JPH08106301A - Plant process control system - Google Patents

Abstract

PURPOSE: To facilitate the maintenance and inspection operation, etc., for a plant by providing processors of a triple system, data transmission lines of the triple system, and plural terminal equipments which send and receive signals among plant processes. CONSTITUTION: The data transmission lines 2 of the triple system are connected to the processors 1 of the triple system which perform predetermined processes for respective control loops, and electric connections with the data transmission lines 2 are made so that the plant processes 3 can be sent and received through field terminal equipments 4 for the triple system and field terminal equipments 5 for a double system. Then a console panel 12 for controlling the states of the electric connections between the processors 1 of the triple system and the plant processes is connected. Through operation on the console panel 12, modes for the respective control groups A-N are set by the control loops, which perform specific arithmetic operations to send and receive the signals of the field terminal equipments 4 and 5 to and from the respective processors 1. The maintenance and inspection operation for the plant can easily be done.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system configured to include at least a redundant terminal device, a transmission line, and a processing device for controlling a plant process. Regarding a system provided with.

[0002]

2. Description of the Related Art Conventionally, there has been proposed a system in which a control system for controlling a plant process has a redundant structure and the function is not lost even if a part of the system fails. Was there.

As an example of the configuration of such a system, a general configuration is one in which an optical multiplex transmission line is connected to a terminal device that transmits and receives signals to and from a plant process, and further the optical multiplex transmission line is connected to a control processing device. is there. Each of the control processing device, the optical multiplex transmission line and the terminal device has a triple redundant configuration.

As a result, the terminal device inputs the signal from the plant process, sends the signal to the control processing device through the optical multiplex transmission line, and the control processing device outputs the output from the plant process. Perform predetermined processing based on the signal, and give a signal according to the processing result to the plant process via the optical multiplex transmission line and the terminal device,
The control loop for performing a series of controls also had a triple redundant configuration.

In this case, all the control loops have a triple redundant configuration so that even if a failure occurs in a part of the system, operation is performed so that the function of the entire plant is not lost. The fault tolerance function was realized.

With this fault tolerance function, for example, when one of the triple systems fails, degenerate operation is performed from the triple system to the double system. Note that such a technique is a publicly known and publicly-used technique, and a plant control system in which a control loop has a triple redundant configuration is adopted in various industrial fields such as chemistry and nuclear power.

[0007]

However, in the above-described plant control system in which the control loop has a triple redundant structure, although it has an excellent fault tolerance function, as a matter of course, the system hardware The scale of the wear increases and it is impossible to make the entire system smart. In addition, there is a problem that the system cost becomes high.

It is also conceivable to configure all control loops in a redundant system, which is the minimum number of redundancy for realizing the fault tolerance function. In this case, all the control loops as described above are Compared with a system in which the control loop has a triple redundant configuration, the system scale and cost are not increased, but the reliability is inferior.

Particularly, in a chemical plant, a nuclear power plant or the like, when the control operation for the control loop becomes abnormal,
A triple redundant system is often used for a control loop that is directly connected to the loss or deterioration of the function of the entire plant.

Therefore, an object of the present invention is to refer to the characteristics of the control system and to appropriately change the redundancy number of the control loop so that different redundancy configurations, that is, redundant configurations of triple system and double system are mixed. And to provide a means for solving the above problems.

Further, it also provides means for maintenance and inspection work while operating the plant, which has not been proposed by such means.

[0012]

The following means are conceivable as means for solving the above problems and achieving the object of the present invention.

That is, a system having a plurality of control loops, each control loop transmitting and receiving a signal to and from a plant process to be controlled to control the plant process, and predetermined for each control loop. Means provided with a triple processing device for performing the above processing, a triple data transmission line connected to each processing device, and a plurality of terminal devices for transmitting and receiving signals to and from the plant process.

Further, a part of all the terminal devices is
It is configured as a triple system device connected to each of the triple system data transmission lines, and the remaining terminal devices are connected to two system data transmission lines of the triple system data transmission lines. It is configured as a dual system device, and each control loop is a means including a processing device, a data transmission line, a terminal device, and a plant process.

Further, the following modes are also possible.

That is, in addition to the above-mentioned means, any one of at least one or more modes prepared in advance indicating the electrical connection state with the plant process is set for each control loop. An electrical connection between a terminal device and a plant process that form a corresponding control loop so that a preset electrical connection state for the set mode is established when the mode is set. It is a means provided with a state setting means for setting the state to a predetermined state.

[0017]

The present invention has a plurality of control loops, and each control loop controls the plant process by transmitting and receiving signals to and from the plant process to be controlled.

Here, each control loop includes a processing device, a data transmission path, a terminal device, and a plant process.

The triple processing device performs a predetermined process for each control loop, and the plurality of terminal devices send and receive signals to and from the plant process.

That is, according to the instruction from the processing device,
The terminal receives the signal from the plant process,
This is given to the processing device via the data transmission path. The processing device performs predetermined predetermined processing based on the given signal, gives a signal corresponding to the processing result to the plant process via the data transmission line and the terminal device, and controls the plant process. To do.

Of all the terminal devices, the triple system device connected to each of the triple system data transmission lines functions as a device in which the control loop is tripled.

The dual system device connected to the dual system data transmission line among the triple system data transmission lines functions as a device in which the control loop is duplicated.

The terminal devices involved in particularly important control are
By adopting a configuration of a heavy system device and a mixture of a dual system terminal device, a rational and economical system can be realized and the scale of hardware can be made smart.

Further, the mode setting means selects and sets a desired mode, and the state setting means sets the electrical connection state between the terminal device and the plant process forming the control loop to a predetermined state. As a result, for example, a signal is transmitted and received between the terminal device forming the control loop and the plant process to electrically connect them (online mode), and the terminal device forming the control loop and the plant process are connected. It becomes possible to stop the transmission and reception of signals between the two and electrically separate them (bypass mode), etc., and facilitate the maintenance and inspection work of the plant.

[0025]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the configuration of the entire system according to the present invention.

In this embodiment, a triple system processing device 1, a triple system optical multiplex transmission line 2 connected thereto, and a triple system field terminal connected to the optical multiplex transmission line 2 are provided. Devices 4 and 2
It is configured to have an operation panel for controlling the electrical connection state and the like connected to the heavy system site terminal device 5 and the processing device, and to the plant process 3.

The triple system field terminal device 4 (hereinafter, simply referred to as the field terminal device 4 as appropriate) is configured to have a triple system voter 8 and a process signal interface 10.
On the other hand, the dual-system field terminal device 5 (hereinafter, simply referred to as the field terminal device 5 as appropriate) is configured to include a dual-system voter 9 and a process signal interface 11.

Then, a signal is exchanged between the plant process 3 to be controlled and the on-site terminal device 4 for triple system and the on-site terminal device 5 for dual system, and this system controls the plant process 3. There is.

Although not shown, the plant process is
A plurality of sensors for detecting a physical quantity (plant process data) indicating the state of the plant and a plurality of actuators for setting the state of the plant to a desired state are provided.

The output signal of each sensor becomes an output signal from the plant process, and the process signal interface provided in either the triple system field terminal device 4 or the dual system field terminal device 5 inputs the input signal. Accept as. In addition, the signal given to each actuator is
As an input signal to the plant process, a process signal interface provided in either of the triple system field terminal device 4 and the dual system field terminal device 5 is supplied.

The output signal of each sensor is automatically stored in a predetermined area in the memory of each processing device via the corresponding terminal device and optical multiplex transmission line, and the output signal of the sensor is The data is updated sequentially. Similarly, the processing result of a predetermined program executed by each processing device based on the sensor signal is also stored in a predetermined area in the memory, and the storage result is automatically stored in the corresponding terminal device or optical multiplexer. It is supplied to the actuator as a control signal for the actuator via the transmission line.

A feature of the configuration of this embodiment is that the triple system field terminal device 4 and the dual system field terminal device 5 coexist and control the plant process. .

Now, the processing unit 1 performs arithmetic processing according to a predetermined algorithm for each of the plurality of control loops A, B, C ... Here, the processing devices have a triple redundant configuration, and the three processing devices 1
Have exactly the same configuration and perform the same arithmetic processing.

The term "control loop" as used herein means that a state signal of a plant process is taken in, a calculation process is performed according to a predetermined algorithm based on the state signal, and a control signal is sent to an actuator included in the plant process in accordance with the calculation result. Is a closed loop system that controls the plant process by outputting.

That is, the control loop according to the present embodiment includes a sensor, a terminal device that receives an output signal from the sensor, and gives a control signal to an actuator, an optical multiplex transmission line that transmits various signals, and various calculations. And a processing device having at least a function of performing processing.

By assigning the triple-system field terminal device 4 or the dual-system field terminal device 5 to each control loop, the redundant configuration of each control loop is set to the triple system or the dual system. For example, the triple system site terminal device 4 is assigned to the control loop A, and a triple system redundant configuration is provided, and the remaining control loops B, C, ... As an example, it may be considered that the terminal device 5 is allocated and the system has a dual redundant configuration.

Even if the number of control loops is larger than the number of field terminal devices, one field terminal device may be configured to allocate a plurality of control loops.

Generally, in order to perform automatic operation while controlling a plant, it is necessary to operate a large number of control loops in real time and continuously.
The control is executed according to a predetermined algorithm in correspondence with the steady operation, the stopping operation, the operation in response to the abnormality, and the like. Taking a nuclear plant as an example, it usually has several thousand or more control loops.

Generally, the operation mode of the control loop includes an online mode, a fail safe or fail as is mode, an offline mode, and a bypass mode.

Although a detailed description of each mode will be given later, these modes are set for each control loop by operating the operation panel 12.

Specifically, the mode is set for the control loop by turning on the switch 7 corresponding to the mode to be set. It is to be noted that the setting of the mode can be confirmed by turning on a status indicator lamp such as an LED.

As described above, the processing device 1 has a triple system redundant configuration, and each control loop A, B, ..., N.
The arithmetic processing for is sequentially executed.

On the other hand, in this control system, the plant process and the on-site terminal devices 4, 5 are electrically connected,
The state signal, which is a signal indicating the state of the plant process, is taken in (that is, the sensor signal is obtained) and the control signal for the actuator is supplied.

Further, the processing device 1 and the on-site terminal devices 4, 5
The various signals are exchanged with the optical transmission system 2 having a triple redundant structure.

Therefore, the field terminals 4 and 5 need to be properly connected to the triplex optical multiplex transmission, which is performed as shown below.

That is, when the state signal of the plant process is taken in, the process signal interface provided in the field terminal devices 4 and 5 converts the analog signal output from the sensor into a digital signal, and further converts the digital signal into parallel / serial. Then, the serial digital signal is converted into electrical / optical signals and sent to the optical multiplex transmission line of the triple system.

On the other hand, in the case of outputting a signal to the plant process, the process signal interface provided in the field terminal devices 4 and 5 is received from the processing device 1 received via the optical multiplex transmission line 2 of the triple system or the dual system. Photoelectric conversion of the optical signal of to electrical signal, the electrical signal is converted to serial / parallel,
(When the destination of the optical signal from the processing device 1 is the field terminal device 4), it is given to the voter 9 (when the destination of the optical signal from the processing device 1 is the field terminal device 5).

Although not shown, each processing device 1 is provided with an interface circuit, which converts an optical signal sent from the field terminal device side into an electric signal and stores it in a predetermined storage area in the memory. To generate an optical signal corresponding to the data stored in the
It has at least the function of sending to the field terminal device side.

The voters 8 and 9 are respectively based on the data of 3 (field terminal device 4) and 2 (field terminal device 4).
A process using a majority logic is performed, and a control signal for operating an actuator included in the plant process is supplied based on the process result. Various methods can be considered as the majority logic used by the voters 8 and 9 for processing, and an example thereof will be described later with reference to FIG.

As described above, in the control system according to the present invention, the field terminal device 4 having the triple optical multiplex transmission line and the field terminal device 5 having the dual optical multiplex transmission line are provided. Are mixed and share the optical multiplex transmission line 2.
The reason for adopting such a configuration is to properly use the redundant configuration of the control loop.

That is, the system important as a control loop has a triple system, and the other control loops have a double system.

In general, the proportion of control loops that need to have a triple redundant configuration in all control loops is small.
Properly arranging the control loop of the heavy system, that is, coexisting the field terminal device 4 having the optical multiplexing transmission line of the triple system and the field terminal device 5 having the optical multiplexing transmission line of the dual system, There is an effect that a fault tolerance function for a particularly important control system can be maintained while suppressing an increase in system scale and an increase in system cost.

Further, the signal amount of the plant process relating to one control loop and the processing response time by the processing device are also important parameters when constructing such a system.

That is, when the amount of signals in the plant process increases, the number of times signals are exchanged with the plant process also increases, which leads to an increase in the scale of the hardware constituting the field terminal device, and in some cases, in the field. In some cases, the number of terminal devices installed may have to be dealt with, and the transmission speed of data transmitted through the optical multiplex transmission line depends on the number of terminal devices in the field. The processing response time also becomes large.

Further, when the degree of change in the signal of the plant process becomes large, the data sampling frequency must be made high, the amount of data transmitted in the optical multiplex transmission line becomes large, and the processing response by the processing device deteriorates. To do.

Therefore, whether a triple system or a double system is adopted as the redundant configuration of the field terminal device, that is, a certain control loop is a triple system or a double system is used. Whether or not to take into consideration not only the importance in the control system of the control loop, but also various parameters such as the signal amount of the plant process data, the changing speed of the signal, and the response required for the control system. It is necessary to make a decision, and the system is constructed by the optimum engineering judge.

The importance of the control loop in the control system is determined by the magnitude of the influence on the entire control system when an abnormality occurs in the control loop.

Now, an example of control operation by the control system shown in FIG. 1 will be described below.

In the present control system, the control loop A operates as a triple system as an important control loop, and is assumed to be set to the online mode now.

Further, the control system loop B operates in the dual system and is now set to the online mode, and the control system loop C (not shown) operates in the dual system. , It is assumed that the mode is set to bypass mode. The mode setting will be described in detail later, but in brief, the online mode is a mode for performing normal control operation, and the bypass mode separates the electrical connection between the field terminal device and the plant process, This is a mode in which the control operation for the plant process is not performed.

On-site terminal device 4 is assigned to control loop A to form a triple control loop, and on-site terminal devices 5 are assigned to control system loops B and C, respectively. A heavy system control loop shall be constructed.

The above-mentioned setting of the mode for each control loop A, B, C is performed for each control loop by operating the operation panel 12. Specifically, the switch 7 corresponding to the control loop setting mode is turned on.
Whether the setting is correct or not is confirmed by turning on the status indicator lamp.

At the same time, the three processing devices 1 perform predetermined arithmetic processing according to the processing algorithm for the control loop A and the control loop B, and the field terminal devices 4 and 5 corresponding to each control loop and the optical multiplex transmission. Signals are exchanged via the path 2.

First, the status signal of the plant process 3 (the output signal of the sensor provided in the plant) is automatically
For example, the data is sent to and stored in a predetermined storage area in the memory of each processing device 1 via the field terminal devices 4 and 5 and the optical multiplex transmission path 2 at predetermined time intervals.

The processing apparatus 1 performs arithmetic processing according to a predetermined algorithm for each of the control loop A and the control loop B based on the signal sent from the plant process 3 and stored therein, and the processing The result is stored in a predetermined storage area in the memory as a control signal for the actuator.

The interface circuit provided in each processing unit 1 sends the stored control signal of the actuator to the field terminal units 4 and 5 through the optical multiplex transmission line 2.

Then, the voters 8 and 9 supply the processing result using the majority logic as an actuator control signal to the actuator provided in the plant process.

By repeating the above operation,
The control loop A and the control loop B execute control of the plant process.

On the other hand, as for the control loop C, since this loop is set to the bypass mode, the field terminal device which is assigned to this control loop via the optical multiplex transmission line 2 is set to the bypass mode. Tell 5. The field terminal device 5 recognizes that the control loop C is set to the bypass mode and sets the electrical connection state of the control loop C with the plant process to the separated state. In addition,
In order to notify that the bypass mode is set, the processing device 1 transmits predetermined data representing the bypass mode setting to the process signal interface 11 of the field terminal device 5, and the process signal interface 1
1 may interpret the data received and detect the bypass mode setting. With respect to the other mode settings, the field terminal device may be notified of the setting mode for the control loop with the same configuration.

The processor 1 may be programmed so as not to perform the arithmetic processing performed according to the algorithm for the control loop C, or the newest data (bypass mode setting) may be set according to the algorithm for the control loop C. Last data: If the bypass mode is set at the same time when the system starts up,
It is conceivable that a preset initial value) is taken out from the memory, and the result of the arithmetic processing performed according to the algorithm is repeatedly stored in the memory, that is, the processing which is the same as usual is performed.
Of course, since the bypass mode is set, the control operation using the processing result is not performed.

A similar idea may be adopted for the calculation of the triple processing unit performed on the double control loop. In other words, when the control loop is a triple system, it makes sense to have three processing units perform calculations, but when the control loop is a double system, it is connected to a triple optical multiplexing transmission line. Of the three processing devices, only two processing devices are connected to the field terminal device.
It does not make sense to have the three processors perform the calculations.

In this way, for the control loop of the double system, two processing devices are previously assigned to the control loop, and the calculation results of the two assigned processing devices are used,
The remaining processing devices may be configured to take out the newest data from the memory and repeat the normal processing of storing the arithmetic processing result performed according to the algorithm in the memory. Of course, the control operation using the processing result of this processing device is not performed, and the calculation that is not related to the control operation is repeatedly performed to synchronize the processing timing with other processing devices.

As described above, the operation of the control system in which the dual and triple control loops coexist is performed.

By the way, in the case of having a large number of control loops,
It is possible to perform control operations with this system. At this time, if the on-site terminal devices 4 and 5 are provided for each control system loop, the number of on-site terminal devices increases in proportion to the number of control loops, leading to an increase in hardware scale. This will increase the system cost.

On the other hand, in principle, a plurality of control loops are
If the configuration is such that one field terminal device is shared, the cost will not increase so much, but the operability during maintenance and inspection work will deteriorate.

In order to set a specific control loop in the bypass mode and perform maintenance / inspection, it is necessary to separate the electrical connection state between the plant process 3 and the field terminal device related to the control loop. The electric connection state between the plant process 3 and the field terminal device for other control loops sharing the field terminal device is also separated, which causes a problem.

Therefore, in consideration of the operation of the plant process, a control loop that can be simultaneously maintained, that is, a bypass mode can be set at the same time to perform maintenance work is selected from all control loops, and the control loop is selected. , Group into some groups beforehand. Then, it is desirable to determine a site terminal device to be assigned to each group and construct a system.

That is, control loops, which are units of maintenance work, that is, by setting the bypass mode at the same time and capable of maintenance work, are grouped together and the field terminal devices to be assigned to one group are determined to construct a system. Is preferably performed.

Further, in general, the plant process 3 employs a redundant configuration for the essential steps for maintaining the operation function of the plant.

Therefore, even if a failure occurs in an essential process, since the redundant configuration is adopted, the redundant process part is normally placed in a standby state, and the switching process is performed so that this is adopted when a failure occurs. Or lower the performance level and continue operating the plant.

In this case, with respect to the redundantly configured process,
For the relevant control loop, bypass management for each group, that is, for all control loops belonging to the group,
By operating the operation panel 12, the bypass mode may be set and maintenance work or the like may be performed.

Next, various modes that can be set for the control loop will be described.

First, in the memory provided in each processing unit 1, a mode control program for controlling the mode and a plant control program for performing arithmetic processing according to a predetermined algorithm for each control loop. Is stored.

The operations of the processing device (FIG. 2) and the on-site terminal device (FIG. 3) performed according to the mode control program will be described below. In FIG. 2, the operation of the processing device 1 in each mode is described, and in FIG. 3, the operation of the field terminal devices 4 and 5 is described.

First, by starting the mode control program, it is possible to set each mode of online, offline, fail-safe or fail-ize, and bypass for each control loop. After starting the system, the operator operates the switches on the operation panel to set the mode for each control loop.

Then, the processing apparatus 1 performs step 1 in FIG.
At 00, the setting state of the switch on the operation panel is read to grasp which mode is set.

On the other hand, the field terminal device forming the control loop receives the data indicating the setting mode sent from the processing device via the optical multiplex transmission line in step 200 of FIG. 3 and sets the set mode. Receive and understand the contents of.

If the set mode is the online mode, the process branches to step 110 in FIG.
Is electrically connected to a plant process via a field terminal device forming a control loop to execute a plant control program.

On the other hand, the on-site terminal device is step 21 in FIG.
At 0, an operation of electrically connecting to the plant process, receiving a signal from the process and sending it to the processing device 1, and a normal control operation of outputting the signal from the processing device 1 to the process are performed.

Next, when the set mode is the fail safe / fail as is mode, step 1 in FIG.
Branching to 20, the processing device 1 executes the plant control program and instructs the corresponding field terminal device that the fail safe / fail as is mode has been set.

On the other hand, the on-site terminal device uses the step 22 shown in FIG.
At 0, all input signals from the plant process are electrically isolated. Then, the state of the output signal given to the plant is set to a predetermined state so that the control trend of the plant process tends to be stable.

Specifically, the fail-safe setting control loop is electrically separated from the plant process, and the fail-ize setting control loop is supplied with a predetermined output signal. Performs the operation of electrically applying to the plant process.

The fail-ize is a mode for causing the plant to perform the following operation, for example. Assuming a plant equipped with a solenoid valve in the pipe through which water flows and controlling the solenoid valve to control the water flow, the power supply to the solenoid valve is lost due to some abnormality and the water flow is shut off. Suppose you want to move. At this time, as a process, when it is in the stable direction of the plant that the water always flows through the pipe, the operation panel 12
If the fail-ize mode is set by the operation of, the field terminal devices 4, 5 supply current to the solenoid valve so that the power supply to the solenoid valve is not lost in any case. Performing a control action
It becomes a fail as is operation.

Next, when the set mode is the off-line mode, the process branches to step 130 in FIG. 2 so that the processing device 1 electrically separates the corresponding on-site terminal device from the plant process. Instruct the on-site terminal device. Then, the processing device 1 executes the above-mentioned plant control program using the simulated plant process data stored in advance.

On the other hand, the on-site terminal device is step 23 in FIG.
At 0, the operation of electrically separating the input signal and the output signal from the plant process is performed.

The execution of the plant control program in the processor 1 using the simulated plant process data will be described.

This mode is used, for example, when the plant control program is changed, to confirm whether or not the changed plant control program functions correctly.

That is, this is a mode used to preset simulated plant process data and use this data to confirm whether or not the desired calculation and generation of an output signal are performed.

Here, a specific example of the simulated plant data will be described. Generally, the plant process includes start-up operation, steady operation, stop operation operation, abnormal operation,
It has operation modes such as monitoring operation at stop. And
There is a respective plant control program for each operating mode. Therefore, data representing a typical plant state and normal output data when the plant control program is executed using this data are created in advance and used as simulated plant data.

That is, the input data and the output data that will be output if the plant control program is normal when the input data is given are set as simulated plant process data, and the simulated plant process data is set. Check the validity of the program based on the execution result of the plant control program.

When the program is judged to be invalid, a warning to that effect may be given at a predetermined position on the operation panel and an indicator lamp may be provided.

Next, when the set mode is the bypass mode, the process branches to step 140 in FIG. 2 and the processing device 1 stops the execution of the plant control program and the bypass mode is set to the corresponding field terminal device. Indicates that it has been set.

On the other hand, in the same way as the off-line mode, the field terminal device electrically separates the input signal and the output signal from the plant process in step 230 of FIG.

The main use of this mode is to stop the execution of the plant control program for the control loop,
Maintenance of the plant process, which constitutes the control loop,
It is in performing inspection work.

In particular, the entire plant is in operation,
When an abnormality occurs in a specific control loop, the part that constitutes this control loop is separated from the plant process, however, while maintaining the operation of the plant itself, maintenance, inspection of the part related to the control loop in the abnormal state, For example, it is used when confirming the adequacy of repair content after repair. In addition, in nuclear power plants, etc., in most cases, important components are often redundantly configured, and an abnormal state occurs. Even if the plant components are disconnected, so-called degenerate operation is performed to operate the entire plant. It is possible to continue.

FIG. 4 is a configuration diagram showing a configuration example of the process signal interfaces 10 and 11 provided in the field terminal devices 4 and 5.

With reference to FIG. 4, a mechanism for generating an electrically separated state from the plant process 3 will be described in particular. It is assumed that the bypass mode is set now.

Now, considering the field terminal device 4 in particular, when the field terminal device 4 receives the signal indicating the bypass mode setting from the operation panel 12 via the optical multiplex transmission line 2 of the triple system, The optical multiplex transmission control unit 13 having an interface function between an optical signal and an electric signal converts the received optical signal into an electric signal, and converts the converted signal into a voter processor 14
Give to.

The boat processor 14 is also connected to the gate circuit 16 via a buffer amplifier.

In the gate circuit 16, a relay driver is provided for each of the process input signal 101, which is the input signal from the process to the field terminal device, and the process output signal 102, which is the output signal from the field terminal device to the process. It is equipped with it.

When the boat processor 14 receives the signal indicating the bypass mode setting, the bypass command signal 15
Is applied to a predetermined relay drive unit included in the gate circuit 16.

The relay drive unit supplied with the bypass command signal 15 separates the electrical connection state between the signal line transmitting the process input signal 101 and the process output signal 102 and the signal line connected to the buffer amplifier. FIG.
Explains the field terminal device 4 of the triple system,
The same operation is performed for the dual site terminal device 5.

FIG. 5 shows a flow of redundancy control in the field terminal devices 4, 5.

Note that such a processing program is provided in each of the on-site terminal devices 4, 5 and each of the on-site terminal devices 4, 5
Performs the operation according to the provided processing program.

First, in step 500, it is determined whether the configuration of the optical multiplex transmission line for the field terminal device is a double system or a triple system.

As a result, it can be known whether the optical multiplex transmission line connected to the field terminal device is a triple system or a double system, and the control operation will be changed depending on the redundancy.

If the optical multiplex transmission line is a triple system, the process branches to step 510, and it is determined whether or not one of the triple system control loops is abnormal.

When the whole system is normal, the process input signal from the process to the field terminal device is three systems, that is,
Engineering value data (physical quantity indicated by an input signal) is transmitted to the triplex optical multiplex transmission line. Then, for the digital signal, the output signal from the field terminal device to the plant process is generated by using the 2 out of 3 logic, and for the analog signal, the intermediate value of the engineering value data of 3 systems is generated. , Output signal (step 520).

It is determined whether or not one of the triple systems is abnormal or all of the double systems are normal (step 53).
0) As a result, when the control operation is performed in the dual system, the input signal from the plant process to the field terminal device is a normal two system, that is, an optical multiplex transmission line of the dual system has an engineering value. Transmit data.

The output signal to the plant process is output according to a predetermined rule.

Specifically, for digital signals,
An AND or OR logic is used to generate an output signal from a field terminal device to a plant process, and for an analog signal, a high value (larger value) or a low value of two engineering value data The (smaller value) is used as the output signal (step 540).

In step 550, the triple system,
If, as a result, only the single system is judged to be normal despite the provision of the dual system control loop, the plant process input signal, plant Process input signals are exchanged (step 560).

As an important control loop, when the control other than the redundant configuration is not permitted, that is, when the control operation in the single system is prohibited, step 5
The same control operation as in the case of the entire system abnormality shown in 70 is performed.

Next, in step 550, when it is determined that the entire system is abnormal, it is necessary to keep the plant process in a stable direction. Therefore, a preset setting, that is, fail safe or fail ize operation is performed. So that a signal is output to each plant process.

All input signals from the plant process to the field terminal equipment are electrically separated and not accepted (step 570).

In the processing device, a sending flag which is set when data is sent and a receiving flag which is set when response data is returned are set.
Despite the fact that the sending flag has been set, it is possible to detect the occurrence of a failure in the control loop by grasping the state in which the receiving flag is not set within the predetermined time, and the information indicating that the failure has been detected is By sending it to the field terminal device that constitutes the control loop, the field terminal device can grasp the failure state of the redundant configuration of the device itself.

Next, FIG. 6 shows how the arithmetic operations corresponding to the respective control loops are sequentially executed in the processor 1.

Execution of each control loop operation is performed according to a plant control program which is predetermined corresponding to each control loop. Further, the control loop state table is configured such that the result of each control loop calculation execution is stored in the storage area provided for each control loop. In the storage area, plant process data (data detected by a sensor) is automatically stored by the interface circuit for each control loop, and the processing result is automatically provided by the interface circuit in the plant process. Given to the actuator.

Therefore, by executing the plant control program corresponding to each control loop, the plant process data stored in the corresponding storage area is read, and the data obtained by the predetermined process using this data is
The process of storing in the corresponding area of the control loop status table
We will do it in sequence.

As a result, it is not necessary to consider the time synchronization between the processes performed for each control loop, and it is only necessary to be aware of the order of execution of operations.

This state is shown in FIG. 6. The operation for "control loop A" is executed next, the operation for "control loop B" is executed, and then the operation for "control loop C" is executed. The processes to be executed are executed in a predetermined order.

On the other hand, when the hardware for performing the arithmetic processing for each control loop is divided,
This causes the phenomenon of desynchronization of the arithmetic processing, so that the order of the arithmetic processing is desired such as "control loop A", "control loop C", then "control loop B". It is also possible that the order will be disturbed.

As shown in FIG. 6, the state (calculation result) of each control loop, the transmission data to other control loops, etc. are written in a predetermined area of a predetermined table, and other control loops are controlled. By reading the data received from the loop from the corresponding area, the system can be designed without being aware of synchronizing various processes.

Conventionally, hardware for performing arithmetic processing is provided for each control loop, and each hardware performs arithmetic operation by an individual clock, and data exchange between control loops is performed asynchronously. Therefore, it is necessary to provide means for taking into account the synchronization of various processes, but such means is generally complicated.

In addition, the time margin must be sufficiently considered in order to synchronize various processes. In particular, in a redundant system, complicated hardware and software are necessary for coping with an abnormal condition while synchronizing various processes. According to the present invention, an extremely simple structure can be achieved.

According to the present invention as described above, 2
The control system loops of the heavy system and the triple system are coexistent, and it is possible to perform rational control of the entire plant with a simple and inexpensive hardware configuration.

Further, the electrical connection between the plant process and the control system can be brought to a desired state, and maintenance of a specific portion of the plant process and inspection work can be facilitated.

Furthermore, since the predetermined processing performed for each control loop is sequentially performed, it is not necessary to consider synchronization with the processing performed by each processing device.

[0140]

EFFECTS OF THE INVENTION By making the control loops of the double system and the triple system coexist, it is possible to perform rational control of the entire plant with a simple and inexpensive hardware configuration.

Further, the electrical connection between the plant process and the control system can be set to a desired state, and maintenance of a specific part of the plant process and inspection work can be facilitated.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an example of the overall configuration of a system according to the present invention.

FIG. 2 is an explanatory diagram of processing performed for each mode.

FIG. 3 is an explanatory diagram of processing of a field terminal device performed for each mode.

FIG. 4 is a configuration diagram of a field terminal device, a plant process, and a connection unit.

FIG. 5 is a flowchart showing a redundancy control process in the field terminal device.

FIG. 6 is an explanatory diagram of a processing procedure performed by the processing device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Processing device, 2 ... Optical multiplex transmission line, 3 ... Plant process, 4 ... Triple system field terminal device, 5 ... Dual system field terminal device, 6 ... Status indicator, 7 ... Switch, 8 ... Triple system Boat, 9 ... dual system boat, 10 ... process signal interface, 11 ... process signal interface, 12 ...
control panel,

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuko Takahara 5-2-1 Omika-cho, Hitachi-shi, Ibaraki Hitachi Ltd. Omika factory

Claims (4)

[Claims] 1. A system having a plurality of control loops, each control loop transmitting and receiving a signal to and from a plant process to be controlled to control the plant process, and the system is predetermined for each control loop. And a plurality of terminal devices for transmitting and receiving signals to and from a plant process, and a triple system processing device for performing the above processing, a triple system data transmission line connected to each processing device, A part of them is a triple system device connected to each of the triple system data transmission lines, and the remaining terminal devices are data of two systems of the triple system data transmission lines. A plant process control, which is a dual-system device connected to a transmission line, and each of the control loops includes a processing device, a data transmission line, a terminal device, and a plant process. System . 2. The method according to claim 1, further comprising, for each control loop, at least one or more modes prepared in advance that indicate an electrical connection state with a plant process.
Mode setting means for setting one of the modes, and a terminal device and a plant process that configure a corresponding control loop so that when the mode is set, a predetermined electrical connection state is set for the set mode. A plant process control system, comprising: a state setting unit that sets an electrical connection state between the plant process state and a predetermined state. 3. The on-line mode according to claim 2, wherein the mode is an online mode in which signals are transmitted and received between a terminal device and a plant process forming a corresponding control loop, and both are electrically connected, and a corresponding control loop. A plant process control system, which comprises at least a bypass mode for stopping signal transmission and reception between a terminal device and a plant process, which constitutes the above, and electrically separating the two. 4. The processing device according to claim 1, wherein one processing device, which does not form a control loop, performs the same predetermined processing as other processing devices with respect to the dual system device among the terminal devices. A plant process control system characterized by performing.