Data transfer system and method

Abstract

To reduce communication delay in remote control.SOLUTION: Provided are first and second transfer parts for performing data transfer via a network between first and second memory areas at a prescribed transfer period. A control device for a controlled device reads a factor dataset from the second memory area in control for each prescribed control period, and writes a control dataset based on the factor dataset to the second memory area. In factor transfer for each prescribed transfer period, the factor dataset is transferred to the second memory area from the first memory area by the first and second transfer parts, and in control transfer for each prescribed transfer period, the control dataset is transferred to the first memory area from the second memory area. The network has a different delay time depending on a transfer period, the prescribed transfer period is a period shorter than the prescribed control period, and is any one of transfer periods belonging to a tolerable delay time.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention generally relates to data transfer.

Background Art

[0002] For example, at a production site, dust and the like are removed or a power source for a robot arm or the like is provided by discharging compressed air through a pipe network. At such a production site, a plurality of (or one) air compressors for compressing air and a receiver tank for receiving the compressed air from those air compressors and sending it to the pipe network are provided.

[0003] An air compressor is generally a device with high power consumption. Therefore, a production site is further provided with a unit control panel. The unit control panel controls the number of air compressors to be driven and their output based on the pressure of the receiver tank.

[0004] Instead of installing a unit control panel at the production site, it is conceivable to control the air compressor from a remote control device (typically a server). As a technology related to remote control, for example, there is the technology disclosed in Patent Document 1.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] An air compressor is an example of a controlled device. In the control of a controlled device, the control device generally periodically receives a factor dataset, determines a control dataset based on the factor dataset, and transmits the determined control dataset. The factor dataset includes factor data for each factor that may affect the control dataset, and for each factor, the factor data includes the value obtained for that factor. The control dataset includes control data for each controlled device, and for each controlled device, the control data includes control parameter values ​​for each of one or more control parameter items.

[0007] Delays in the communication of factor datasets and control datasets degrade the quality of control. Therefore, reducing communication delays in remote control is necessary to improve the quality of remote control. [Means for solving the problem]

[0008] The system includes a first transfer unit and a second transfer unit that perform factor transfers and control transfers at predetermined transfer cycles. The first memory area and the first transfer unit are provided in at least one of the one or more controlled devices, or in a first data transfer device connected to the one or more controlled devices. The second memory area and the second transfer unit are provided in the control unit of the one or more controlled devices, or in a second data transfer device connected to the control unit. The first memory area includes a first transmission area and a first reception area. The second memory area includes a second transmission area and a second reception area. The factor dataset is written to the first transmission area.

[0009] The start of a predetermined transfer cycle for factor transfer and the start of a predetermined transfer cycle for control transfer are asynchronous. In factor transfers at predetermined transfer cycles, the first transfer unit reads a factor dataset from the first transmission area, transfers the read factor dataset to the second transfer unit via the network, and the second transfer unit writes the factor dataset to the second reception area. In control transfers at predetermined transfer cycles, the second transfer unit reads a control dataset from the second transmission area, transfers the read control dataset to the first transfer unit via the network, and the first transfer unit writes the control dataset to the first reception area.

[0010] The control unit in the control device performs control at a predetermined control cycle, and the control at each predetermined control cycle includes reading a factor dataset from a second receiving area, determining control data for each controlled device based on the read factor dataset, and writing the control dataset containing the determined control data for each controlled device to a second transmitting area.

[0011] Networks have a characteristic where the delay time differs depending on the transfer period. Both the predetermined transfer period for factor transfers and the predetermined transfer period for control transfers are shorter than the predetermined control period and belong to one of the transfer periods that fall within the allowable delay time. [Effects of the Invention]

[0012] According to the present invention, communication delays in remote control can be reduced. [Brief explanation of the drawing]

[0013] [Figure 1] An example of the overall system configuration, including the data transfer system according to the first embodiment, is shown. [Figure 2] This diagram schematically illustrates the process, including data transfer. [Figure 3] This shows an example of network characteristics as a relationship between the transfer cycle and delay time. [Figure 4] This shows an example of the processing flow performed by the control unit. [Figure 5] This shows an example of the transmission process performed by the transfer unit. [Figure 6] An example of the overall system configuration, including the data transfer system according to the second embodiment, is shown. [Modes for carrying out the invention]

[0014] In the following description, "interface device" may refer to one or more interface devices. These one or more interface devices may be one or more identical communication interface devices or two or more different communication interface devices.

[0015] Furthermore, in the following explanation, "memory" refers to one or more memory devices, which are typically main memory devices. At least one memory device in memory may be a volatile memory device or a non-volatile memory device.

[0016] Furthermore, in the following explanation, "persistent storage device" refers to one or more persistent storage devices. Persistent storage devices are typically non-volatile storage devices (e.g., auxiliary storage devices), specifically, for example, HDDs (Hard Disk Drives) or SSDs (Solid State Drives).

[0017] Furthermore, in the following explanation, "storage device" may refer to at least memory, including both memory and persistent storage.

[0018] Also, in the following description, a "processor" may be one or more processor devices. At least one processor device may typically be a microprocessor device such as a CPU (Central Processing Unit), but may also be other types of processor devices such as a GPU (Graphics Processing Unit). At least one processor device may be single-core or multi-core. At least one processor device may be a processor core. At least one processor device may also be a processor device in a broad sense such as a hardware circuit (e.g., FPGA (Field-Programmable Gate Array), CPLD (Complex Programmable Logic Device), or ASIC (Application Specific Integrated Circuit)) that performs part or all of the processing.

[0019] Also, in the following description, when the processing is described with "program" as the subject, the program is executed by a processor to perform the defined processing while appropriately using a storage device and / or an interface device, etc., so the subject of the processing may be a processor (or a device such as a controller having the processor). The program may be installed from a program source into a device such as a computer. The program source may be, for example, a program distribution server or a computer-readable (e.g., non-temporary) recording medium. Also, in the following description, two or more programs may be realized as one program, or one program may be realized as two or more programs.

[0020] In the following description, the function may be described in terms of a "yyy unit", but the function may be realized by one or more computer programs being executed by a processor. When the function is realized by the program being executed by the processor, since the defined processing is performed while appropriately using a storage device and / or an interface device, etc., the function may be regarded as at least part of the processor. The processing described with the function as the subject may also be the processing performed by the processor or a device having the processor. The description of each function is an example, and a plurality of functions may be combined into one function, or one function may be divided into a plurality of functions.

[0021] In the following description, when describing elements of the same kind without distinction, a common part of the reference signs may be used, and when describing elements of the same kind while distinguishing them, reference signs may be used.

[0022] Hereinafter, some embodiments of the present invention will be described. [First Embodiment]

[0023] FIG. 1 shows a configuration example of an entire system including a data transfer system according to the first embodiment.

[0024] A plurality of air compressors 130 (130A, 130B,...) are controlled by a control device 110 via a wide-area wireless network 100. The air compressor 130 is an example of industrial equipment. The industrial equipment is an example of a controlled device. The wide-area wireless network 100 is an example of a network and may be a 4G, LTE or 5G wireless network. Further, a receiver tank 140 that receives compressed air from the air compressor 130 and sends it to a pipe network not shown is provided.

[0025] The control device 110 comprises an interface device 111, a storage device 112, and a processor 113 connected thereto. The interface device 111A includes a device that communicates with a second data transfer device 120B. The storage device 112 stores control period data 154 representing the control period T1. The storage device 112 also stores one or more computer programs. These one or more computer programs include a control program for realizing the control unit 151. The control unit 151 is realized when the processor 113 executes these one or more computer programs.

[0026] The system includes a first transfer unit 161A and a second transfer unit 161B that perform data transfer via a wide-area wireless network 100 at a predetermined transfer cycle T2. The first memory area 163A and the first transfer unit 161A are provided in a first data transfer device 120A connected to a plurality of air compressors 130 and a receiver tank 140. The second memory area 163B and the second transfer unit 161B are provided in a second data transfer device 120B connected to a control device 110.

[0027] In other words, this embodiment includes first and second data transfer devices 120A and 120B for transferring data between the control device 110 and the air compressor 130.

[0028] The first data transfer device 120A may be a relay device and comprises an interface device 121A, a storage device 122A, and a processor 123A connected thereto. The interface device 121A includes a device for communicating with a plurality of air compressors 130, a device for communicating with a receiver tank 140 (for example, a pressure sensor provided in the receiver tank 140), and a device for communicating with the second data transfer device 120B via a wide-area wireless network 100. The storage device 122A includes a memory having a first memory area 163A. The storage device 122A also stores transfer period data 164A representing the transfer period T2. The storage device 122A also stores a plurality of computer programs. These plurality of computer programs include a first transfer program for realizing the first transfer unit 161A and a first IF (interface) program for realizing the first IF (interface) unit 162A. The processor 123A executes the multiple computer programs, thereby realizing the first transfer unit 161A and the first IF unit 162A.

[0029] The second data transfer device 120B may be a relay device and comprises an interface device 121B, a storage device 122B, and a processor 123B connected thereto. The interface device 121B includes a device that communicates with the first data transfer device 120A via the wide-area wireless network 100, and a device that notifies the control device 110. The storage device 122B includes a memory having a second memory area 163B. The storage device 122B also stores transfer period data 164B representing the transfer period T2. The storage device 122B also stores a plurality of computer programs. These plurality of computer programs include a second transfer program for realizing the second transfer unit 161B and a second IF program for realizing the second IF unit 162B. The processor 123B executes these plurality of computer programs to realize the second transfer unit 161B and the second IF unit 162B.

[0030] Figure 2 schematically illustrates the processing flow, including data transfer.

[0031] The first and second memory areas 163A and 163B may be called a wide-area shared memory area or a transfer memory, respectively. The first memory area 163A includes a first transmission area 63Aa and a first reception area 63Ab. The second memory area 163B includes a second reception area 63Bb and a second transmission area 63Ba.

[0032] The first IF unit 162A includes a first transmission IF unit 62Aa and a first reception IF unit 62Ab. The first transmission IF unit 62Aa receives a factor dataset and writes it to the first transmission area 63Aa. The first reception IF unit 62Ab writes a control dataset to the first reception area 63Ab and outputs the control data to the air compressor 130.

[0033] The second IF unit 162B includes a second receiving IF unit 62Bb and a second transmitting IF unit 62Ba. The second receiving IF unit 62Bb reads a factor dataset from the second receiving area 63Bb and outputs the factor dataset to the control unit 151. The second transmitting IF unit 62Ba receives a control dataset and writes it to the second transmitting area 63Ba.

[0034] The first transfer unit 161A includes a first transmitter 61Aa and a first receiver 61Ab. The second transfer unit 161B includes a second receiver 61Bb and a second transmitter 61Ba. Factor transfer (which may also be called an uplink transfer) takes place between the first transmitter 61Aa and the second receiver 61Bb at transfer cycles T2, that is, the first transmitter 61Aa starts factor transfer at transfer cycles T2. Control transfer (which may also be called a downlink transfer) takes place between the second transmitter 61Ba and the first receiver 61Ab at transfer cycles T2, that is, the second transmitter 61ba starts control transfer at transfer cycles T2. The start of the factor transfer transfer cycle T2 and the start of the control transfer transfer cycle T2 are asynchronous.

[0035] The first transmission IF unit 62Aa receives the factor dataset from the factor data source and writes the factor dataset to the first transmission area 63Aa. This process may be performed with a period T3. The period T3 may be longer than the transfer period T2 and may be the same as or different from the control period T1. Alternatively, this process may be performed aperiodically instead of with a period T3.

[0036] The "factor dataset" includes factor data for each factor that may affect the control dataset. For each factor, the factor data includes the values ​​obtained for that factor. An example of a factor is the pressure of the receiver tank 140. Other examples of factors may include the ON or OFF state of the air compressor 130, the motor speed of the air compressor 130, or the power consumption. A "factor data source" is a source of factor data and includes, for example, the receiver tank 140 (e.g., the pressure sensor of the receiver tank 140). The factor data source may also include the air compressor 130 (e.g., a sensor provided on the air compressor 130).

[0037] Both the factor transfer period T2 and the control transfer period T2 are shorter than the control period T1. Typically, the lengths of the factor transfer period T2 and the control transfer period T2 are the same, but they may be different.

[0038] In factor transfer, the following processes are performed: The first transmitting unit 61Aa reads the factor dataset from the first transmitting area 63Aa and transfers the read factor dataset to the second receiving unit 61Bb. The second receiving unit 61Bb writes the factor dataset to the second receiving area 63Bb. In a single factor transfer, all data necessary for determining the control dataset for one control cycle (all of the factor dataset) may be transferred. Alternatively, all factor data may be sent with each transfer cycle T2, or only factor data that has changed from the factor data transmitted in the previous transfer cycle T2 may be transferred.

[0039] In a control transfer, the following processes are performed: The second transmitter 61Ba reads the control data set from the second transmission area 63Ba and transfers the read control data set to the first receiver 61Ab. The first receiver 61Ab writes the control data set to the first receiver area 63Ab.

[0040] For both factor transfers and control transfers within a single period, the size of the data being transferred (e.g., maximum size) may be predetermined.

[0041] The control unit 151 in the control device 110 performs control in a control cycle T1 (an example of a predetermined control cycle). Control for each control cycle T1 includes reading a factor dataset from the second receiving area 63Bb, determining control data for each air compressor 130 based on the read factor dataset, and writing the control dataset containing the determined control data for each air compressor 130 to the second transmitting area 63Ba. Data I / O (Input / Output) of the control unit 151 to the second transmitting area 63Ba is performed via the second transmitting IF unit 62Ba. The "control dataset" includes control data for each air compressor 130, and for each air compressor 130, the control data includes control parameter values ​​for each of one or more control parameter items. The control parameter values ​​may be, for example, ON or OFF of the air compressor 130, and the motor rotation speed of the air compressor 130. Furthermore, the air compressor 130 may be a constant-speed machine (without an inverter) in which the motor rotation speed is constant and only ON or OFF is controlled, or a variable-speed machine (with an inverter) in which the motor rotation speed is variable.

[0042] The control dataset is transferred from the second transmission area 63Ba to the first receiving area 63Ab by the second transmission unit 61Ba and the first receiving unit 61Ab. For each air compressor 130, a control command is transmitted to the air compressor 130 from the first receiving IF unit 62Ab. The control command is associated with the control data in the control dataset stored in the first receiving area 63Ab. The air compressor 130 performs processing according to the control command (e.g., generating compressed air). For each air compressor 130, the control command may be generated in the remote control device 110 (i.e., by the control unit 151) or in the first data transfer device 120A (e.g., by the first receiving IF unit 62Ab or another function (e.g., another control unit)). At cycle T4, a control command is transmitted to each air compressor 130. The period T4 may be longer than the transfer period T2, and may be the same as or different from the control period T1.

[0043] The first memory area 163A and the first transfer unit 161A may be provided in at least one air compressor 130 instead of the first data transfer device 120A. For example, if the air compressor 130 is connected to the first data transfer device 120A, the first memory area 163A and the first transfer unit 161A may be provided in the first data transfer device 120A. If the air compressor 130 is not connected to the first data transfer device 120A, the first memory area 163A and the first transfer unit 161A may be provided in the air compressor 130.

[0044] The second memory area 163B and the second transfer unit 161B may be provided in the control device 110. For example, if the control device 110 is not connected to the second data transfer device 120B, the second memory area 163B and the second transfer unit 161B may be provided in the control device 110.

[0045] Figure 3 shows an example of network characteristics as a relationship between the transfer period and delay time.

[0046] One of the network characteristics of a network like wide-area wireless network 100 is the relationship between the transmission cycle and delay time. The graph shown in Figure 3 illustrates an example of this relationship. The horizontal axis corresponds to the transmission cycle, and the vertical axis corresponds to the average value and standard deviation of the delay time for unidirectional transmission (upstream or downstream transmission).

[0047] As illustrated in Figure 3, the delay time differs depending on the transmission period. The optimal transmission period is one that satisfies at least (x) (preferably both (x) and (y)) below. (x) The average value of the delay time is less than or equal to the first threshold. The first threshold may be, for example, a predetermined value, or a value determined based on the average value for each transfer cycle represented in the network characteristics (a relative value). The average value may be an example of a statistical value. (y) The standard deviation of the delay time is less than or equal to the second threshold. The second threshold may be, for example, a predetermined value, or a value (relative value) determined based on the standard deviation for each transfer cycle represented in the network characteristics.

[0048] The transfer period T2 is a period shorter than the control period T1 and falls within the allowable delay time (for example, the area enclosed by the dashed frame in Figure 3). In other words, the transfer period T2 is a transfer period that falls within the allowable delay time among the delay times corresponding to transfer periods shorter than the control period T1. This makes it possible to reduce the communication delay in remote control.

[0049] Furthermore, the size of the data transmitted and received by the first transfer unit 161A and the second transfer unit 161B during data transfer with a transfer cycle T2 may be predetermined. Therefore, the number of data transfers in a given period decreases as the transfer cycle T2 lengthens, and consequently, the total amount of data transferred during that period decreases as the transfer cycle T2 lengthens. Thus, the transfer cycle T2 may be the longest transfer cycle among multiple transfer cycles that belong to the allowable delay time.

[0050] Furthermore, while the network may be a wired network, this embodiment includes a wireless network. With a wireless network, the differences in network characteristics (relationship between transfer cycle and delay time) are considered to be greater than with a wired network, depending on the location where network characteristics are observed and the QoS policy for data transfer (for example, rapidly transferring packets from user terminals with high communication frequency and transferring packets from user terminals with low communication frequency in batches). Even when remote control is performed via a wireless network, communication delay can be reduced.

[0051] Furthermore, various types of devices can be used as controlled devices. Different types of devices may be mixed among multiple controlled devices. In this embodiment, at least one of the one or more controlled devices is an air compressor 130 (or other industrial equipment). Industrial equipment such as an air compressor 130 needs to have shorter control cycles and delay times compared to other types of controlled devices (e.g., building air conditioning systems). Specifically, if the control cycle of industrial equipment is long, there is a high possibility of vibration occurring. Therefore, the control cycle T1 needs to be relatively short. For this reason, in remote control of industrial equipment via a wireless network, the delay of the wireless network becomes a problem. In this embodiment, this problem is solved.

[0052] Furthermore, the data transfer system according to this embodiment may also be called a remote control system that includes a control unit 151 in addition to the first and second transfer units 161A and 161B, and performs remote control of multiple air compressors 130.

[0053] Figure 4 shows an example of the processing flow performed by the control unit 151.

[0054] The control unit 151 determines whether or not the control period T1 represented by the control period data 154 has started (S401).

[0055] If the result of the determination in S401 is true (S401: Yes), the control unit 151 reads the factor dataset from the second receiving area 63Bb and stores the read factor dataset in the storage device 112 (S402). The factor dataset read here is, for example, the factor dataset necessary for determining the control dataset for the current control period T1, and may be, for example, a factor dataset that has not yet been read from the second memory area 163B.

[0056] The control unit 151 determines the control dataset based on the factor dataset read in S402 (S403). For example, in S403, for each air compressor 130, control parameter values ​​are determined for each of several control parameter items, including whether to operate or not (ON / OFF) and the motor rotation speed if operating. Control data including the determined control parameter values ​​is generated for each air compressor 130.

[0057] The control unit 151 determines the sequence ID (S404). The sequence ID may be the sequential number of the current control cycle T1, and may be updated each time the control cycle T1 ends or begins.

[0058] The control unit 151 associates the sequence ID determined in S404 with the control dataset determined in S403, and writes the control dataset associated with the sequence ID to the second transmission area 63Ba (S405). For example, the control dataset may be written sequentially to the second transmission area 63Ba, and the sequence ID may be written at the start and end of the writing of the control dataset.

[0059] The sequence ID may also be assigned when writing to the first transmission area 63Aa of the factor dataset. Details will be described later.

[0060] Figure 5 shows an example of the transmission process performed by the transfer unit 161. Here, "transfer unit 161" is a collective term for the first and second transfer units 161A and 161B. In other words, both the first and second transfer units 161A and 161B perform the processing shown in Figure 5. Also, in the explanation referring to Figure 5, "memory area 163" is a collective term for the first and second memory areas 163A and 163B.

[0061] The transfer unit 161 determines whether or not the transfer period T2 represented by the transfer period data 164 has started (S501).

[0062] If the result of the determination in S501 is true (S501: Yes), the transfer unit 161 determines whether or not data simultaneity is maintained (S502). Here, "data simultaneity is maintained" means that the same sequence ID is associated with the beginning and end of the dataset to be read (factor dataset or control dataset) (the sequence ID at the start of writing and the sequence ID at the end of writing are the same). The determination in S502 is an example of data simultaneity determination.

[0063] If the result of the determination in S502 is true (S502: Yes), the transfer unit 161 determines whether the sequence ID associated with the dataset to be read this time is the updated sequence ID (i.e., whether it is a different sequence ID from the sequence ID associated with the dataset to be read in the previous turn) (S503). The determination in S503 is an example of an ID update determination.

[0064] If the result of the determination in S503 is true (S503: Yes), the transfer unit 161 reads the dataset to be read from the memory area 163 and transfers the read dataset (S503).

[0065] If the result of the judgment in S503 is false (S503: No), the transfer unit 161 transfers small-sized data (an example of dummy data of a predetermined size) (S505). The small-sized data may be smaller than the maximum size of data transferred in a single transfer. According to the network characteristics illustrated in Figure 3, if the transfer cycle T2 becomes longer, the delay time may increase, but if the maximum size data is transferred every transfer cycle T2, the total amount of data communication will increase. In this embodiment, if there is no data to read, small-sized data is transferred, so both prolonged delay time and an increase in the total amount of data communication can be avoided. An example of a case where "there is no data to read" may occur is when the transfer cycle T2 is sufficiently shorter than the control cycle T1.

[0066] If the result of the S502 judgment is false (S502: No), the transfer unit 161 transfers the dataset that was read in the previous round, or small-sized data (S506).

[0067] The above is a description of the first embodiment.

[0068] Furthermore, the transfer unit 161 (the second receiving unit 61Bb or the first receiving unit 61Ab) may discard the received data if it is small in size (it may not need to write it to the memory area 163).

[0069] Furthermore, at least one of the determinations in S502 and S503 may be performed for both factor transfer and control transfer, or for only one of them.

[0070] Furthermore, if communication via the wide-area wireless network becomes impossible (or if the communication quality deteriorates to a predetermined quality or lower), control (for example, control of the number of operating air compressors 130) may be maintained by one of the following methods. The first data transfer device 120A has a separate control unit, which controls the air compressors 130A, 130B, ... The separate control unit may perform control at each control cycle T1, and this control may include reading out the factor dataset and determining the control dataset. Air compressor 130A is the master device and the other air compressors 130 are slave devices, and control may be performed based on so-called master-slave communication. Each air compressor 130 is configured with autonomous control data, such as target values, and each air compressor 130 may perform autonomous control based on the autonomous control data configured for that air compressor 130.

[0071] Furthermore, the factor dataset written to the first transmission area 63Aa in period T3 may be transferred entirely in a single factor transfer. Also, for each of periods T1, T2, and T4 (i.e., for periodic readouts), in addition to the data read out in the current period, the data read out in the previous period may be present in the source memory area. At least one of the following (p) and (q) may be adopted. (p) The factor dataset may be acquired at period T3 and written to the first transmission area 63Aa. Periods T3 and T2 are asynchronous, and therefore, data reading from the first transmission area 63Aa for factor transfer at period T2 may begin before the entire factor dataset has been written to the first transmission area 63Aa at period T3. (q) The factor dataset transferred in period T2 is written to the second receiving area 63Bb. Periods T2 and T1 are asynchronous, and therefore, before the entire factor dataset has been written to the second receiving area 63Bb in period T2, reading of the factor dataset from the second receiving area 63Bb for control purposes may begin in period T1.

[0072] In both (p) and (q), according to one comparative example, data simultaneity may not be guaranteed. For example, while the factor dataset is being written to the first transmission area 63Aa in the current period T3, data reading may begin from the first transmission area 63Aa for factor transfer in the current period T2.

[0073] Therefore, in this embodiment, in order to guarantee data simultaneity, a sequence ID corresponding to the dataset (corresponding to the order of the dataset) is assigned to the dataset written to the memory area 163. The sequence ID is assigned to at least the beginning and end of the dataset. Multiple sequence IDs assigned to the same dataset (in this case, the sequence IDs at the beginning and end) are the same ID. That is, the same sequence ID is assigned in one cycle. For example, the sequence ID may be recorded at the beginning and end of the area containing the area on which the dataset is written, and the sequence ID at the beginning may be updated when writing of the dataset begins, and the sequence ID at the end may be updated when writing of the dataset ends. For example, at least one of the following may be performed. When writing the factor dataset to the first transmission area 63Aa during period T3, the first transmission IF unit 62Aa writes the sequence ID corresponding to the current period to the first transmission area 63Aa, and then writes the factor dataset to the first transmission area 63Aa. After writing the factor dataset, the first transmission IF unit 62Aa writes the trailing sequence ID to the first transmission area 63Aa. When writing the control dataset to the second transmission area 63Ba during period T1, the second transmission IF unit 62Ba writes the sequence ID corresponding to the current period to the second transmission area 63Ba, and then writes the control dataset to the second transmission area 63Ba. After writing the control dataset, the second transmission IF unit 62Ba writes the trailing sequence ID to the second transmission area 63Ba.

[0074] In addition to period T2, it may also be determined whether data simultaneity is maintained for periods T1 and T4. Specifically, at least one of the following may be performed. At the start of period T1, the control unit 151 determines whether the same sequence ID is associated with the beginning and end of the factor dataset to be read (data simultaneity determination). If the result of the data simultaneity determination is true, the control unit 151 reads the factor dataset to be read from the second receiving area 63Bb and performs subsequent processing based on that factor dataset. If the result of the data simultaneity determination is false, the control unit 151 performs subsequent processing based on the factor dataset read in the previous period T1. At the start of period T4, the first receiving IF unit 62Ab determines whether the same sequence ID is associated with the beginning and end of the control dataset to be read (data simultaneity determination). If the result of the data simultaneity determination is true, the first receiving IF unit 62Ab reads the control dataset to be read from the first receiving area 63Ab and performs subsequent processing based on that control dataset. If the result of the data simultaneity determination is false, the first receiving IF unit 62Ab performs subsequent processing based on the control dataset read in the previous period T4. [Second Embodiment]

[0075] A second embodiment will be described. In this description, the differences from the first embodiment will be explained primarily, and the similarities with the first embodiment will be omitted or simplified.

[0076] Figure 6 shows an example of the overall system configuration including the data transfer system according to the second embodiment.

[0077] The first test unit 661A is provided in the first data transfer device 120A (an example of a device equipped with the first transfer unit 161A). Specifically, the first test unit 661A is realized when the processor 123A of the first data transfer device 120A executes the first test program.

[0078] Furthermore, the second test unit 661B is provided in the second data transfer device 120B (an example of a device equipped with the second transfer unit 161B). Specifically, for example, the processor 123B of the second data transfer device 120B executes the second test program, thereby realizing the second test unit 661B.

[0079] The first and second test units 661A and 661B experimentally perform the aforementioned one-way or bidirectional data transfer for each of several different transfer cycles. This identifies the network characteristics as a relationship between the network's transfer cycle and delay time. The first test unit 661A stores test result data 663A representing the identified network characteristics in the storage device 122A. Similarly, the second test unit 661B stores test result data 663B representing the identified network characteristics in the storage device 122B. Such experimental data transfers are performed periodically. Alternatively, the first and second test units 661A and 661B periodically monitor the wide-area wireless network 100 and perform the above-mentioned experimental data transfer when a specific network state is detected from the monitoring results. The first and second test units 661A and 661B determine the transfer cycle based on the identified network characteristics (the network characteristics represented by the test result data 663A and 663B). As described above, the determined transfer period is one that is shorter than the control period T1 and falls within the allowable delay time. The first and second test units 661A and 661B set the determined transfer period as the transfer period T2 (updating the transfer period T2 represented by the transfer period data 164A and 164B to the determined transfer period).

[0080] In networks (especially wireless networks), the relationship between the transfer cycle and delay time is not fixed but varies depending on the number of terminals communicating simultaneously or other factors. In this embodiment, the network characteristics are identified periodically, or when a specific network condition is detected, and the transfer cycle T2 is updated. This makes it possible to maintain a reduction in communication delay.

[0081] Although several embodiments have been described above, these are merely illustrative examples for explaining the present invention and are not intended to limit the scope of the present invention to these embodiments only. The present invention can be implemented in various other forms. For example, the present invention is suitable for controlling fluids such as gases and liquids (e.g., fluid pressure control), and the controlled device may be a device that adjusts at least one attribute of the fluid, such as pressure or temperature, based on a control command (control parameter value). [Explanation of Symbols]

[0082] 161A...First data transfer unit 161B...Second data transfer unit

Claims

1. It comprises a first transfer unit and a second transfer unit that perform factor transfers and control transfers at predetermined transfer cycles, The first memory area and the first transfer unit are provided in at least one of the one or more controlled devices, or in a first data transfer device connected to the one or more controlled devices. The second memory area and the second transfer unit are provided in the control device of the one or more controlled devices, or in the second data transfer device connected to the control device. The first memory area includes a first transmission area and a first reception area. The second memory area includes a second transmission area and a second reception area, The factor dataset is written to the first transmission area. The factor dataset includes factor data for each factor that may influence the control dataset, and for each factor, the factor data includes the values ​​obtained for that factor. The control dataset includes control data for each controlled device, and for each controlled device, the control data includes control parameter values ​​for each of one or more control parameter items. The start of the predetermined transfer period for the factor transfer and the start of the predetermined transfer period for the control transfer are asynchronous. In the factor transfer described above, the first transfer unit reads the factor dataset from the first transmission area, transfers the read factor dataset to the second transfer unit via the network, and the second transfer unit writes the factor dataset to the second reception area. In the control transfer, the second transfer unit reads the control dataset from the second transmission area, transfers the read control dataset to the first transfer unit via the network, and the first transfer unit writes the control dataset to the first reception area. The control unit in the control device performs control at a predetermined control cycle, and the control at each predetermined control cycle includes reading a factor dataset from the second receiving area, determining control data for each controlled device based on the read factor dataset, and writing the control dataset containing the determined control data for each controlled device to the second transmitting area. The aforementioned network has a network characteristic in which the delay time differs depending on the transfer cycle. Both the predetermined transfer period of the factor transfer and the predetermined transfer period of the control transfer are transfer periods that are shorter than the predetermined control period and belong to any of the allowable delay times. Data transfer system.

2. The writing of the factor dataset to the first transmission area and the reading of the factor dataset from the first transmission area for factor transfer are asynchronous. At the start and end of writing the factor dataset to the first transmission area, a sequence ID corresponding to the factor dataset is associated with the factor dataset. At each predetermined transfer cycle of the factor transfer, the first transfer unit performs a data simultaneity determination, which is a determination of whether the sequence ID at the start of writing the factor dataset and the sequence ID at the end of writing are the same. If the result of the data simultaneity determination is false, the first transfer unit transfers the factor dataset read in the previous predetermined transfer cycle, or dummy data of a predetermined size, to the second transfer unit. The data transfer system according to claim 1.

3. If the result of the data simultaneity determination is true, the first transfer unit performs an ID update determination, which is a determination of whether the sequence ID associated with the factor dataset is different between the previous predetermined transfer cycle and the current predetermined transfer cycle. If the result of the ID update determination is true, the first transfer unit transfers the factor dataset to the second transfer unit. If the result of the ID update determination is false, the first transfer unit transmits dummy data of a predetermined size to the second transfer unit. The data transfer system according to claim 2.

4. The writing of the control dataset to the second transmission area and the reading of the control dataset from the second transmission area for the control transfer are asynchronous. At the start and end of writing the control dataset to the second transmission area, a sequence ID corresponding to the control dataset is associated with the control dataset. At each predetermined transfer cycle of the control transfer, the second transfer unit performs a data simultaneity determination, which is a determination of whether the sequence ID at the start of writing the control dataset and the sequence ID at the end of writing are the same. If the result of the data simultaneity determination is false, the second transfer unit transfers the control dataset read in the previous predetermined transfer cycle, or dummy data of a predetermined size, to the first transfer unit. The data transfer system according to claim 1.

5. If the result of the data simultaneity determination is true, the second transfer unit performs an ID update determination, which is a determination of whether the sequence ID associated with the control dataset is different between the previous predetermined transfer cycle and the current predetermined transfer cycle. If the result of the ID update determination is true, the second transfer unit transfers the control dataset to the first transfer unit. If the result of the ID update determination is false, the second transfer unit transmits dummy data of a predetermined size to the first transfer unit. The data transfer system according to claim 4.

6. To identify the network characteristics as a relationship between the transfer cycle and delay time of the aforementioned network, the system includes a first test unit and a second test unit that periodically or when a specific network condition is detected, experimentally perform one-way or bidirectional data transfer for each of a plurality of different transfer cycles. The first test unit is provided in the apparatus that is equipped with the first transfer unit, The second test unit is provided in the apparatus that is equipped with the second transfer unit, The first test unit and the second test unit determine the transfer period based on the identified network characteristics, and set the determined transfer period as the predetermined transfer period. The data transfer system according to claim 1.

7. The aforementioned network includes a wireless network. The data transfer system according to claim 1.

8. The control device is a fluid control device. The data transfer system according to claim 1.

9. The predetermined transfer period is the longest transfer period among a plurality of transfer periods belonging to the allowable delay time. The data transfer system according to claim 1.

10. The data transfer system according to claim 1, further comprising the control unit for controlling one or more controlled devices.

11. Factor transfers at predetermined transfer cycles and control transfers at predetermined transfer cycles are performed by the first transfer unit and the second transfer unit. The first memory area and the first transfer unit are provided in at least one of the one or more controlled devices, or in a first data transfer device connected to the one or more controlled devices. The second memory area and the second transfer unit are provided in the control device of the one or more controlled devices, or in the second data transfer device connected to the control device. The first memory area includes a first transmission area and a first reception area. The second memory area includes a second transmission area and a second reception area, The factor dataset is written to the first transmission area. The factor dataset includes factor data for each factor that may influence the control dataset, and for each factor, the factor data includes the values ​​obtained for that factor. The control dataset includes control data for each controlled device, and for each controlled device, the control data includes control parameter values ​​for each of one or more control parameter items. The start of the predetermined transfer period for the factor transfer and the start of the predetermined transfer period for the control transfer are asynchronous. In the factor transfer described above, the first transfer unit reads the factor dataset from the first transmission area, transfers the read factor dataset to the second transfer unit via the network, and the second transfer unit writes the factor dataset to the second reception area. In the control transfer, the second transfer unit reads the control dataset from the second transmission area, transfers the read control dataset to the first transfer unit via the network, and the first transfer unit writes the control dataset to the first reception area. The control device is configured to perform control at a predetermined control cycle, and the control at each predetermined control cycle includes reading a factor dataset from the second receiving area, determining control data for each controlled device based on the read factor dataset, and writing the control dataset containing the determined control data for each controlled device to the second transmitting area. The aforementioned network has a network characteristic in which the delay time differs depending on the transfer cycle. Both the predetermined transfer period for the factor transfer and the predetermined transfer period for the control transfer are transfer periods shorter than the predetermined control period and that fall within the allowable delay time. Data transfer method.

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