Plc system, remote unit, master station, remote unit control method, master station control method, remote unit control program product and master station control program product

Abstract

In each remote unit (300, 400), the operation mode setting unit (301, 401) sets the operation mode based on the user's operation, the connection combination determination unit (302, 402) determines the connection combination between the basic unit and the additional unit based on the set operation mode, and the unit information notification unit (303, 403) notifies the unit information containing the connection combination information. In the master station (100), the IP address assignment unit (122) assigns IP addresses to each remote unit (300, 400) based on the unit information and network structure information obtained by the unit information acquisition unit (121), and the message transmission and reception determination unit (124) determines the form of the information transmitted and received by the master station (100) based on the network structure information updated by the network structure information update unit (123).

Description

Technical Field

[0001] This invention relates to PLC systems, remote units, master stations, remote unit control methods, master station control methods, remote unit control program products, and master station control program products. Background Technology

[0002] In factory production lines, programmable logic controller (PLC) systems are used, consisting of various units, including a central processing unit (CPU) that executes control programs to manage the input and output of instruments. In such a PLC system, if one of the units fails, the faulty unit needs to be quickly replaced to restore the system to normal operation.

[0003] Patent Document 1 discloses a PLC unit system in which multiple units, such as representative units and subordinate units, are connected to a master unit that connects a CPU unit to a network. In Patent Document 1, the multiple units are pre-configured by a PC (Personal Computer) with engineering design tools connected to the CPU unit as virtual units that can be replaced by other faulty units, thereby simplifying the operation of replacing units and reducing operation time.

[0004] Patent Document 1: International Publication No. 2020 / 079730 Summary of the Invention

[0005] In the PLC unit system described in Patent Document 1, if a unit with communication capabilities that allows communication with the main unit via a network fails, it can be replaced by another unit with communication capabilities. However, in a PLC system, for example, additional units are sometimes connected to these units to increase the number of instruments performing input / output control. These additional units, like the CPU unit, do not have communication capabilities. Therefore, the PLC unit system described in Patent Document 1 has the problem that, in the event of a failure of a unit without communication capabilities, such as an additional unit, it is difficult to replace the failed unit with a unit that has communication capabilities.

[0006] The present invention was made in view of the above circumstances, and its purpose is to make it easy to replace a unit without communication function with a unit having communication function.

[0007] To achieve the above objectives, the PLC system of the present invention includes a master station and multiple remote units. The master station includes a CPU unit and a main unit. The multiple remote units are capable of sending and receiving information with the master station via a network. The CPU unit is capable of controlling instruments connected to the remote units. Each remote unit includes: an operation mode setting unit, which sets an operation mode based on user operations to a basic mode or an additional mode. The basic mode is an operation mode in which the unit operates as a basic unit connected to the network and sending and receiving information with the master station. The additional mode is an operation mode in which the unit operates as an additional unit of the basic unit. A connection combination determination unit, which determines the connection combination of the basic unit and the additional unit based on the operation mode set by the operation mode setting unit. A unit information notification unit, which notifies the master station of unit information including connection combination information. This unit information is related to the remote units, and the connection combination information is information that determines the connection combination determined by the connection combination determination unit. The main station includes: a unit information acquisition unit that acquires unit information; an IP address assignment unit that assigns IP addresses to remote units based on the unit information acquired by the unit information acquisition unit and network structure information representing the network structure; a network structure information update unit that updates the network structure information based on the IP addresses assigned by the IP address assignment unit and the unit information acquired by the unit information acquisition unit; and a transmit / receive information decision unit that determines the form of information sent from the main station to the remote units and the form of information received by the main station from the remote units based on the network structure information updated by the network structure information update unit.

[0008] The effects of the invention

[0009] According to the present invention, the remote unit sets its operating mode to either basic mode or extension mode, determines the connection combination of the basic unit and the extension unit, and notifies the master station of unit information containing connection combination information. Then, the master station assigns an IP address to the remote unit based on the obtained unit information, updates the network structure information, and determines the form of information it will send and receive. Thus, in the PLC system of the present invention, as long as the remote unit with communication function is set to extension mode, even if it is replaced by an extension unit without communication function, the master station can still send and receive information with the replaced remote unit in the same way as the original extension unit. As a result, compared with PLC systems where the master station and remote units do not have the above-mentioned functions, the replacement of units without communication function by units with communication function in the PLC system of the present invention becomes easier. Attached Figure Description

[0010] Figure 1 This is a diagram showing the functional structure of the PLC system involved in Implementation Method 1.

[0011] Figure 2This is a block diagram illustrating the hardware structure of the master station and remote unit involved in Implementation Method 1.

[0012] Figure 3 This is an explanatory diagram illustrating the substitution between the added unit and the remote unit involved in Implementation Method 1.

[0013] Figure 4 This is a timing diagram showing the information transmission and reception when the master station in Implementation Method 1 assigns an IP address to a remote unit.

[0014] Figure 5A This is a diagram showing an example of the network structure information before the update involved in Implementation 1.

[0015] Figure 5B This is a diagram showing an example of the updated network structure information according to Implementation Method 1.

[0016] Figure 6 This is a flowchart of the unit information notification processing involved in Implementation Method 1.

[0017] Figure 7 This is a flowchart of the information sending and receiving decision processing involved in Implementation Method 1.

[0018] Figure 8 This is a diagram showing the functional structure of the PLC system involved in Implementation Method 2.

[0019] Figure 9 This is a diagram showing an example of parameter information related to Implementation Method 2.

[0020] Figure 10 This is a flowchart of the parameter information transmission process involved in Implementation Method 2.

[0021] Figure 11A This is a diagram illustrating an example of changes to the network structure information before the update.

[0022] Figure 11B This is a diagram illustrating an example of changes to the updated network structure information.

[0023] Figure 12 This is a diagram showing an example of parameter information changes. Detailed Implementation

[0024] Hereinafter, a PLC system according to embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. Furthermore, the same or equivalent parts in the drawings will be labeled with the same reference numerals.

[0025] [Implementation Method 1]

[0026] (Regarding the PLC system 1 involved in Implementation Method 1)

[0027] The PLC system 1 according to Embodiment 1 of the present invention is, for example, a so-called sequence control system or sequencer system composed of multiple units in a factory production line. These multiple units include a CPU unit 110 (described later) that executes an instrument control program to control the input and output of the instrument. Figure 1 As shown, the PLC system 1 includes a master station 100, a first remote unit 300 and a second remote unit 400, which are examples of remote units. The first remote unit 300 and the second remote unit 400 are connected to the master station 100 via a field network 200, which is an example of a network.

[0028] (Regarding the main station 100 involved in Implementation Method 1)

[0029] The main station 100 includes the aforementioned CPU unit 110 and a main unit 120 connecting the CPU unit 110 to the field network 200. The CPU unit 110 is connected to the engineering design tool 500 (described later) via a USB (Universal Serial Bus) connection. Furthermore, in this embodiment, the connection between the CPU unit 110 and the engineering design tool 500 is a USB (Universal Serial Bus) connection, but it is not limited to this. For example, the connection between the CPU unit 110 and the engineering design tool 500 could also be via an Ethernet connection.

[0030] Here, the engineering design tool 500 is a computer device equipped with an engineering design tool program. The engineering design tool 500 generates, for example, various types of information such as the instrument control program described above, parameter information indicating the parameters used by each unit 110, 120, 300, and 400, and network structure information indicating the structure of the field network 200 (described later), and sends this information to the CPU unit 110. Thus, the CPU unit 110, for example, controls each unit 120, 300, and 400 by using the instrument control program and parameter information received from the engineering design tool 500, thereby enabling control of the input and output of instruments connected to each remote unit 300 and 400.

[0031] The main unit 120 performs information transmission and reception with each remote unit 300 and 400 via the field network 200 based on parameter information received by the CPU unit 110 from the engineering design tool 500 and the network structure information described later. The main unit 120 includes a unit information acquisition unit 121 (described later), an IP address assignment unit 122 (described later) for assigning IP addresses to each remote unit 300 and 400, and a network structure information update unit 123 (described later) for updating the network structure information. Furthermore, the main unit 120 includes a transmission and reception information determination unit 124 for determining the format of information transmitted and received between the main station 100 and each remote unit 300 and 400.

[0032] (Regarding the remote units 300 and 400 involved in Implementation Method 1)

[0033] Each remote unit 300, 400 controls the inputs and outputs relative to the connected instruments. Specifically, each remote unit 300, 400 transmits information received from input instruments (not shown, such as sensors or switches, examples of connected instruments) to the main station 100 via the field network 200. Additionally, each remote unit 300, 400 outputs information received from the main station 100 to output instruments (not shown, such as conductors or drive instruments, examples of connected instruments) via the field network 200. Each remote unit 300, 400 includes an operation mode setting unit 301, 401 (described later) for setting operation modes, a connection combination determining unit 302, 402 for determining the connection combinations between units, and a unit information notification unit 303, 403 (described later) for notifying unit information.

[0034] (Regarding the hardware structure of the main station 100 involved in Implementation Method 1)

[0035] like Figure 2 As shown, the main station 100 has a control unit 51 that executes processing according to control program 59. The control unit 51 has a CPU. The control unit 51 executes processing according to control program 59. Figure 1 The IP address assignment unit 122, the network structure information update unit 123, and the information transmission and reception decision unit 124 shown in the figure are in operation.

[0036] return Figure 2 The main station 100 has a main storage unit 52 that is used as the working area of ​​the control unit 51 for loading the control program 59. The main storage unit 52 has a volatile storage device such as RAM (Random Access Memory).

[0037] In addition, the main station 100 has an external storage unit 53 that pre-stores the control program 59. The external storage unit 53, according to the instructions of the control unit 51, supplies the data stored in the program to the control unit 51 and stores the data supplied from the control unit 51. The external storage unit 53 has a non-volatile storage device such as flash memory, HDD (Hard Disk Drive), or SSD (Solid State Drive).

[0038] In addition, the main station 100 has a transceiver unit 56 for sending and receiving information. The transceiver unit 56 includes information communication components such as a communication network terminal device and a wireless communication device connected to the network. The transceiver unit 56 serves as... Figure 1 The unit information acquisition unit 121 shown in the figure is in operation.

[0039] return Figure 2 In the main station 100, the main storage unit 52, the external storage unit 53 and the transceiver unit 56 are all connected to the control unit 51 via the internal bus 50.

[0040] The main station 100 utilizes the main storage unit 52, external storage unit 53, and transceiver unit 56 as resources through the control unit 51, thereby achieving... Figure 1 The functions of the units 121 to 124 shown above are as follows. For example, the master station 100 performs the unit information acquisition step implemented by the unit information acquisition unit 121 and the IP address assignment step implemented by the IP address assignment unit 122. In addition, for example, the master station 100 performs the network structure information update step implemented by the network structure information update unit 123 and the transmit / receive information decision step implemented by the transmit / receive information decision unit 124.

[0041] (Regarding the hardware structure of each remote unit 300 and 400 involved in Implementation Method 1)

[0042] In addition, each remote unit 300 and 400, like the main station 100, has a control unit 51, a main storage unit 52 connected to the control unit 51 via an internal bus 50, an external storage unit 53, and a transceiver unit 56. The control unit 51 of each remote unit 300 and 400 operates according to the control program 59. Figure 1 The operation mode setting units 301 and 401, and the connection combination determination units 302 and 402 shown are in operation. Additionally, the transceiver units 56 of each remote unit 300 and 400 function as… Figure 1 The unit information notification units 303 and 403 shown are functioning.

[0043] Each remote unit 300 and 400 utilizes the main storage unit 52, external storage unit 53, and transceiver unit 56 as resources through the control unit 51, thereby achieving... Figure 1The functions of the aforementioned units 301-303 and 401-403 are as follows. For example, each remote unit 300 and 400 performs the operation mode setting step implemented by the operation mode setting unit 301 and 401, and the connection combination determination step implemented by the connection combination determination unit 302 and 402. In addition, for example, each remote unit 300 and 400 performs the unit information notification step implemented by the unit information notification unit 303 and 403.

[0044] (Details regarding the functional structure of each remote unit 300, 400 involved in Implementation Method 1)

[0045] return Figure 1 The operation mode setting units 301 and 401 set an operation mode to either the basic mode or the additional mode based on the signal output by the operation mode setting H / W (Hardware) switch (not shown) via user operation. Here, the basic mode refers to the operation mode in which each remote unit 300 and 400 connects to the field network 200 and operates as a basic unit for transmitting and receiving information with the master station 100. The additional mode refers to the operation mode in which an additional unit, acting as a basic unit, operates. Furthermore, the operation mode setting H / W switch is set for each remote unit 300 and 400.

[0046] Here, as Figure 3 As shown, consider a scenario where an additional unit 700 is connected to a third remote unit 600 connected to the master station via a field network 200, and these units 600 and 700 malfunction. Furthermore, the third remote unit 600 is a so-called 32-point remote input unit capable of inputting information received from the master station 100 to 32 instruments connected to it. Additionally, the additional unit 700 is a so-called 16-point remote output unit capable of sending information output from 16 instruments connected to it to the master station 100.

[0047] In this situation, the first remote unit 300 can be replaced by the malfunctioning third remote unit 600 by setting its operating mode to the basic mode. Additionally, in this situation, the second remote unit 400 can be replaced by the malfunctioning extension unit 700 by setting its operating mode to the extension mode.

[0048] Furthermore, in this case, the first remote unit 300 needs to have the same or more connected input and output instruments as the malfunctioning third remote unit 600. That is, the malfunctioning third remote unit 600 needs to be replaced strictly one-to-one by a first remote unit 300 with equivalent or higher functionality. Specifically, the first remote unit 300 needs to be a 32-point remote unit identical to the third remote unit 600.

[0049] On the other hand, in this case, the second remote unit 400 may also have fewer connectable input and output instruments than the faulty expansion unit 700. In this case, the faulty expansion unit 700 may be replaced by multiple remote units, including the second remote unit 400. That is, the faulty expansion unit 700 may be replaced by multiple remote units in a one-to-many manner. For example, the second remote unit 400 is preferably a 16-point remote output unit, just like the expansion unit 700, but it may also be an 8-point remote output unit, and the expansion unit 700 may also be replaced by two 8-point remote output units, including the second remote unit 400.

[0050] Furthermore, although the illustrations are omitted, for example, if one of the multiple addition units 700 connected to the third remote unit 600 malfunctions and needs to be replaced, the second remote unit 400 can also replace it with multiple addition units by setting its operating mode to addition mode. That is, the multiple addition units to be replaced can also be replaced one-to-many by the second remote unit 400, which has equivalent or higher functionality. For example, if the addition unit 700 is two 8-point remote output units, then the two 8-point remote output units can be replaced by a 16-point remote output unit, namely the second remote unit 400.

[0051] return Figure 1 The connection combination determination units 302 and 402 determine the connection combination between the basic unit and the additional unit based on the operation modes of each remote unit 300 and 400 set by the operation mode setting units 301 and 401, and the signal output by the connection combination determination H / W switch (not shown) through user operation. For example, the connection combination determination units 302 and 402 determine to connect the first remote unit 300, which is the basic unit and whose operation mode is set to the basic mode, to the second remote unit 400, which is the additional unit and whose operation mode is set to the additional mode. Furthermore, the connection combination determination H / W switch is also provided in each remote unit 300 and 400 in the same manner as the operation mode setting H / W switch.

[0052] Furthermore, the connection combination determination units 302 and 402 use information that uniquely identifies each remote unit 300 and 400, such as its current IP address, to generate connection combination information that can determine the connection combination. For example, if the current IP address of the first remote unit 300 is "192.168.3.1", the connection combination information of the second remote unit 400, which is an additional unit, includes information that determines the IP address of the basic unit as "192.168.3.1".

[0053] Unit information notification units 303 and 403 notify the master station 100 by sending information related to each remote unit 300 and 400, i.e., unit information. Here, unit information refers to information generated by each remote unit 300 and 400 itself, such as connection combination information of each remote unit 300 and 400 generated by connection combination determination units 302 and 402, information that can determine its own unit category, and information that can determine the number of input and output instruments that can be connected to it.

[0054] (Details regarding the functional structure of the main station 100 involved in Implementation Method 1)

[0055] In addition, the unit information acquisition unit 121 acquires the unit information by receiving the unit information sent from each remote unit 300, 400.

[0056] The IP address assignment unit 122 assigns IP addresses to each remote unit 300 and 400 based on the unit information obtained by the unit information acquisition unit 121 and the network structure information received by the CPU unit 110 from the engineering design tool 500. Furthermore, the network structure information is information categorized according to the units connected to the field network 200, including information representing IP addresses (IP address information), information representing the unit type (unit category information), information setting the type of information transmitted and received by the master station 100 (transmission category setting information), and reception category setting information. For example, ... Figure 5A As shown, network structure information can be displayed in the form of a table.

[0057] like Figure 5A As shown, the network structure information received by the master station 100 from the engineering design tool 500 is, for example, the value of the "No." item representing the identification information of the third remote unit 600 is "1". Furthermore, regarding the network structure information, for example, the value of the "IP address" item representing the IP address information of the third remote unit 600 is "192.168.3.1", and the value of the "unit category" item representing the unit category information of the third remote unit 600 is "mixed input / output". In addition, the value of the "unit category" item is sometimes "input" and "output", except when it is "mixed input / output" in the case of a digital input / output (I / O) unit like the third remote unit 600. Furthermore, the value of the "unit category" item is, for example, "analog input" and "analog output" when the third remote unit 600 is an analog input / output unit.

[0058] Furthermore, regarding network structure information, for example, in the transmission category setting information of the third remote unit 600, the value of the "Device" item is "Input Device," which indicates the type of instrument that inputs information transmitted from the master station 100. Also, regarding network structure information, for example, in the transmission category setting information of the third remote unit 600, the value of the "Number of Points" item is "32 points," the value of the "Start" item is "00," and the value of the "End" item is "1F." The "Number of Points" item indicates the number of instruments that input information transmitted from the master station 100, the "Start" item indicates the starting address of the instrument, and the "End" item indicates the ending address of the instrument.

[0059] Furthermore, regarding network structure information, for example, in the reception category setting information of the third remote unit 600, the value of the "Device" item is "Output Device," which indicates the type of instrument that outputs information received by the master station 100. Also, regarding network structure information, for example, in the reception category setting information of the third remote unit 600, the value of the "Number of Points" item is "16 points," the value of the "Start" item is "00," and the value of the "End" item is "0F." The "Number of Points" item indicates the number of instruments that output information received by the master station 100, the "Start" item indicates the starting address of the instrument, and the "End" item indicates the ending address of the instrument.

[0060] return Figure 1 The IP address assignment unit 122 can, for example, assign the IP address of the third remote unit 600 to the first remote unit 300 that is being replaced by the third remote unit 600.

[0061] Here, the master station 100 cannot send or receive information with remote units whose IP addresses are not present in the network structure information. Therefore, the master station 100 needs to determine the IP address of the remote unit whose operation mode is set to add mode. On the other hand, if the remote address determines its own IP address, it may be duplicated with the IP address of a remote unit already present in the network structure information. In this case, the master station 100 cannot send or receive information with remote units whose operation mode is set to add mode. For example, if the IP address of the second remote unit 400, whose operation mode is set to add mode, is duplicated with the IP address of another remote unit present in the network structure information, the master station 100 cannot send or receive information with the second remote unit 400.

[0062] Therefore, the IP address assignment unit 122 determines unused IP addresses that are not present in the network structure information and dynamically assigns IP addresses to remote units whose operation mode is set to add mode. Specifically, the IP address assignment unit 122 assigns an IP address to the second remote unit 400 using DHCP (Dynamic Host Configuration Protocol). That is, the master station 100 assigns an IP address to the second remote unit 400 by having the IP address assignment unit 122 act as a DHCP server.

[0063] For example, such as Figure 4 As shown, firstly, when the operation mode of the second remote unit 400 is set to the addition mode, it determines the master station 100 by... Figure 2 The transceiver unit 56 shown sends a DHCP Discover data packet to all units in the field network 200. Next, upon receiving the DHCP Discover data packet at the transceiver unit 56 of the master station 100, the IP address assignment unit 122 determines an unused IP address from its stored network structure information. Then, the IP address assignment unit 122 sends a DHCP Offer data packet, indicating the determined IP address, to the second remote unit 400 via the transceiver unit 56. In this manner, the IP address assignment unit 122 proposes an IP address to the second remote unit 400; specifically, it proposes an unused IP address, "192.168.3.2".

[0064] Next, upon receiving a DHCP Offer packet, the second remote unit 400 sends a DHCP Request packet to the master station 100, indicating a request for the allocation of the IP address proposed by the transceiver unit 56. Then, upon receiving the DHCP Request packet from the transceiver unit 56 of the master station 100, the IP address assigning unit 122 sends a DHCP Acknowledge packet indicating permission for allocation by the transceiver unit 56 to the second remote unit 400. The proposed IP address is then applied in the second remote unit 400 in the manner described above.

[0065] return Figure 1The network structure information updating unit 123 updates the network structure information based on the IP address assigned by the IP address assignment unit 122 and the unit information obtained by the unit information acquisition unit 121. After the IP address assignment unit 122 applies the IP address to the second remote unit 400, the network structure information updating unit 123 updates the network structure information based on the IP address of each remote unit 300, 400, the connection combination information of each remote unit 300, 400 included in the unit information, the information that can determine the category of each remote unit 300, 400, and the information that can determine the number of input instruments and output instruments that can be connected to each remote unit 300, 400.

[0066] For example, such as Figure 5B As shown, regarding the updated network structure information, for example, the value of the "No." item, indicating that the first remote unit 300, which was replaced by the third remote unit 600, is "1", and the value of the "No." item, indicating that the second remote unit 400, which was replaced by the added unit 700, is "2". Furthermore, regarding the updated network structure information, for example, the value of the "IP address" item, indicating the IP address information of the first remote unit 300, is "192.168.3.1", and the value of the "IP address" item, indicating the IP address information of the second remote unit 400, is "192.168.3.2".

[0067] Furthermore, regarding the updated network structure information, for example, the value of the "Unit Category" item in the unit category information of the first remote unit 300 is "Input," and the value of the "Unit Category" item in the unit category information of the second remote unit 400 is "Output." Additionally, regarding the updated network structure information, for example, in the transmission category setting information of the first remote unit 300, the value of the "Device" item is "Input Device," the value of the "Number of Points" item is "32 Points," the value of the "Start" item is "00," and the value of the "End" item is "1F." The "Start" item indicates the starting address of the instrument, and the "End" item indicates the ending address of the instrument. Therefore, the transmission category setting information of the first remote unit 300 in the updated network structure information remains unchanged compared to the transmission category setting information of the third remote unit 600 in the previous network structure information.

[0068] Furthermore, regarding the updated network structure information, for example, in the receiver category setting information of the second remote unit 400, the value of the "Device" item is "Output Device," the value of the "Number of Points" item is "16 Points," the value of the "Start" item is "00," and the value of the "End" item is "0F." The "Start" item indicates the starting address of the instrument, and the "End" item indicates the ending address of the instrument. Therefore, the receiver category setting information of the second remote unit 400 in the updated network structure information remains unchanged compared to the receiver category setting information of the third remote unit 600 in the previous network structure information.

[0069] return Figure 1 The transceiver information decision unit 124 determines the format of information sent from the master station 100 to each remote unit 300, 400 and the format of information received by the master station 100 from each remote unit 300, 400 based on the network structure information updated by the network structure information update unit 123. As a result, the master station 100 transmits and receives information with each remote unit 300, 400 based on the updated network structure information and the format of information determined by the transceiver information decision unit 124, thereby enabling information input and output relative to instruments connected to each remote unit 300, 400.

[0070] (Regarding the unit information notification processing involved in Implementation Method 1)

[0071] Next, a flowchart will be used to illustrate the action of notifying the main station 100 of unit information when each remote unit 300, 400 is replaced by the third remote unit 600 and the additional unit 700. For example, if power is turned on after being replaced by the third remote unit 600 and the additional unit 700, each remote unit 300, 400 will begin execution. Figure 6 The unit information notification processing is shown.

[0072] First, such as Figure 6 As shown, the operation mode setting units 301 and 401 set an operation mode to either the basic mode or the additional mode based on the signal from the H / W switch (step S101). For example, based on the signal from the H / W switch, the operation mode setting unit 301 of the first remote unit 300 sets the operation mode to the basic mode, and the operation mode setting unit 401 of the second remote unit 400 sets the operation mode to the additional mode.

[0073] After setting the operating mode, the connection combination determination units 302 and 402 determine the connection combination of the basic unit and the additional unit based on the set operating mode of each remote unit 300 and 400, and generate connection combination information (step S102). For example, based on the signal from the H / W switch, the connection combination determination units 302 and 402 determine to connect the first remote unit 300 whose operating mode is set to the basic mode and the second remote unit 400 whose operating mode is set to the additional mode, and generate connection combination information.

[0074] After generating the connection combination information, the unit information notification units 303 and 403 notify the master station 100 of the unit information by sending the unit information of each remote unit 300 and 400 containing the generated connection combination information (step S103), and then end the process. For example, the unit information notification units 303 and 403 send the unit information containing the following information to the master station 100 and end the process: the connection combination information generated by each remote unit 300 and 400 itself, information that can determine the unit category, and information that can determine the number of instruments that can be connected.

[0075] (Regarding the information sending and receiving decision processing involved in Implementation Method 1)

[0076] Next, a flowchart will be used to illustrate the actions taken by the master station 100 in determining the form of information to be sent and received with the replaced remote units 300 and 400. For example, if power is turned on after the remote units 300 and 400 have been replaced, the master station 100 will begin executing... Figure 7 The sent and received information shown determines how to process it.

[0077] First, such as Figure 7 As shown, the unit information acquisition unit 121 acquires the unit information by receiving it from each remote unit 300 and 400 (step S201). The IP address assignment unit 122 assigns an IP address to each remote unit 300 and 400 based on the acquired unit information and the network structure information stored therein (step S202). For example, the IP address assignment unit 122 assigns the IP address of the replaced third remote unit 600, i.e., "192.168.3.1", to the first remote unit 300, and uses the IP address of the second remote unit 400... Figure 4 The DHCP server shows that it assigns an unused IP address, "192.168.3.2".

[0078] After assigning an IP address, the network structure information updating unit 123 updates the network structure information based on the assigned IP address and the obtained unit information (step S203). For example, the network structure information updating unit 123 obtains the IP address from the network structure information. Figure 5A The network structure information shown before the update has been updated to: Figure 5BThe updated network structure information is shown. After updating the network structure information, the transceiver information decision unit 124 determines the form of information sent from the master station 100 to each remote unit 300, 400 and the form of information received by the master station 100 from each remote unit 300, 400 based on the updated network structure information (step S204), and ends the processing.

[0079] As explained above, according to the PLC system 1 of this embodiment, the master station 100 includes a CPU unit 110 and a master unit 120. The master unit 120 is capable of transmitting and receiving information relative to each remote unit 300, 400, and 600 connected to the field network 200. Therefore, the CPU unit 110 is capable of controlling the instruments connected to each remote unit 300, 400, and 600.

[0080] Furthermore, each remote unit 300 and 400 can be interchanged with the third remote unit 600 and the additional unit 700. In this case, in each remote unit 300 and 400, the operation mode setting units 301 and 401 set an operation mode between the basic mode and the additional mode based on the user's operation, and the connection combination determination units 302 and 402 determine the connection combination between the basic unit and the additional unit based on the set operation mode. Moreover, in each remote unit 300 and 400, the unit information notification units 303 and 403 notify the main station 100 of the unit information including the connection combination information.

[0081] Furthermore, in the master station 100, the unit information acquisition unit 121 acquires unit information, and the IP address assignment unit 122 assigns IP addresses to each remote unit 300 and 400 based on the acquired unit information and the network structure information stored therein. Additionally, in the master station 100, the network structure information update unit 123 updates the network structure information based on the assigned IP addresses and the acquired unit information. Moreover, in the master station 100, the transmit / receive information determination unit 124 determines the format of information sent from the master station 100 to each remote unit 300 and 400 and the format of information received by the master station 100 from each remote unit 300 and 400 based on the updated network structure information.

[0082] In the manner described above, as long as the second remote unit 400 with communication function is set to the addition mode, even if it is replaced by the addition unit 700 without communication function, the master station 100 can still perform information transmission and reception with the second remote unit 400 after the replacement, just like the addition unit 700 before the replacement. As a result, for the PLC system 1 according to this embodiment, compared with a PLC system where the master station and remote units do not have the above-mentioned functions, it becomes easier to replace the unit without communication function with the unit with communication function.

[0083] In conventional PLC systems like Patent Document 1, when an add-on unit malfunctions and needs replacement, it is typically replaced with a unit identical to the malfunctioning add-on unit. However, if the user does not have a spare part for the identical add-on unit, even if they want to order it, the delivery time is sometimes long or orders cannot be placed due to production stoppages, making it difficult to quickly obtain the same add-on unit. In such cases, in order to quickly replace the malfunctioning add-on unit and restore the system, the user sometimes replaces it with a basic unit.

[0084] In this scenario, the user needs to update various information such as control programs, parameter information, and network structure information using an engineering design tool after the replacement. This engineering design tool is then connected to the CPU unit to send the updated information. Therefore, in conventional PLC systems, when replacing a basic unit with a non-communication-functional addition unit with a basic unit that already has communication capabilities, a user skilled in using engineering design tools to update this information is required to perform the task. Furthermore, even for such users in conventional PLC systems, the replacement process is time-consuming, resulting in a heavy workload for them.

[0085] Furthermore, in previous PLC systems, depending on the location where the PLC system was installed, for example, sometimes for security reasons, engineering design tools were prohibited from being carried and could not be connected to the CPU unit. In such cases, there was a problem that the system could not be quickly restored.

[0086] In contrast, in the PLC system 1 of this embodiment, each remote unit 300, 400 uses signals from its own H / W switch to set its operating mode, determine the connection combination, and notify the master station of the unit information. Furthermore, the master station uses the acquired unit information and its own stored information to assign IP addresses to each remote unit 300, 400, update the network structure information, and determine the format for sending and receiving information.

[0087] Therefore, in the PLC system 1 according to this embodiment, even if the user does not use the engineering design tool 500 to update the information, but connects the engineering design tool 500 to the CPU unit 110 and sends the updated information to the CPU unit 110, the user can still perform information transmission and reception relative to the second remote unit 400, which has replaced the addition unit 700. As a result, compared with conventional PLC systems, the replacement of the addition unit 700 without communication function by the second remote unit 400 with communication function in the PLC system 1 according to this embodiment becomes easier, and the user can quickly restore the PLC system 1.

[0088] [Implementation Method 2]

[0089] In Embodiment 1, the operation mode setting units 301 and 401 set the operation mode based on signals from the H / W switch, and the connection combination determination units 302 and 402 determine the connection combination based on signals from the H / W switch, but are not limited thereto. For example, the setting of the operation mode and the determination of the connection combination can also be performed using parameter information generated by the master station. Hereinafter, refer to Figures 8-10 The PLC system 1 according to Embodiment 2 will be described in detail. In addition, in Embodiment 2, the structure that is different from that in Embodiment 1 will be described, and the structure that is the same as that in Embodiment 1 will be omitted from the description due to its length.

[0090] (Regarding the main station 100 involved in implementation method 2)

[0091] like Figure 8 As shown, in the PLC system 1 of this embodiment, the master station 100 is supplemented with a unit replacement determination unit 125 for determining whether the replacement of remote units with each other is feasible, a parameter information generation unit 126 for generating parameter information, and a parameter information sending unit 127 for sending parameter information.

[0092] (Regarding the remote units 300 and 400 involved in Implementation Method 2)

[0093] Furthermore, in the PLC system 1 according to this embodiment, a parameter information receiving unit 304, 404 for receiving parameter information is added to each remote unit 300, 400. In addition, in this embodiment, the H / W switch for setting the operating mode and the H / W switch for determining the connection combination are omitted from each remote unit 300, 400.

[0094] (Regarding the hardware structure of the main station 100 involved in Implementation Method 2)

[0095] like Figure 2 As shown, the control unit 51 of the main station 100, according to the control procedure 59, acts as... Figure 8 The unit replacement determination unit 125 and parameter information generation unit 126 shown in the diagram are functioning. Additionally, the transceiver unit 56 of the main station 100 functions as... Figure 8 The parameter information transmission unit 127 shown is operational. The master station 100 utilizes the main storage unit 52, external storage unit 53, and transceiver unit 56 as resources through the control unit 51, thereby achieving... Figure 8 The functions of the aforementioned parts 121 to 127 are as follows. For example, the main station 100 executes the unit replacement determination step implemented by the unit replacement determination unit 125, the parameter information generation step implemented by the parameter information generation unit 126, and the parameter information transmission step implemented by the parameter information transmission unit 127.

[0096] (Regarding the hardware structure of each remote unit 300 and 400 involved in Implementation Method 2)

[0097] In addition, the transceiver unit 56 of each remote unit 300 and 400 serves as Figure 8 The parameter information receiving units 304 and 404 shown are operational. Each remote unit 300 and 400 utilizes the main storage unit 52, external storage unit 53, and transceiver unit 56 as resources through the control unit 51, thereby achieving... Figure 8 The functions of the aforementioned units 301-304 and 401-404 are as follows. For example, each remote unit 300 and 400 performs the parameter information receiving step implemented by the parameter information receiving units 304 and 404.

[0098] (Details regarding the functional structure of the main station 100 involved in Implementation Method 2)

[0099] The unit replacement determination unit 125 determines whether it is possible to replace other remote units and additional units 700 by each remote unit 300, 400 based on the unit information obtained by the unit information acquisition unit 121 and the network structure information updated by the network structure information update unit 123. The unit replacement determination unit 125 compares the unit category and the number of connectable instruments contained in the unit information with the unit category information, transmission category setting information and reception category setting information of the updated network structure information, and determines whether there are any abnormalities in the combination of unit categories and the number of connectable instruments.

[0100] For example, if the cell replacement determination unit 125 determines that a cell cannot be replaced if the updated network structure information shows a cell category that is either a mixed input / output cell or includes both input and output, but the cell information shows a cell category that is only an output cell. Additionally, for example, if the updated network structure information shows a total of 64 connectable instruments, but the cell information shows a total of 32 connectable instruments, the cell replacement determination unit 125 determines that a cell cannot be replaced. In this case, the master station 100 can also output an indication that an error has occurred in the field network 200.

[0101] When the third remote unit 600 is replaced by each of the remote units 300 and 400, and the additional unit 700 is added, the parameter information generation unit 126 generates parameter information based on the acquired unit information and the updated network structure information. In this embodiment, the master station 100 receives in advance the parameter information of each of the remote units 300, 400, and 600 generated by the user using the engineering design tool 500. Therefore, the parameter information generation unit 126 updates its stored parameter information based on the unit information and the updated network structure information, thereby generating new parameter information.

[0102] Here, in this embodiment, the parameter information includes information that determines whether the operating mode of each remote unit 300, 400 is a basic mode or an additional mode; and information that determines the connection combination of the remote units 300, 400. Additionally, as... Figure 9 As shown, the parameter information includes information representing common unit parameters independent of unit type, namely unit common parameter information, and information representing input / output parameters dependent on unit type, namely input / output parameter information. Additionally, the input / output parameter information includes information representing input parameters, namely input parameter information, and information representing output parameters, namely output parameter information. Furthermore, the input parameter information and output parameter information represent parameters set for each instrument connected to the input / output.

[0103] Therefore, since the unit category of the third remote unit 600 is "input-output hybrid", the parameter information of the third remote unit 600, which is connected to the addition unit 700, includes unit common parameter information and input-output parameter information, and the input-output parameter information includes the output parameter information of the addition unit 700. Therefore, when the third remote unit 600 receives the parameter information, the addition unit 700 can operate by referring to the unit common parameter information and its own output parameter information shown in the parameter information.

[0104] Furthermore, since the unit category of the first remote unit 300 is "input", the parameter information of the first remote unit 300, which replaces the third remote unit 600, includes unit common parameter information and input parameter information. On the other hand, since the unit category of the second remote unit 400 is "output", the parameter information of the second remote unit 400, which replaces the additional unit 700, includes unit common parameter information and output parameter information.

[0105] The parameter information sending unit 127 sends the parameter information generated by the parameter information generation unit 126 to each remote unit 300, 400. Furthermore, in this embodiment, when a user replaces a remote unit, the engineering design tool 500 sends information indicating that the remote units 300, 400 have scheduled the transmission of parameter information to the CPU unit 110. Therefore, when the power is turned on and the field network 200 is initially set up after the replacement, the parameter information sending unit 127 sends the parameter information to each remote unit 300, 400 as shown in the information received by the CPU unit 110.

[0106] Furthermore, in this embodiment, when the network structure information updating unit 123 updates the network structure information, it also updates the information regarding the transmission reservation of the parameter information based on the updated network structure information. At this time, as... Figure 9As shown, the network structure information update unit 123 updates the common parameter information of the units by sending this common parameter information to all the replaced remote units 300 and 400. On the other hand, the network structure information update unit 123 performs the following update: for the input parameter information in the input-output parameter information, the input parameter information is sent only to the first remote unit 300, and for the output parameter information in the input-output parameter information, the output parameter information is sent only to the second remote unit 400.

[0107] (Details regarding the functional structure of each remote unit 300, 400 involved in Implementation Method 2)

[0108] The parameter information receiving units 304 and 404 receive the parameter information from each remote unit 300 and 400 sent from the main station 100.

[0109] Based on the parameter information received by the parameter information receiving units 304 and 404, the operation mode setting units 301 and 401 set the operation mode to a certain operation mode between the basic mode and the additional mode. Specifically, the operation mode setting units 301 and 401 determine whether the operation mode of each remote unit 300 and 400 is the basic mode or the additional mode based on the parameter information, and then set the operation mode.

[0110] The connection combination determination units 302 and 402 determine the connection combination between the basic unit and the additional unit based on the operation modes of each remote unit 300 and 400 set by the operation mode setting units 301 and 401 and the parameter information received by the parameter information receiving units 304 and 404. Specifically, the connection combination determination units 302 and 402 determine the connection combination between the basic unit and the additional unit by determining the connection combination of the remote units 300 and 400 according to the parameter information.

[0111] (Regarding the parameter information transmission processing involved in Implementation Method 2)

[0112] Next, a flowchart will be used to illustrate the actions of sending the parameter information generated by the master station 100 to each remote unit 300, 400, and 600. For example, the master station 100 begins execution when the power is turned on. Figure 10 The parameter information shown is sent and processed.

[0113] First, such as Figure 10 As shown, the parameter information sending unit 127 sends the parameter information generated by the user using the engineering design tool 500 to each remote unit 300, 400 based on the information indicating the sending reservation of parameter information obtained from the engineering design tool 500 (step S301).

[0114] After sending the parameter information, the master station 100 determines whether the network structure information updating unit 123 has updated the information indicating the transmission reservation of the parameter information by updating the network structure information (step S302). If the information indicating the transmission reservation of the parameter information has not been updated (step S302; N), the master station 100 repeatedly executes step S302 until the information indicating the transmission reservation of the parameter information is updated. On the other hand, if the information indicating the transmission reservation of the parameter information has been updated (step S302; Y), the parameter information generation unit 126 updates the parameter information based on the acquired unit information and the updated network structure information (step S303). After updating the parameter information, the parameter information sending unit 127 sends the updated parameter information to each remote unit 300, 400 (step S304), and the process ends.

[0115] Furthermore, regarding the action of the main station 100 in determining whether the replacement of remote units is feasible, the unit replacement determination unit 125 only determines the feasibility of the replacement of remote units based on the unit information and the updated network structure information. Therefore, to reduce lengthy explanations, illustrations and detailed descriptions are omitted.

[0116] As explained above, in the PLC system 1 according to this embodiment, the unit replacement determination unit 125 in the master station 100 can determine whether the replacement of remote units with each other is feasible based on the acquired unit information and the updated network structure information.

[0117] In the manner described above, the PLC system 1 of this embodiment can detect anomalies in the updated network structure after the network structure information has been updated by replacing remote units with each other.

[0118] Furthermore, according to the PLC system 1 of this embodiment, in the master station 100, the parameter information generation unit 126 generates parameter information used by each of the replaced remote units 300 and 400 based on the acquired unit information and the updated network structure information when the remote units are replaced. In addition, in the master station 100, the parameter information sending unit 127 sends the generated parameter information, and in each of the remote units 300 and 400, the parameter information receiving units 304 and 404 receive the parameter information.

[0119] In the manner described above, in the PLC system 1 of this embodiment, the master station 100 can automatically generate and send the parameter information used by each of the replaced remote units 300 and 400, and update the parameter information of each of the replaced remote units 300 and 400.

[0120] Furthermore, according to the PLC system 1 of this embodiment, in the master station 100, the parameter information sending unit 127 sends parameter information generated and sent by the user using the engineering design tool 500. Additionally, in each remote unit 300 and 400, the parameter information receiving units 304 and 404 receive parameter information sent from the master station 100. Moreover, in each remote unit 300 and 400, the operation mode setting units 301 and 401 use the received parameter information to set the operation mode, and the connection combination determination units 302 and 402 use the received parameter information to determine the connection combination between the basic unit and the additional unit.

[0121] In this manner, each remote unit 300 and 400 can use parameter information generated by the user using the engineering design tool 500 to set the operating mode or determine the connection combination. As a result, even without using the H / W switches set in each remote unit 300 and 400, each remote unit 300 and 400 can still set the operating mode or determine the connection combination.

[0122] [Example of Change]

[0123] Furthermore, in embodiments 1 and 2 described above, one additional unit 700 is replaced by one second remote unit 400, which can be used as a basic unit. However, multiple additional units can also be replaced by multiple remote units. For example, such as Figure 12 As shown, when the third remote unit 600 is connected to the addition unit 700 and the new addition unit 710, the new addition unit 710 can be replaced by the fourth remote unit 800.

[0124] In this case, for example, if the newly added unit 710 is a so-called 16-point remote input unit, then as a whole, the third remote unit 600 is a remote input / output unit with 48 input points and 16 output points. Therefore, for example, Figure 11A The network structure information shown before the update has the following values: "Points" for the "Send Class" information is "48 points," and "End" is "2F." Additionally, for example, regarding... Figure 11B Regarding the updated network structure information shown, the value of the "No." item, which indicates that the fourth remote unit 800, which has been replaced by the newly added unit 710, is "2", and the value of the "No." item, which indicates that the second remote unit 400, which has been replaced by the added unit 700, is "3".

[0125] Furthermore, for example, regarding the updated network structure information, the IP address information of the fourth remote unit 800, i.e., the value of the "IP address" field, is "192.168.3.2," and the IP address information of the second remote unit 400, i.e., the value of the "IP address" field, is "192.168.3.3." Additionally, for example, regarding the updated network structure information, the unit category information of the fourth remote unit 800, i.e., the value of the "unit category" field, is "input," the value of the "device" field in the transmission category setting information of the fourth remote unit 800 is "input device," the value of the "number of points" field is "16 points," the value of the "start" field is "1F," and the value of the "end" field, indicating the end address of the instrument, is "2F."

[0126] In addition, in this case, such as Figure 12 As shown, the network structure information update unit 123 updates the common parameter information of the units by sending this information to all the replaced remote units 300, 400, and 800. On the other hand, the network structure information update unit 123 also updates the input parameter information in the input / output parameter information by sending related information to the first remote unit 300 and the fourth remote unit 800, and by sending the output parameter information only to the second remote unit 400.

[0127] Furthermore, in Embodiment 2 described above, the unit substitution determination unit 125 determines whether the substitution of remote units with each other is feasible based on unit information and updated network structure information, but is not limited to this. For example, the unit substitution determination unit 125 may also determine whether the substitution of remote units with each other is feasible based on unit information and network structure information before the update. In this case, the master station 100 may also output that an error occurred in the field network 200 and the network structure information could not be updated.

[0128] Furthermore, the central part that serves as the processing center for the master station 100 and each remote unit 300, 400, which includes a control unit 51, a main storage unit 52, an external storage unit 53, an operation unit 54, a transceiver unit 56, and an internal bus 50, can, for example, store the program for performing the aforementioned actions on a recording medium, such as flash memory, readable by the master station 100 and each remote unit 300, 400, and distribute it. By installing this program, the master station 100 and each remote unit 300, 400 are configured to perform the aforementioned processing. Alternatively, the program can be pre-stored in the storage device of a server device on a communication network such as a LAN or the Internet, and downloaded by the master station 100 and each remote unit 300, 400, thereby configuring the master station 100 and each remote unit 300, 400.

[0129] In addition, if the functions of the main station 100 and each remote unit 300 and 400 are achieved through the sharing of OS (Operating System) and application, or through the collaborative action between OS and application, then only the application part may be stored on the recording medium or storage device.

[0130] Alternatively, the program can be overlaid on a carrier wave and provided via a communication network. For example, the program can be announced on a bulletin board system (BBS) on the communication network and provided via the network. Furthermore, the program can be launched and executed under the control of the OS, just like other applications, to perform the aforementioned processing.

[0131] This invention allows for various embodiments and modifications without departing from its broad spirit and scope. Furthermore, the above embodiments are illustrative and not intended to limit the scope of the invention. That is, the scope of the invention is defined by the claims, not the embodiments. Moreover, various modifications implemented within the scope of the claims and their equivalents are considered to be included within the scope of this invention.

[0132] Explanation of the label

[0133] 1…PLC system, 50…Internal bus, 51…Control unit, 52…Main storage unit, 53…External storage unit, 56…Transmit / receive unit, 59…Control program, 100…Master station, 110…CPU unit, 120…Main unit, 121…Unit information acquisition unit, 122…IP address assignment unit, 123…Network structure information update unit, 124…Transmit / receive information decision unit, 125…Unit replacement determination unit, 126…Parameter information generation unit, 12… 7…Parameter information transmission unit, 200…Field network, 300…First remote unit, 301, 401…Action mode setting unit, 302, 402…Connection combination determination unit, 303, 403…Unit information notification unit, 304, 404…Parameter information receiving unit, 400…Second remote unit, 500…Engineering design tool, 600…Third remote unit, 700…Additional unit, 710…Additional unit, 800…Fourth remote unit.

Claims

1. A PLC system comprising a master station and multiple remote units, the master station comprising a CPU unit and a main unit, the multiple remote units being capable of transmitting and receiving information with the master station via a network, and the CPU unit being capable of controlling instruments connected to the remote units. in, The remote unit includes: The action mode setting unit sets an action mode between a basic mode and an additional mode based on the operation performed by the user. The basic mode is an action mode that operates as a basic unit for sending and receiving information with the master station when connected to the network, and the additional mode is an action mode that operates as an additional unit of the basic unit. The connection combination determination unit determines the connection combination of the basic unit and the additional unit based on the operation mode set by the operation mode setting unit. as well as The unit information notification unit notifies the master station of unit information containing connection combination information. This unit information is related to the remote unit, and the connection combination information is information that can determine the connection combination determined by the connection combination determination unit. The main site includes: A unit information acquisition unit acquires the unit information; The IP address assignment unit assigns an IP address to the remote unit based on the unit information obtained by the unit information acquisition unit and information representing the structure of the network, namely network structure information; The network structure information updating unit updates the network structure information based on the IP address assigned by the IP address assignment unit and the unit information obtained by the unit information acquisition unit. as well as The information transmission and reception decision unit determines the form of information sent from the master station to the remote unit and the form of information received by the master station from the remote unit based on the network structure information updated by the network structure information update unit.

2. The PLC system according to claim 1, wherein, The main station also includes a unit replacement determination unit, which determines whether the replacement of the remote units with each other is feasible based on the unit information obtained by the unit information acquisition unit and the network structure information updated by the network structure information update unit.

3. The PLC system according to claim 1 or 2, wherein, The main site also includes: The parameter information generation unit, when the remote unit is replaced, generates information representing the parameters used by the replaced remote unit, i.e., parameter information, based on the unit information obtained by the unit information acquisition unit and the network structure information updated by the network structure information update unit. as well as The parameter information sending unit sends the parameter information generated by the parameter information generating unit. The remote unit also includes a parameter information receiving unit for receiving the parameter information.

4. A remote unit capable of transmitting and receiving information via a network with a master station of a PLC system comprising a CPU unit and a main unit, wherein the CPU unit can control instruments connected to the remote unit. in, This remote unit contains: The action mode setting unit sets an action mode between a basic mode and an additional mode based on the operation performed by the user. The basic mode is an action mode that operates as a basic unit for sending and receiving information with the master station when connected to the network, and the additional mode is an action mode that operates as an additional unit of the basic unit. A connection combination determination unit determines the connection combination of the basic unit and the additional unit based on the operation mode set by the operation mode setting unit; and The unit information notification unit notifies the master station of unit information containing connection combination information and related to the remote unit. This connection combination information is information that can determine the connection combination determined by the connection combination determination unit. The application uses an IP address assigned by the master station based on the unit information and information representing the structure of the network, i.e., network structure information, and sends and receives information with the master station in a form determined by the master station based on the network structure information updated by the master station according to the IP address and the unit information.

5. A master station, which is the master station of a PLC system, the master station comprising a CPU unit and a main unit, the master station being capable of controlling instruments connected to multiple remote units that can transmit and receive information via a network. in, This main site includes: The unit information acquisition unit acquires unit information from the remote unit. This unit information is information that includes connection combination information and is related to the remote unit. The connection combination information is information that can determine the connection combination between the basic unit and the additional units of the basic unit. The basic unit refers to the basic unit that the remote unit connects to the network determined to perform information transmission and reception with the master station. The IP address assignment unit assigns an IP address to the remote unit based on the unit information obtained by the unit information acquisition unit and information representing the structure of the network, namely network structure information; The network structure information updating unit updates the network structure information based on the IP address assigned by the IP address assignment unit and the unit information obtained by the unit information acquisition unit. as well as The information transmission and reception decision unit determines the form of information sent from the master station to the remote unit and the form of information received by the master station from the remote unit based on the network structure information updated by the network structure information update unit.

6. A remote unit control method, which is a method for controlling a remote unit, wherein the remote unit can transmit and receive information with the master station of a PLC system including a CPU unit and a main unit via a network, and the CPU unit can control instruments connected to the remote unit. in, The remote unit control method includes the following steps: The action mode setting step involves setting the remote unit to a certain action mode between a basic mode and an additional mode based on the operation performed by the user. The basic mode is an action mode in which the remote unit acts as a basic unit that connects to the network and sends and receives information with the master station. The additional mode is an action mode in which the remote unit acts as an additional unit of the basic unit. In the connection combination determination step, the remote unit determines the connection combination of the basic unit and the additional unit based on the action mode set in the action mode setting step; and In the unit information notification step, the remote unit notifies the master station of unit information containing connection combination information and related to the remote unit. This connection combination information is information that can determine the connection combination determined in the connection combination decision step. The remote unit application uses an IP address assigned by the master station based on the unit information and information representing the structure of the network, i.e., network structure information, and sends and receives information with the master station in a form determined by the master station based on the network structure information updated by the master station according to the IP address and the unit information.

7. A master station control method for controlling a master station of a PLC system, the master station comprising a CPU unit and a main unit, the master station being capable of controlling instruments connected to multiple remote units that can transmit and receive information via a network. in, The master station control method includes the following steps: The unit information acquisition step involves obtaining unit information from the remote unit. This unit information includes connection combination information and is related to the remote unit. The connection combination information is information that can determine the connection combination between the basic unit and the additional units of the basic unit. The basic unit refers to the basic unit that the remote unit connects with the determined network to conduct information transmission and reception with the master station. In the IP address assignment step, the master station assigns an IP address to the remote unit based on the unit information obtained in the unit information acquisition step and the information representing the structure of the network, namely the network structure information. In the network structure information update step, the main station updates the network structure information based on the IP address assigned in the IP address assignment step and the unit information obtained in the unit information acquisition step. as well as In the information sending and receiving decision step, the master station determines the form of the information sent from the master station to the remote unit and the form of the information received from the remote unit by the master station based on the network structure information updated in the network structure information update step.

8. A remote unit control program product, which is a program product for controlling a remote unit, the remote unit being able to send and receive information with the master station of a PLC system including a CPU unit and a main unit via a network, and the CPU unit being able to control instruments connected to the remote unit. in, The remote unit control program product enables the remote unit to function as the following component: The action mode setting unit sets an action mode between a basic mode and an additional mode based on the operation performed by the user. The basic mode is an action mode that operates as a basic unit for sending and receiving information with the master station when connected to the network, and the additional mode is an action mode that operates as an additional unit of the basic unit. A connection combination determination unit determines the connection combination of the basic unit and the additional unit based on the operation mode set by the operation mode setting unit; and The unit information notification unit notifies the master station of unit information containing connection combination information and related to the remote unit. This connection combination information is information that can determine the connection combination determined by the connection combination determination unit. The remote unit application uses an IP address assigned by the master station based on the unit information and information representing the structure of the network, i.e., network structure information, and sends and receives information with the master station in a form determined by the master station based on the network structure information updated by the master station according to the IP address and the unit information.

9. A master station control program product, which is a program product for controlling a master station of a PLC system, the master station including a CPU unit and a main unit, the master station being capable of controlling instruments connected to multiple remote units that can transmit and receive information via a network. in, The master station control program product enables the master station to function as the following components: The unit information acquisition unit acquires unit information from the remote unit. This unit information is information that includes connection combination information and is related to the remote unit. The connection combination information is information that can determine the connection combination between the basic unit and the additional units of the basic unit. The basic unit refers to the basic unit that the remote unit connects to the network determined to perform information transmission and reception with the master station. The IP address assignment unit assigns an IP address to the remote unit based on the unit information obtained by the unit information acquisition unit and information representing the structure of the network, namely network structure information; The network structure information updating unit updates the network structure information based on the IP address assigned by the IP address assignment unit and the unit information obtained by the unit information acquisition unit. as well as The information transmission and reception decision unit determines the form of information sent from the master station to the remote unit and the form of information received by the master station from the remote unit based on the network structure information updated by the network structure information update unit.

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