit 19 relays the first request REQ1 and the first response RES1 before relaying the second request REQ2 and the second response RES2 to complete the first communication. The relaying of the first communication and the relaying of the second communication overlap when the first request REQ1 is received while the second request REQ2 is being received, when the second response RES2 is received while the first request REQ1 is being received, or when the first response RES1 is received while the second request REQ2 is being received.

[0034] The control unit 19 determines whether the communication containing the request is a first communication or a second communication, based on the communication port from which the request was received. Specifically, if the control unit 19 receives the request via the first communication port P1, it determines that the communication containing the request is a first communication (the request is the first request, REQ1). If the control unit 19 receives the request via the second communication port P2, it determines that the communication containing the request is a second communication (the request is the second request, REQ2).

[0035] Below, the processing of the priority relay function will be explained using the flowcharts in Figures 4 to 6 for each of the three cases in which the relay of the first communication and the relay of the second communication overlap. In Figures 4 to 6, the flow of the first request REQ1 and the first response RES1 is drawn with solid lines, and the flow of the second request REQ2 and the second response RES2 is drawn with dashed lines. Also, for simplicity, it is assumed that the first request REQ1, the first response RES1, the second request REQ2, and the second response RES2 each have 8 bytes of information. This corresponds to the fact that, for example, the first request REQ1 in Figures 4 to 6 is composed of 8 blocks.

[0036] (2-3-3-1-1) When the first request is received while the second request is being received, the processing of the priority relay function in the case where the first request REQ1 is received while the second request REQ2 is being received will be explained using the flowchart in Figure 4.

[0037] As shown in step S11, the second master M2 sends the second request REQ2 to the second slave SL2.

[0038] In step S11, while the second master M2 is sending the second request REQ2 to the second slave SL2, the first master M1 sends the first request REQ1 to the first slave SL1, as shown in step S12.

[0039] In steps S11 and S12, as shown in step S13, the relay device 1 receives the first request REQ1 from the first master M1 while it is receiving the second request REQ2 from the second master M2.

[0040] After step S13 is completed, as shown in step S14, the relay device 1 transmits the received first request REQ1 to the first slave SL1 (it relays the first request REQ1 with priority).

[0041] When step S14 is completed, as shown in step S15, the relay device 1 receives the first response RES1 from the first slave SL1 and transmits the received first response RES1 to the first master M1 (relaying the first response RES1 with priority).

[0042] When step S15 is completed, as shown in step S16, the relay device 1 transmits the received second request REQ2 to the second slave SL2 (relaying the second request REQ2).

[0043] When step S16 is completed, as shown in step S17, the relay device 1 receives the second response RES2 from the second slave SL2 and transmits the received second response RES2 to the second master M2 (relaying the second response RES2).

[0044] (2-3-3-1-2) When a second response is received while receiving the first request For the case where the second response RES2 is received while the first request REQ1 is being received, the processing of the priority relaying function will be described using the flowchart of FIG. 5.

[0045] As shown in step S21, the second master M2 transmits the second request REQ2 to the second slave SL2.

[0046] When step S21 is completed, as shown in step S22, the relay device 1 receives the second request REQ2 from the second master M2 and transmits the received second request REQ2 to the second slave SL2 (relaying the second request REQ2).

[0047] When step S22 is completed, as shown in step S23, the first master M1 transmits the first request REQ1 to the first slave SL1.

[0048] In step S23, while the relay device 1 is receiving the first request REQ1 from the first master M1, as shown in step S24, the relay device 1 receives the second response RES2 from the second slave SL2.

[0049] After completing steps S23 and S24, as shown in step S25, the relay device 1 transmits the received first request REQ1 to the first slave SL1 (prioritizing the relay of the first request REQ1).

[0050] After completing step S25, as shown in step S26, the relay device 1 receives the first response RES1 from the first slave SL1 and transmits the received first response RES1 to the first master M1 (the first response RES1 is relayed with priority).

[0051] After completing step S26, as shown in step S27, the relay device 1 transmits the second response RES2 received from the second slave SL2 to the second master M2 (relaying the second response RES2).

[0052] (2-3-3-1-3) When the first response is received while the second request is being received The processing of the priority relay function when the first response RES1 is received while the second request REQ2 is being received will be explained using the flowchart in Figure 6.

[0053] As shown in step S31, the first master M1 sends the first request REQ1 to the first slave SL1.

[0054] After completing step S31, as shown in step S32, the relay device 1 transmits the received first request REQ1 to the first slave SL1 (relays the first request REQ1).

[0055] After completing step S32, as shown in step S33, the second master M2 sends the second request REQ2 to the second slave SL2.

[0056] In step S33, while the relay device 1 is receiving the second request REQ2 from the second master M2, as shown in step S34, the relay device 1 receives the first response RES1 from the first slave SL1.

[0057] After completing steps S33 and S34, as shown in step S35, the relay device 1 transmits the first response RES1 received from the first slave SL1 to the first master M1 (prioritizing the relay of the first response RES1).

[0058] After step S35 is completed, as shown in step S36, the relay device 1 transmits the received second request REQ2 to the second slave SL2 (relays the second request REQ2).

[0059] After completing step S36, as shown in step S37, the relay device 1 receives the second response RES2 from the second slave SL2 and transmits the received second response RES2 to the second master M2 (relaying the second response RES2).

[0060] (3) Features (3-1) Conventionally, there are technologies for relaying communication between multiple masters and multiple slaves. However, with conventional technologies, each communication is relayed with the same priority, which presents a problem in that communication by the master, which is performing a high-priority communication, may be delayed.

[0061] The relay device 1 of this embodiment connects a first master M1 and a second master M2 to a single-master / multi-slave network. The relay device 1 relays communication between the first master M1 and the second master M2 and the multiple slave SLs. The relay device 1 includes a first communication port P1, a second communication port P2, a third communication port P3, and a control unit 19. The first communication port P1 is connected to the first master M1. The second communication port P2 is connected to the second master M2. The third communication port P3 is connected to the multiple slave SLs. The control unit 19 relays the first communication between the first master M1 and the multiple slave SLs. The control unit 19 relays the second communication between the second master M2 and the multiple slave SLs. The control unit 19 relays the first communication with higher priority than the second communication.

[0062] In the relay device 1 of this embodiment, the control unit 19 relays the first communication with higher priority than the second communication. As a result, the relay device 1 can prevent delays in communication by the first master M1, which has a higher priority.

[0063] (3-2) In the relay device 1 of this embodiment, in communication between the first master M1 and the second master M2 and the plurality of slave SLGs, the first master M1 and the second master M2 send requests to the slave SLs included in the plurality of slave SLGs. The control unit 19 determines whether the communication with the request is a first communication or a second communication based on the communication port that received the request.

[0064] (3-3) In the relay device 1 of this embodiment, the multiple slave SLGs include a first slave SL1 and a second slave SL2. The first communication is completed when the first master M1 sends a first request REQ1 to the first slave SL1 and the first master M1 receives a first response RES1 from the first slave SL1 for the first request REQ1. The second communication is completed when the second master M2 sends a second request REQ2 to the second slave SL2 and the second master M2 receives a second response RES2 from the second slave SL2 for the second request REQ2. If the relaying of the first communication and the relaying of the second communication overlap, the control unit 19 relays the first request REQ1 and the first response RES1 before relaying the second request REQ2 and the second response RES2 to complete the first communication.

[0065] (3-4) In the relay device 1 of this embodiment, the relay of the first communication and the relay of the second communication overlap when the first request REQ1 is received while the second request REQ2 is being received, when the second response RES2 is received while the first request REQ1 is being received, or when the first response RES1 is received while the second request REQ2 is being received.

[0066] (3-5) The relay program of this embodiment relays communication between the first master M1 and the second master M2 and the multiple slave SLs in the relay device 1. The relay device 1 connects the first master M1 and the second master M2 to a single-master / multi-slave network. The relay device 1 has a first communication port P1, a second communication port P2, a third communication port P3, and a control unit 19. The first communication port P1 is connected to the first master M1. The second communication port P2 is connected to the second master M2. The third communication port P3 is connected to the multiple slave SLs. The relay program causes the relay device 1 to function as a means comprising a first step, a second step, and a third step. The first step relays the first communication between the first master M1 and the multiple slave SLs. The second step relays the second communication between the second master M2 and the multiple slave SLs. The third step is to relay the first communication with higher priority than the second communication.

[0067] In the relay program of this embodiment, the third step is to relay the first communication with higher priority than the second communication. As a result, the relay program can prevent delays in the communication by the first master M1, which has a higher priority.

[0068] (4) Modified Examples (4-1) Modified Example 1A In this embodiment, the control unit 19 determined whether the communication containing the request was a first communication or a second communication based on the communication port that received the request. However, the control unit 19 may also determine whether the communication containing the request is a first communication or a second communication based on the device information of the first master M1 or second master M2, which is the source of the request, included in the request.

[0069] The device information for the first master M1 or the second master M2 includes, for example, the identifier (ID, MAC address, etc.) of the first master M1 or the second master M2, and the model name of the first master M1 or the second master M2.

[0070] (4-2) Modification 1B In case of an abnormality in the relay device 1 or the slave SL, the relay device 1 may further include a switching circuit 18 and first to third display units 151 to 153, as shown in Figure 3.

[0071] The switching circuit 18 connects the first communication port P1 and the third communication port P3.

[0072] The first to third display units 151 to 153 are each provided near the first to third communication ports P1 to P3. In this modified example, the first to third display units 151 to 153 are displays. The first to third display units 151 to 153 may be LEDs (Light Emitting Diodes) or the like.

[0073] (4-2-1) If an abnormality occurs in the relay device, the abnormalities in relay device 1 can be a power outage in relay device 1 and a fault in control unit 19. Furthermore, the faults in control unit 19 can be a hard fault, a memory management fault, and a bus fault.

[0074] A memory management fault occurs when noise on communication lines 91-93 causes the relay device 1 to receive a frame larger than expected, and the received frame cannot fit into the frame variable inside the relay device 1. A bus fault occurs when the control unit 19 becomes unable to process internal data or instructions due to aging or external shock. A hard fault is a fault in the control unit 19 other than memory management faults and bus faults.

[0075] If the relay device 1 malfunctions and the control unit 19 is unable to relay the first or second communication, the first communication will be transmitted through the switching circuit 18. In other words, if the relay device 1 malfunctions and the control unit 19 is unable to relay the first or second communication, the control unit 19 will activate the switching circuit 18 and relay only the first communication. At this time, the control unit 19 may display on each of the first to third display units 151 to 153 that a malfunction has occurred in the relay device 1. The control unit 19 may also notify the administrator of the communication system 81 of the malfunction in the relay device 1 via email or other means.

[0076] As a result, even if a malfunction occurs in the relay device 1, the relay device 1 can maintain communication via the first master M1, which has a higher priority.

[0077] If the malfunction of relay device 1 is due to a power outage to relay device 1, the control unit 19 periodically checks whether the power has been restored. If the power has been restored, the control unit 19 disables the switching circuit 18 and resumes relaying of the first and second communications.

[0078] If the malfunction in relay device 1 is a memory management fault, the control unit 19 periodically checks whether it can relay the first and second communications. If it can relay the first and second communications, the control unit 19 disables the switching circuit 18 and resumes relaying the first and second communications.

[0079] If the malfunction in relay device 1 is a hard fault or a bus fault, since hard faults and bus faults are internal failures and it is not expected that relaying of the first and second communications will resume, the control unit 19 maintains the state in which the switching circuit 18 is enabled.

[0080] (4-2-2) If a slave malfunction occurs, the control unit 19 determines that a malfunction has occurred in a specific slave SL if it does not receive a response from that specific slave SL, or if it receives multiple abnormal responses in a row from that specific slave SL.

[0081] If the control unit 19 determines that a specific slave SL has malfunctioned, it stops relaying to that specific slave SL. At this time, the control unit 19 may display on the third display unit 153 that a malfunction has occurred in the specific slave SL. The control unit 19 may also notify the administrator of the communication system 81 of the malfunction in the specific slave SL via email or other means.

[0082] The control unit 19 periodically sends a request to a specific slave SL to check whether the abnormality in the specific slave SL has been resolved. If the abnormality in the specific slave SL has been resolved, the control unit 19 resumes relaying to the specific slave SL.

[0083] (4-3) Although embodiments of the present disclosure have been described above, it will be understood that various modifications to the form and details are possible without departing from the spirit and scope of the present disclosure as described in the claims.

[0084] 1. Relay device 18. Switching circuit M1, M2 First master, second master P1 to P3 First communication port to third communication port REQ1, REQ2 First request, second request RES1, RES2 First response, second response SL, SL1, SL2 Slave, first slave, second slave SLG Multiple slaves

[0085] Patent No. 6321393

Claims

1. A relay device (1) for relaying communication between a first master (M1) and a second master (M2) in a single-master / multi-slave network, the relay device (1) comprising: a first communication port (P1) connected to the first master; a second communication port (P2) connected to the second master; a third communication port (P3) connected to the multiple slaves; and a control unit, wherein the control unit relays first communication between the first master and the multiple slaves, relays second communication between the second master and the multiple slaves, and relays the first communication with priority over the second communication.

2. In communication between the first master and the second master and the plurality of slaves, the first master and the second master send a request to a slave (SL) included in the plurality of slaves, and the control unit determines, based on the communication port that received the request, whether the communication having the request is the first communication or the second communication, according to claim 1 (1).

3. In communication between the first master and the second master and the plurality of slaves, the first master and the second master send a request to a slave (SL) included in the plurality of slaves, the request includes equipment information of the first master or the second master that is the source of the request, and the control unit determines, based on the equipment information, whether the communication having the request is a first communication or a second communication, the relay device (1) according to claim 1.

4. The relay device (1) according to any one of claims 1 to 3, wherein the plurality of slaves include a first slave (SL1) and a second slave (SL2), the first communication is completed when the first master sends a first request (REF1) to the first slave and the first master receives a first response (RES1) to the first request from the first slave, the second communication is completed when the second master sends a second request (REF2) to the second slave and the second master receives a second response (RES2) to the second request from the second slave, and the control unit, if the relaying of the first communication and the relaying of the second communication overlap, relays the first request and the first response to complete the first communication before relaying the second request and the second response.

5. The relay device (1) according to claim 4, in which case the relay of the first communication and the relay of the second communication overlap, if the first request is received while the second request is being received, if the second response is received while the first request is being received, or if the first response is received while the second request is being received.

6. A relay device (1) according to any one of claims 1 to 5, further comprising a switching circuit (18) connecting the first communication port and the third communication port, wherein if the control unit is unable to relay the first communication or the second communication due to a malfunction of the relay device, the first communication is performed through the switching circuit.

7. A relay program for relaying communication between a first master (M1) and a second master (M2) in a relay device (1) connecting a first master (M1) and a second master (M2) to a single-master / multi-slave network, wherein the relay device comprises: a first communication port (P1) connected to the first master; a second communication port (P2) connected to the second master; a third communication port (P3) connected to the multiple slaves; and a control unit, and the relay program causes the relay device to function as a means comprising: a first step of relaying a first communication between the first master and the multiple slaves; a second step of relaying a second communication between the second master and the multiple slaves; and a third step of relaying the first communication with priority over the second communication.

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