JP2004320195A - Remote i/o system in monitoring control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a remote I/O system for a monitoring control system in which changes in a program of each remote I/O station can be dealt with by only changing a program of a multiplexed control station. <P>SOLUTION: Each of control stations and remote I/O stations is provided with a common memory for sharing data, and each of them regularly broadcast-transmits the data of a transmission area of its own station assigned to the common memory to all other control stations and remote I/O stations at the time of acquiring a right of transmission. The controller of the control station writes I/O output data for the transmission area of its own station and reads the I/O data transmitted from the remote I/O station. The remote I/O station outputs the I/O output data transmitted from the control station, and stores the inputted I/O data into the transmission area of its own station, and transmits the stored data to the other control stations and the remote I/O stations. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a remote I / O system in a supervisory control system for industrial equipment, and more particularly to a remote I / O system in a supervisory control system multiplexed by a plurality of control stations such as a power system.
[0002]
[Prior art]
2. Description of the Related Art In public systems such as an electric power system, an electric railway system, and a water and sewage system, a multiplexed redundant high-reliability system is used to withstand continuous operation.
[0003]
For example, as shown in FIG. 4, control of a configuration in which three remote stations 120 for controlling a distant field device group 4 are operated in parallel by two control stations 101A and 101B via a transmission network 3. There is a system.
[0004]
Each of the plurality of control stations 101A and 101B has, for example, a programmable controller (PLC) 101a and a transmission unit 101b having a programmable function for controlling the system.
[0005]
Similarly, the remote I / O station 120 includes a controller having a similarly programmable function, and an input / output unit connected to the transmission unit and the field device group 4.
[0006]
The control stations 101A and 101B and the three remote I / O stations 120 are connected by respective transmission networks 3 and exchange messages including data with each other.
[0007]
The remote I / O station 120 exchanges data with the respective field device groups 4 and monitors the control stations 101A and 101B for abnormalities.
[0008]
The remote I / O station 120 performs (1) a process for selecting one of the two multiplexed control stations 101A and 101B, (2) a process for preventing erroneous output to the field device group 4, and the like. 3) A function such as an input / output control process for each of the different field device groups 4 is provided, and a different program is provided for each remote I / O station 120.
[0009]
In such a redundant monitoring and control system, if one of the control stations fails, the operation is continued at one of the other control stations, and the failed station is repaired during this time to stop the operation of the system. It is important to ensure the reliability of the system while maintaining the reliability of the system so that there is no problem and the program can be updated for the field devices that are updated daily.
[0010]
As such a method of changing a program of a duplicated control system, there is known a method of duplicating a CPU in order to continue operation and performing maintenance of the program during operation (for example, see Patent Reference 1).
[0011]
[Patent Document 1]
JP 2001-202101 A
[Problems to be solved by the invention]
In a multiplexed supervisory control system having a remote I / O station, a remote I / O station at a remote location requires a controller having a programming function and a transmission unit, like the control station. Therefore, it is necessary to maintain a program for each remote I / O station corresponding to a field device group that is updated daily, and a great deal of time is required for maintenance management.
[0013]
Conventionally, in such a system, although various methods for improving the efficiency of the program change operation are known, the program itself of the remote I / O station located at a place connected to the control station via a network is deleted. The technology for this is not known.
[0014]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem. In order to reduce programming provided for each remote I / O station, a control station and a remote I / O station are provided with a memory that can be shared. Provided is a remote I / O system in a monitoring and control system in which a system can be operated only by a program provided in a station and a program change of each remote I / O station can be dealt with only by a program change of a control station. The purpose is to:
[0015]
[Means for Solving the Problems]
In order to achieve the above object, a remote I / O system in a supervisory control system according to the present invention includes a supervisory control system in which a plurality of multiplexed control stations and one or more remote I / O stations are connected via a network. In the system, the control station and the remote I / O station each include a common memory for sharing data, and the control station and the remote I / O station are assigned to the common memory when each of them acquires a transmission right. The data of the transmission area of the own station is periodically broadcast to all the other control stations and the remote I / O stations, and the controller of the control station transmits the data to the transmission area of the own station in the common memory. Output data from the remote I / O station, and read input data sent from the remote I / O station from its own transmission area. The transmitted output data is output to each output module, and the input data input from the input module is stored in its own transmission area and transmitted to another control station and another remote I / O station. It is characterized by doing so.
[0016]
Therefore, even if one of the control stations fails, this monitoring and control system can always operate because the two control stations are operating in parallel, and can maintain the failed control station without stopping operation. It is.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
(First Embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows the configuration of the remote I / O system of the present invention. The two control stations 1 </ b> A and 1 </ b> B, which are operated in parallel, control the monitored controlled field devices 4 of the three remote I / O stations 2 via the transmission network 3.
[0018]
Each of the control stations 1A and 1B has the same configuration and includes a controller 1a and a transmission unit 1b.
[0019]
FIG. 2 shows the detailed configuration of the remote I / O station 2. The remote I / O station 2 includes a transmission unit 21 having a common memory 21d, an input / output control unit 22 for controlling the field device group 4, an input / output module unit 24, an input / output control unit 22, and an input / output module unit 24. It comprises a 1 / O bus 23 to be connected and a tool 25 of the transmission unit 21.
[0020]
The transmission unit 21 for executing the data transmission function between the stations has a common configuration in the control stations 1A and 1B and the respective remote I / O stations 2.
[0021]
The transmission section 21 converts a signal level to transmit and receive a transmission signal via the transmission network 3, a transmission / reception circuit 21 a, a transmission control circuit 21 b for controlling transmission / reception timing of a signal in the transmission network 3, CPU 21c and its work memory 21f for disassembly / interpretation and generation of data to be transmitted from the own station, and a common common for all stations storing received data from other stations and input data from the input module unit 24 transmitted by the own station. It is composed of a memory 21d, an RS-232C (Recommended Standard 232-C) 21g connected to a setting / monitoring tool 25, and a station address switch 21e for setting an address station in the transmission network 3.
[0022]
The input / output control unit 22 includes a CPU 22 a for controlling data transfer between the common memory 21 d of the transmission unit 21 and the input / output module unit 24, the memory 22 b, and an I / O bus for connecting to each module of the input / output module unit 24. It is composed of an interface 22c.
[0023]
In the input / output module unit 24, output modules 24a and 24b and input modules 24c and 24d are connected to an I / O bus interface 22c of the input / output control unit 22 via an I / O bus 23.
[0024]
Next, the overall operation of the remote I / O system of the monitoring control system configured as described above will be described. First, a communication operation between the control stations 1A and 1B and the remote I / O station 2 will be described.
[0025]
In order to output data to the output modules 24a and 24b of the remote I / O station 2, the controllers 1a of the control stations 1A and 1B write the data to the transmission area of the common memory of the transmission unit 1b of the own station.
[0026]
The written data is converted into transmission frame units by the transmission unit 1b, and is periodically broadcast to all other stations via the transmission network 3. The transmission units of the control stations other than the transmission station that has received the transmission frame write the received data in the same predetermined area of the common memory 21d.
[0027]
Similarly, in the remote I / O station 2, the input / output control unit 22 writes the data input from the input / output module unit 24 into its own transmission area, and the transmission unit 21 transmits the data to all other stations.
[0028]
In this way, as shown in the common memory map 201 of FIG. 3, the data transmitted by the transmission unit 21 of this system can be shared in the same memory map on the common memory of each station.
[0029]
As shown in FIG. 3 common memory map 201, fixed size areas are allocated to the transmission data from the control stations 1A and 1B and the memory areas of three (1 to 3) remote I / O stations 2 respectively. The transmission data from the control station is output data in the order of the mounting addresses of the output modules 24a and 24b mounted on the respective input / output module units 24 of the remote I / O station 2 as shown by reference numerals 202 and 203 in FIG. Written.
[0030]
Therefore, the remote I / O station 2 can recognize in advance the area of the data transmitted from the control stations 1A and 1B to the own station on the common memory 21d.
[0031]
On the other hand, the configuration of the transmission area of the transmission data transmitted from each of the three remote I / O stations 2 is notified by the tool 25 to the CPU 21C via the RS232C 21g, and the input module is indicated by reference numeral 204 in FIG. The addresses are set in the order of the mounting addresses of 24C and 24D.
[0032]
According to the common memory map 201 allocated in this way, the common memories 21d of the control stations 1A and 1B and the respective remote I / O stations 2 are mapped.
[0033]
Next, the operation of each unit of the remote I / O station 2 will be described. First, the operation of the transmission unit 21 will be described.
[0034]
The transmission unit 21 performs data transmission with the control stations 1A and 1B and other remote I / O stations via the transmission network 3. When transmitting the input data, the CPU 21c reads the data of the transmission area from the own station in the common memory 21d, and transmits the destination station address, the own station address, the type of the transmission frame, the data storage location, A transmission frame is created by adding a transmission header including a size and the like and an error code.
[0035]
Then, the transmission frame is transmitted to the transmission network 3 via the transmission / reception circuit 21a at the transmission timing when the transmission right is acquired. The transmission timing is detected by the transmission control circuit 21b. Depending on the transmission method, there are various methods such as CSMA / CD (Carrier Sense Multiple Access Detection), token passing, and polling. However, the present invention is not limited to this method.
[0036]
For example, the transmission employs a transmission whose transmission timing comes regularly, sets a global address as the destination of the transmission frame, and uses broadcast communication that can be received by all other stations constituting the system.
[0037]
The reception operation is as follows. The CPU 21c receives a transmission frame sent from another station via the transmission / reception circuit 21a and the transmission control circuit 21b, interprets the transmission header of the transmission frame, and stores the received data in the common memory 21d in FIG. Is stored in the predetermined area described in the above.
[0038]
At this time, an error detection process for checking the error code added to the transmission frame to check the normality of the frame, a process for discarding the received frame if abnormal, and a process for checking the content of the header to check the content of the common memory 21d And a reception confirmation process for checking whether or not the transmission frame from each transmission station is periodically received. At the address of the common memory 21d.
[0039]
Further, the CPU 21c is connected to the tool 25 via the RS-232C 21g port, and uses the tool 25 to set the transmission parameters for the remote I / O station 2, the setting of the transmission area of the remote I / O station 2, and the above-described setting. RAS (Reliability, Availability, Serviceability) information is read.
[0040]
Next, the operation of the input / output control unit 22 will be described with reference to FIG. The input / output control unit 22 executes data transfer between the common memory 21d of the transmission unit 21 and the input / output module unit 24.
[0041]
The CPU 22a of the input / output control unit 22 reads out the received data from the common memory 21d of the transmission unit 21, and outputs the data to the output modules 24a and 24b to the field device group 4.
[0042]
The input data from the input modules 24c and 24d is read out, and sequentially written from the top in the transmission area of the common memory 21d of the transmission unit 21 in the order of the mounting addresses in the input / output module unit 24 of the input modules 24c and 24d.
[0043]
The following information is communicated with the CPU 21c of the transmission unit 21 by using a specific part of the common memory 21d that is not used for data transfer. That is, the following information is transmitted from the transmission unit 21 to the input / output control unit 22.
[0044]
1. Transmission area of own station on common memory 21d (head address and size)
2. 2. Type of input / output module unit 24, mounting address A transmission healthy signal indicating the soundness of the other station. Also, the input / output control unit 22 transmits a healthy signal of each module of the input / output module unit 24 to the transmission unit 21.
[0045]
Based on these information, the input / output control unit 22 reads the data transmitted from the control stations 1A and 1B, determines whether the data is bit data or word data, and if the data is bit data, ORs the data. And output. In the case of word data, it performs arithmetic averaging processing and outputs it to the input / output module unit 24.
[0046]
The distinction between bit data and word data is determined by the type of the module to which this data is output. For example, if the output module 24a is a digital output module, it is determined as bit data, and if it is an analog module, it is determined as word data.
[0047]
In the above description, the transmission area of the remote I / O station 2 is freely set by the tool 25, but the transmission area of a certain range is automatically set on the common memory 21d by the station address of the remote I / O station 2. The tool 25 is used by allocating and using the mounting address of each module read out when a healthy check of each module of the input / output module unit 24 is performed when the configuration of the transmission area of the remote I / O station 2 is initialized. It is also possible to automatically set the setting of the transmission area from.
[0048]
Further, the transmission unit 21 interprets the received transmission frame from the other station and stores the data in a predetermined area of the common memory 21d. At this time, the transmitting station address, the common memory 21d of the transmitted data, The storage address and the memory size are stored.
[0049]
Therefore, since the area of the common memory 21d used for each station transmitting data is mapped as described with reference to FIG. 3, it can be detected that the area of the assigned transmitting station address is duplicated. In addition, when the duplication is detected, the duplicate transmission frame is discarded, and when the duplication is in the area of the own station, the transmission from the own station is stopped, and an abnormal signal indicating that the duplication to another station is made. And set the operation mode of the own station to the offline state.
[0050]
As described above, according to the present embodiment, it is not necessary for a remote I / O station conventionally configured with a controller having a programming function and a transmission unit to produce a program for each station. It can be replaced by a remote I / O station. As a result, the remote I / O station can be configured as a system that can be operated only by simple settings, and thus the engineering work involved in programming is reduced.
[0051]
Further, if the transmission area of the remote I / O station is fixedly given by the station address, and the configuration of the input / output data is created in the order of the mounting address, the setting by the tool becomes unnecessary, and the work of the remote station is further reduced.
[0052]
In addition, since overlapping transmission areas can be detected, system incompatibility due to incorrect setting of station addresses can be detected quickly, and system startup becomes easy.
[0053]
In this embodiment, the number of control stations is 2 and the number of remote I / O stations is 3, but the present invention is not limited to these numbers.
[0054]
【The invention's effect】
As described above, according to the present invention, the maintenance work of the program can be reduced, and the reliability of the monitoring control system can be improved.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of the present invention.
FIG. 2 is a configuration diagram of a remote I / O station according to the embodiment of the present invention.
FIG. 3 is a memory map of a common memory according to the embodiment of the present invention.
FIG. 4 is a configuration diagram of a conventional system.
[Explanation of symbols]
1A, 1B Control station 1a Controller 1b Transmission unit 2 Remote I / O station 3 Transmission network 4 Field device group 21 Transmission unit 21a Transmission / reception circuit 21b Transmission control circuit 21c CPU
21d Common memory 21e Station address switch 21f4 Memory 21g RS232C
22 input / output control unit 22a CPU
22b memory 22c I / O bus interface 21c input / output module 23 I / O bus 24 input / output module unit 24a, 24b output module 24c, 24d input module 101A, 101B control station 101a controller 101b transmission unit 120 remote I / O station 120a transmission Unit 120b controller 120c input / output unit

Claims (4)

In a monitoring and control system in which a control station including a plurality of multiplexed controllers and transmission units and one or a plurality of remote I / O stations are connected via a network,
The control station and the remote I / O station each include a common memory for sharing data,
The control station and the remote I / O station transmit the data of the transmission area of the own station allocated to the common memory to all the other control stations and the remote I / O stations when each has acquired the transmission right. Broadcast periodically,
The controller of the control station writes output data to its own transmission area of the common memory, reads out input data sent from the remote I / O station from its own transmission area,
The remote I / O station outputs the output data sent from the control station to each output module, stores the input data input from the input module in its own transmission area, and stores the data in the other control station. And a remote I / O system in the supervisory control system, wherein the remote I / O system transmits the data to another remote I / O station. The same bit data sent from the plurality of control stations is output to an output module by a predetermined logic in each of the remote I / O stations, and the same word data is arithmetically processed in each of the remote I / O stations. 2. The remote I / O system in the supervisory control system according to claim 1, wherein an average is output to each output module. 2. The remote I / O station according to claim 1, wherein the transmission area of the remote I / O station is fixedly assigned a transmission area as a station address of each of the remote I / O stations. O system. The remote I / O station stops output from the local station when the preset transmission area of the local station and the transmission area of data transmitted to the local station overlap, and the remote I / O station has overlapped. 4. The remote I / O system in the supervisory control system according to claim 3, wherein the remote I / O system is transmitted to another station.

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