JP2003015710A - Plant control system and process controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller capable of arbitrarily rearranging the input and output points of an operation end drive module corresponding to various auxiliary equipment without fixing them and to provide a plant controller in which the number of wiring is small. SOLUTION: A PDCM(operation end drive module) 200 belonging to a controller 100 for control is provided with a CPU 202, a non-volatile memory 203, and a serial I/F 204, and a serial signal is transmitted and received through a serial signal line 300 and an RTB 400 with the related equipment of a target auxiliary equipment. The memory 203 of the PDCM 200 is stored with a program for a projecting function or the like specific to the operation end, and when the controller 100 breaks down, the hold of an operation end 500 is executed by the CPU 202. Also, when an air source 510 is turned to be abnormal, the operation end is operated to a fail/safe side (full open/full close). The input and output point of the PDCM 200 are not fixed like hardware so that the extension or change of the functions can be arbitrarily executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plant control system, and more particularly to a process controller for directly controlling a plant, a connection system with the process equipment, and a processing system unique to an operating end.

[0002]

2. Description of the Related Art In recent years, in a large-scale plant control system, distributed control for controlling a plurality of process systems has become widespread. For example, a thermal power plant control system is equipped with a plurality of system controllers corresponding to the main engine, such as a boiler system, a turbine system, and a power generation system that are controlled by a master computer. Exhaust gas regulations have been realized.

Under each system controller, a plurality of process controllers for directly controlling the process equipment of the plant are provided. The process controller includes a single processor (CPU) and controls a plurality of devices by its arithmetic processing, which facilitates complicated control and optimization. In addition, it has the effect of making the controller compact and reducing the cost.

However, when a plurality of devices are operated by a single controller, if the CPU or input / output means of the device fails, it becomes impossible to control all the devices under the controller, and normally the plant operation is not possible. Make continuation difficult.

In order to solve this problem, the present applicant has proposed a system including a drive control module (DCM) described in Japanese Patent Publication No. 6-37845 (Cited example 1), and has been put to practical use for a long time. There is. Here, a DCM that corresponds to each device and is independent of each other is provided in a controller that directly controls a plurality of process devices (including operation terminals) by one CPU, and the DCM has analog and digital input / output units and a CPU. In case of abnormality, backup means is provided to hold the current control command value and allow manual adjustment. Also, a means for locking up to the current operation amount is added when the device has a failure.

By the way, in the conventional plant control system, due to restrictions such as vibration, temperature and humidity or noise at the site, a host controller and a process controller are installed in the control equipment room, and wiring is routed from there to the process side (site). Connected. In a thermal power plant, the distance between the control equipment room and the process is several tens to several hundreds of meters, and it is necessary to wire one wire for every operating end and instrumentation. It takes a lot of time to work. Therefore, the degree of freedom in changing the system is low and maintainability is poor. Therefore, as described in Japanese Patent Application Laid-Open No. 8-314505 (Cited example 2), there is a proposal to arrange a controller that directly controls the device near the operating end of the site.

[0007]

According to the method described in the reference 1, the device controller is provided with a DCM that corresponds to each device under its control in a one-to-one manner to improve the reliability and maintainability of the device controller. And is widely applied to power generation control systems. The improvements made by the applicant continued after that, for example, "Recent Thermal Power Generation Technology (Hitachi Review Vol.79 1997/3 pp29-
32) ”, the CPU in the DCM above
It is equipped with a non-volatile memory, and implements a programmable control module (PCM) that has a built-in protection function for plant auxiliary equipment that can operate even when the controller goes down, as well as the operating end interface.

The process equipment to be operated, in which the above-mentioned DCM and PCM have a one-to-one correspondence, is generally called an auxiliary machine, and is composed of operating ends such as valves and pumps and their peripheral equipment. Peripheral devices include instruments for controlling the control amount (process amount) and operation amount at the operating end,
Various types of instruments are included, such as limit switches that detect fully closed / opened, relays and switches that monitor for abnormalities in the drive source at the operating end, and so on. It may also include input means, such as signals required for manual adjustments, and other interlocking signals for other associated controls. Further, not only one operating end, but also a plurality of operating ends and peripheral devices thereof having a special interlocking relationship may be operated, such as a large valve and a small valve that interlock to control the flow rate.

However, as the control / protection function of the operating end is added to improve the controllability and reliability as described above, the number of input / output points of the controller is increased and the number of wires is further increased. Further, the processing function peculiar to each operating end is DC
The configuration of the input / output points of M is fixed individually to complicate the system design and change by changing the input / output points. Even if the system is changed, even if the type of terminal block or instrumentation is changed, if the number of input / output points is increased / decreased or rearranged, D
It cannot be realized easily because it involves the connection of the CM connector and the wiring work on site. Furthermore, the increase in the number of input / output points necessitates a change in the standard connector according to the board size of the drive control module. The increase in the connector size directly increases the size of the controller.

The method of reducing the wiring from the control equipment room to the site by arranging the controller near the operating end as in the second reference example is effective in terms of cost in recent systems. However, a new problem arises to cope with the site environment, such as providing an air-conditioning room to arrange the controller on site. If the controller is installed in the field without air conditioning, the failure rate will increase. For this reason, it is necessary to lower the clock to lower the computing capacity and to use expensive special parts, which is not practical.

An object of the present invention is to overcome the above-mentioned problems of the present situation, and to provide a process controller capable of arbitrarily recombining the input / output points of the drive control module without being fixed by the auxiliary machine and corresponding to various auxiliary machines. , To provide a plant control system using the same.

[0012]

In order to achieve the above object, the present invention is to install a plurality of process controllers for controlling a plurality of process equipment by connecting them through a network in a central control equipment room and attach them to the controller. A plant control system for controlling the process equipment by providing one or more operation end drive modules, connecting the module and the process equipment via transmission means,
The operation end drive module is provided with a serial communication means capable of bidirectional serial / parallel conversion, and a plurality of data such as a control command value of the operation end and a measured value of a process amount in the process equipment are transferred via a serial signal line. It is characterized in that it is configured to be able to input and output via.

Further, in the operating end drive module,
A non-volatile memory for storing a processing function specific to the target operation terminal in the form of software and a CPU for executing the software independently of the process controller are provided, and data necessary for the specific processing function is transferred to the serial signal line. It is characterized by inputting and outputting via.

The unique processing function is, for example, a protection (interlock) function for holding the target operation end or performing fail-safe operation. Alternatively, it is an interlocking control function described later.

Further, a serial communication means for performing bidirectional serial / parallel conversion and transmitting / receiving to / from the serial signal line is provided in the vicinity of the process equipment, and parallel connection of the data with the driving means or instrument of the process equipment. A remote terminal block module including input / output point terminals for input / output is provided.

The remote terminal block module is a conventional DCM without the functions of the CPU and memory, and is composed of hardware circuit means to improve the environment resistance in the field and close to the process equipment. Allows placement.

The remote terminal block module is divided into a module for inputting / outputting analog data to / from the process equipment and a module for inputting / outputting digital data (contact signal etc.), and outputs digital data via the serial signal line. It may be configured to be able to transmit and receive. In this case, the analog type terminal block module is provided with analog / digital conversion means and digital / analog conversion means.

Further, when the remote terminal block module is divided into a plurality according to the number of input / output points or the type of signal, each remote terminal block module is connected by multi-drop. This makes it possible to easily cope with an increase in the number of input / output points. Note that the upper limit of the number of input / output points is regulated by the communication amount of serial signals permitted from the control cycle of the plant.

Further, the operation end drive module and the remote terminal block module are constituted by a duplex serial line. As a result, the reliability of the system can be improved.

According to the present invention, when interlocking control is performed between a plurality of operating terminals to control a specific process amount, the processing procedure of the interlocking control is stored in the memory of the operating end drive module, and the CPU is stored. Calculates the individual control command value of each operation end and serially transmits it to each operation end through the serial signal line. An example of such a case is a two-valve interlocking control by two operation ends of a large flow valve and a small flow valve having different valve opening sizes. Alternatively, there is interlocking control of a plurality of water supply pumps having different supply capacities.

Further, a processing procedure for interlocking and protecting the operating end is stored in the memory, and the CPU receives data for monitoring abnormal operation of the operating end from each operating end through the serial signal line, and any operation is performed. When an abnormality is found in the operation of the end, all or part of the operation end is operated to the fail safe side.

A process controller according to the present invention is provided with a first CPU for performing control calculation of process equipment and a plurality of operating end drive modules connected to the CPU via a bus, and transmitting the module and the process equipment. In the one for controlling the process equipment by connecting via a means, the operation end drive module stores a non-volatile memory for rewriting the processing function specific to the target operation end in a rewritable manner and the software. A second CPU that executes independently of the first CPU is provided, and data necessary for control calculation of the first CPU and data necessary for unique processing of the second CPU are passed through the serial signal line. It is configured so that input and output can be performed.

According to the configuration of the present invention, the following actions and effects are realized. Since the operating-end drive module performs input / output with the process equipment by serial transmission, the configuration of the input / output points is not fixed for each target device, and the input / output points can be increased / decreased or rearranged freely by setting addresses. Therefore, it is possible to easily add a unique process according to the target device.

For example, the operation end drive module is provided with a software protection function, and the C of the process controller is provided.
When the PU goes down, the CPU of the operation end drive module can hold the target operation end as it is, or when the process device side has an abnormality, the operation end can be operated to the fail-safe side. Further, the interlocking control of a plurality of operating terminals can be processed collectively without being divided in hardware. Moreover, even if the processing unique to such process equipment is provided, it is not necessary to change the wiring in the control equipment room and the site.

The wiring between the operating end drive module and the target process equipment is connected via the terminal block module to
It can be connected with a book serial signal line. Also, when the number of input / output points of process equipment increases, it is sufficient to add terminal block modules and make multi-drop connections between them, which can provide a drastic solution to the enormous amount of wiring and wiring work in the past. it can.

As described above, according to the present invention, the standardization of the process controller and the peculiar interlock and interlocking process for each operating end can be easily provided, and the control performance and the reliability can be improved. In addition, the wiring between the control equipment room and the site can be greatly reduced, facilitating the construction, modification or maintenance of the plant system.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION First and second embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 shows the structure of a single-shaft combined cycle plant as an example of a power plant to which the present invention is applied. A combined cycle plant is a gas turbine consisting of a compressor, a turbine, and a combustor, an exhaust heat recovery boiler that recovers the exhaust heat of this gas turbine and supplies it to the steam turbine, a steam turbine that is directly connected to the gas turbine by a single shaft, and a generator. It consists of each main machine and auxiliary machines for its operation and measurement. The regulator valve shown in the figure is the operating end and is one of the accessories of the turbine.

FIG. 3 shows a layout of a power plant by the combined cycle plant of FIG. In the illustrated example, the four axes are set as one series (group), and two series configure one power plant. The layout space of this plant is about 300 m on a side. On the other hand, a plant control device for controlling each facility of the plant is usually installed in a room called a control equipment room near the central operation room. Conventionally, from this control equipment room to the operating end and measurement points of each auxiliary equipment on site, dozens of
Wiring is done one by one for a distance of several hundred meters. By the way, in the case of a 4-axis setler 2-series combined cycle, thousands of such wirings were required in the entire system.

FIG. 4 shows a schematic structure of a thermal power plant control system. The illustrated control system shows a configuration for one series of four axes in FIG. The main control room is equipped with an affiliated control panel, a large screen, an affiliated controller for the affiliated system, and a centralized maintenance tool. On the other hand, the control equipment room is connected to the central operation room via a series network, and an axis master computer and a control device for each main machine are arranged for each axis. The controller for direct control in the present invention is, for example, a gas turbine / steam turbine controller or a boiler controller.

FIG. 1 is a configuration of a plant control device showing a connection between a control controller and a control target auxiliary machine according to the first embodiment of the present invention.

The control controller 100 includes a CPU 10
1, a memory 102, and a PIO interface 104, which are connected by a controller internal bus 105. The CPU 101 controls an entire main process or a partial process of a target main machine, for example, a boiler. Normally, it has a transmission interface 103 and is connected to another controller for decentralized control.

Further, a plurality of drive control modules 200-1 to 200-n are provided from the PIO interface 104 via the PIO expansion bus 106.

Each drive control module 2
00 is a card in which a PIO interface 201, a CPU 202, a memory 203, and a serial interface 204 are mounted on a board. The memory 203 is a rewritable non-volatile memory, and has a protection function for each operating end, which has been conventionally configured by hardware, and software (program).
It is configured and stored by. The programmable drive control module 200 is hereinafter referred to as PDCM (Programmable Drive Control Module).

The PDCM 200 of this embodiment has a one-to-one correspondence with the auxiliary equipment on the site to be controlled, and connects the operating end and its peripheral equipment by one serial signal line 300. For this purpose, the serial interface 204 is provided, and the CP
The parallel data from U202 is converted into serial data, and the serial data from the serial signal line 300 is converted into parallel data.

As shown in FIG. 1, the serial signal line 300 is R
It inputs and outputs with the target auxiliary machine including a control end via TB (Remote Terminal Box) 400. As shown in FIG. 5, the serial signal line 300 has twisted pair cable connectors 30 at both ends of the twisted pair serial cable 301.
PD in the control equipment room, which consists of two and 303 connected
Connect the CM 200 and the RTB 400 on site with a connector.
Wiring work is easier and maintenance and inspection are easier than the conventional method in which crimp terminals are provided for each of the wires corresponding to the number of input / output points and screwed.

Further, the cable 301 and the connector 302,
Duplication of the serial line can be easily realized only by adding 303. If the routes for disposing the cables 301 are separated in the duplicated serial line, damage due to a fire or an earthquake can be stopped on one side, and the system can be easily restored.

A single serial twisted pair cable can transmit a plurality of P / S converted signals within a range of the serial communication capacity allowed from the control calculation cycle.
Further, because of the number of input / output points of the target auxiliary machine, when using a plurality of RTBs 400-1 and 400-2 as shown in FIG. 1, the RTBs are serially connected by multi-drop, so that the field and the control equipment room are connected. There is no need to increase the number of serial signal lines that connect between them. The configuration of the RTB 400 will be described later.

The target accessory in FIG. 1 is a pneumatic control valve 5
It is composed of a flow rate control valve whose operating end is 00 and its peripheral devices. The electro-pneumatic converter (E / P) 503 is the RTB400-1.
The solenoid nozzle that moves in proportion to the current value (E) of the manipulated variable output from the channel of the analog output unit (AO) adjusts the amount of air supplied from the air pressure source 510 to obtain the manipulated variable (E). Convert to the corresponding air pressure (P). The air pressure / valve position converter (P / P) 502 is supplied from the air pressure source 510 and adjusts the opening degree of the valve 500 to a valve position corresponding to the air pressure (P). P / P502
The valve opening degree meter 507 provided at the input side inputs the valve opening degree at the operating end to the channel of the analog input section (AI). Further, the process flow rate controlled at the operating end is measured by the flow meter 501 and input to the AI channel.

The limit switch 506 is provided on the operating end 500.
Detection of full open or full close of RTB40
0-2 digital input (DI) channels, and the air pressure monitoring pressures SW 508 and 509 are connected to the air pressure source 5
The air supply from 10 is monitored, respectively, and when the air pressure drops abnormally (air loss), an air pressure abnormal signal is input to the DI channel or. The interlock signal output from the channel of the digital output section (DO) of the RTB 400-2 operates the forced operation solenoid valve 504 to fully open or fully close the operating end 500. Further, the hold signal output from the channel operates the opening degree holding solenoid valve 505 to hold the opening degree of the operating end 500 at the present state.

FIG. 6 shows the structure of the RTB that inputs and outputs analog and digital signals. RTB of this embodiment
Excludes the functions realized by the CPU and memory from the conventional drive control module described in the cited examples, and configures the interface function with the target device by a hardware circuit and arranges it near the target device. There is.

The RTB 400 is an address of a signal handled by the serial I / F 401 and the RTB 400 that converts (P⇔S) the data transmitted / received via the serial signal line 300 from serial (S) to parallel (P) or vice versa. It has an address setter 402 for setting a clock signal and an oscillator circuit 403 for outputting a clock signal for the operation of the RTB 400.

The related auxiliary equipment of the target auxiliary equipment is connected through the terminal block 200, and the DI signal thereof is fetched by changing the signal level through the level changer 407. Further, the AI signal is taken in through a secondary converter and converted into digital data by an MPX (multiplexer) 406 and an A / D converter 405. These input data are serial I / F
At 401, it is converted into a serial signal in order, an address is given at this time, and it is sent to the serial signal line 300 at a predetermined timing.

On the other hand, the serial signal received by the serial I / F 401 fetches only the address addressed to itself when there are a plurality of serially connected RTBs. D such as interlock
The O signal is output to the corresponding operating device via the level changer 412 and the terminal block 420 after being latched in the corresponding address part of the latch circuit 411. Operating end command AO
The signal is converted into analog data via the D / A converter 413 and the DE-MPX 414, amplified by the amplifier 415, and output. In addition, when the input and output of the analog signal and the digital signal are shared by different RTBs as shown in FIG. 1, only one function is required.

The above operation of the RTB 400 is controlled by the input control circuit 404 and the output control circuit 410, respectively. The control circuits 404 and 410 are composed of a hard circuit such as an LSI, and advance the operation of each circuit in a predetermined sequence while stepping with the clock of the transmitting circuit 403. The operation of the RTB and the controller for control may be performed asynchronously, but all Rs connected in serial are
The series of input / output cycles of TB is the controller 100 for control.
Is restricted by the control cycle of. In addition, since the other devices and circuits of the RTB 400 are also configured by hardware, malfunctions are less likely to occur even in a field environment where there are high temperatures, dust, noise, and the like.

As described above, the RTB of this embodiment does not have a CPU or a memory and has improved environmental resistance only by hardware, so that the RTB can be installed near the target device on the site without using an air conditioning room or the like. Also, you can easily multi-drop connection with one twisted pair serial cable and increase the number of input / output points as needed.
It is easy to build and change the system or change the equipment inside the RTB.

Next, the operation of the plant controller according to the first embodiment will be described. First, a transmission / reception process of a serial signal will be described. FIG. 7 shows a format of a serial signal and a transmission / reception processing flow thereof. As shown in (a), the serial signal has a start flag, data, an address, an end flag, and the like, followed by inverted data obtained by inverting them. PDCM200 and RTB400
In the meantime, the dedicated LSI used by both of the serial I / 204 and 401 performs processing while looping back and forth transmission and reception.

As shown in FIG. 6B, the PDCM 200
When the data transmission / reception process is started (s101), a transmission serial signal is created (s102) and transmitted to the RTB 400 side (s103). When the RTB 400 receives the serial signal (s104), the RTB 400 performs a data reception process based on the data rationality check (s105). The rationality check performs a reverse data comparison process, a reverse flag check, and a time-out judgment (s1051). As a result, RT
If the reception from B is normal, the data is passed to the corresponding address (s1052), and if abnormal, the data is discarded (s1053). Then, from RTB400 side to PDCM
The return data transmission process is automatically started to the 200 side (s106). The RTB 400 creates a transmission serial signal (s107) and transmits it to the PDCM200 side (s1).
08). When the PDCM 200 receives the return signal (s109), the PDCM 200 performs the data reception process by the rationality check similar to step s105, and when the data is normally received, the data is taken into the corresponding address (s110).

The address of the serial signal will be described with reference to FIG. When the PDCM 200 and the RTB 400 are serially connected as in (a), the address of the input / output data of the RTB 400 is set, for example, as in the table of (b). That is, from PDCM200 to RTB400-
The addresses of output 1 and output 2 sent to 1 are RTB
The output data addresses of (1) are 1 and 2. For example,
The output data address 1 is the control command value of the operating end. The addresses 3 and 4 shown in the figure are unused and are missing numbers. On the other hand, the addresses of the input 1 and the input 2 transmitted from the RTB 400-1 to the PDCM 200 are the input data addresses 1 and 2 of the RTB (1). For example, the input data address 1 is a measured value of the process amount.

Addresses according to the above correspondence table are given to the serial signals and transmitted in the order of addresses. Usually A
Since the I and AO analog signals are digitized and represented by a plurality of bits, one signal is transmitted per frame. However, digital signals of DI and DO often transmit a plurality of addresses collectively in one frame.

FIG. 9 shows a processing flow of the plant protection operation performed by PDCM. This processing program is PDCM2
00 is stored in the memory 203 and is executed by the CPU 202. When normal automatic control is being performed, C
The PU 202 processes according to the following procedure for each control cycle.

First, referring to the normal signal of the CPU 101,
It is checked whether the controller 100 is operating normally (s201). If it is normal, the RTB normal diagnosis is performed on the valve opening signal by referring to the measured value of the valve opening meter 507 (s202). The RTB normal diagnosis is a rationality judgment check at the time of the reception processing. If the valve opening meter signal is normal, it is checked whether it is operating according to the command value (s203).
If it is operating normally, the measured value of the limit switch 506 of the valve opening at the operating end is referred to, and the RTB normal diagnosis (s
If the result of 204) is normal, it is checked whether the value of the opening LS signal is on the normal side (1/0) (s205). If it is normal, the measured values of the air pressure monitoring pressures SW508 and 509 are referred to. If the result of the RTB normal diagnosis (s206) is normal, check whether there is any abnormality in the air pressure (s
207). If there is no abnormality, the processing of the cycle is ended.

On the other hand, if it is determined that there is an abnormality in s201, it is considered that the controller is abnormal and a hold signal is output (s20
8), the opening degree holding solenoid valve 505 holds the opening degree of the operating end 500 at the current state, and the manual mode is enabled (s21).
1). When the result of RTB normal diagnosis by s202 is abnormal (?), The interlock signal is output because of RTB abnormality (s209), and the operation end 500 is operated in the fail safe direction (fully opened or fully opened) by the forced operation solenoid valve 504. Close). Furthermore, s203, s205 and s
If it is abnormal in any of 207, it is regarded as an operation end abnormality and an interlock signal is output (s210), and in s212, it is operated in the fail-safe direction (fully open or fully closed) to prevent the occurrence or spread of a plant accident. To do.

In this way, when the control controller 100 is abnormal, the CPU 202 of the PDCM 200 can independently perform control calculation and interlock the operating end. In the above process, serial I /
It may be performed by a dedicated LSI of F204. Also,
The protection circuit by the software stored in the memory 203 is installed in the CR of the maintenance tool (workstation) of FIG.
It is also possible to visualize T and monitor its operating state.

As described above, according to the first embodiment, since the input / output points of the PDCM are not fixed by the serial connection, the standard PDCM is changed to correspond to the unique processing such as interlock and hold which is different for each operation end. It is possible to freely change the composition used and easily design any system. Further, since multiple RTBs can be serially connected by multi-drop, it is possible to flexibly cope with diversification of the number of input / output points of the target auxiliary machine, the operation end, the type of instrumentation, and the like. As a matter of course, since the PDCM and the target auxiliary device in the field can be connected by one serial signal line in principle, the field wiring can be significantly reduced.

Of course, the number of serial signal lines to the target accessory is not limited to one. As described above, the serial signal line may be duplicated. Further, in the plant control system, in order to avoid the loss of process data or the like that has a significant effect on the whole, the corresponding measurement point is also configured in a dual configuration.

FIG. 10 shows another embodiment in which the PDCM and the target accessory are connected by a plurality of serial signal lines. The difference from FIG. 1 is that the dual process flowmeter 50.
Each of the measured values (AI) of 1a and 501b is transferred to a dedicated RTB 400-1a, 1b and DPCM 200-1a,
The point is that the input is made to the control controller 100 via 1b.

In the present embodiment, the input / output of the target auxiliary machine is not collectively performed in one PDCM, and the P that exclusively inputs / outputs a specific signal is used.
The DCM is separately placed and connected to the dedicated serial signal line via the RTB. This also maintains the reliability of the system while significantly reducing the number of conventional wiring. In this case, the protection function unique to PDCM is one DPCM.
Since the input and output points are not fixed, it is possible to rearrange flexibly to add or change functions or change the model of auxiliary equipment.

As described above, by duplicating the serial line, even if an abnormality such as disconnection occurs in one system (main system), the function can be taken over by the remaining one system. Furthermore, in case of a disaster, if the duplicated serial line is routed through another route in the power plant, the reliability of the system can be further improved.
According to the present embodiment, the number of wirings is greatly reduced by serial communication and the input / output points are not fixed, so that such a redundant configuration can be easily realized.

Next, a second embodiment of the present invention will be described. In the above-described first embodiment, the PDCM has a one-to-one correspondence with the operating end of the target auxiliary machine, and the control controller 100
Control command is output to the corresponding operation terminal via PDCM. However, although it is originally one control function, it may be shared among a plurality of operation terminals and processed. For example,
In order to control the flow rate of a wide range with good accuracy in all ranges, a large size valve and a small size valve are placed side by side,
It is necessary to make adjustments while linking the two. Incidentally, there are cases in which three valves are operated in conjunction with each other at coal-fired power plants.

Conventionally, in such interlocking control, an individual command for each operating end is calculated by a control controller and is output through each drive control module. In other words, although the configuration is functionally one piece, the hardware is divided and processed. In the present embodiment, such functionally grouped interlocking control is executed by one PDCM as follows.

FIG. 11 is a schematic diagram of a plant control device for performing two-valve interlocking control. The basic configuration of the control device is shown in Fig. 1.
However, the target operation ends of the PDCM 200 are the large flow valve 600 and the small flow valve 700. Although peripheral devices of each valve are not shown, they are almost the same as those in FIG.

Upon receiving the total flow rate control command from the CPU 100, the PDCM 200 executes the two-valve interlocking control program and outputs the large flow rate valve 600 and the small flow rate valve 700 opening commands, and the serial signal line 300 and the RTB 400-1.
Control via via. RTB400-1 (AI /
O) and 400-2 (DI / O) are large flow valves 600 and their peripheral devices, and RTB400-3 (AI / O) and 400.
-4 (DI / O) is connected to the small flow valve 700 and its peripheral devices, respectively.

The PDCM 200 executes the control operation of the interlock logic together with the above-mentioned two-valve interlocking control,
Protect the plant. The two-valve interlocking control procedure and the interlock logic are stored in the memory 203 as a program.

FIG. 12 shows an example of a characteristic diagram of the two-valve interlocking control. When the flow rate is 50% or less, only the valve opening degree of the small flow valve 700 is controlled in proportion to the flow rate, and the large flow valve 600 is fully closed during this period. On the other hand, when the flow rate is 50% or more, the small flow valve 7
00 is held fully open, and the valve opening degree of the large flow valve 600 is controlled in proportion to the flow rate. The PDCM 200 of this example is configured such that the large flow valve 60 is operated according to a control command from the controller 100.
0 and the valve opening degree of each of the small flow valves 700 are calculated, and commanded to each by serial transmission. As a result, the flow rate of 0
The range of -100% can be controlled accurately.

FIG. 13 shows a processing flow of the interlock logic. During normal automatic control, first, it is determined whether the controller 100 is normal by the controller normal signal.
When it is recognized that the controller is abnormal, a command to hold the opening of the operating end is output and the mode is switched to the manual mode (s308, s).
312). On the other hand, when the controller 100 is operating normally, the measurement signal from each operation end is referred to after the RTB normal diagnosis (s300), and the determination by the following interlock logic is performed.

First, the operation check on the small flow valve 700 side is performed. Referring to the opening meter signal of the small flow valve 700, check whether the small flow valve 700 is operating according to the command value (s
302). If normal, the limit switch signal of the small flow valve 700 is referred to check whether the small flow valve 700 is operating normally according to the interlocking relationship (s303). If the limit switch signal is normal, the air source pressure SW signal is referred to check whether the air pressure source is normal (s30).
4). Small flow valve 7 in any of the above s302 to s304
When the abnormality of 00 is detected (s310), the electromagnetic valve output of the large flow valve / small flow valve fully closed (or fully open) is issued, and the fail-safe operation is performed (s313). If each judgment on the small flow valve 700 side is normal, then on the large flow valve 600 side, the small flow valve 70 is processed by steps s305 to s307.
Similar to the 0 side, the operation check is performed, and if an abnormality is detected, the fail safe operation is performed. However, only one of the interlocking control operation ends may be fail-safe operated.

The interlock processing procedure described above is stored in the memory 203, but it can be converted into a sequence diagram or a logic circuit diagram by the maintenance tool of FIG. 4 and its operating state can be monitored by the CRT.

As described above, in the present embodiment, each control command for a plurality of flow valves having the same control function and interlocking relationship is set to 1
Calculated by the program stored in two PDCMs, P
Each valve is interlocked and controlled by serial connection from DCM. Also, the interlock of each of these valves is
Processes in conjunction with the logic stored in. This allows
Originally, a set of functions can be easily configured without dividing the hardware, so that the control performance of the system can be improved and the fail-safe design of the system can be facilitated.

In the above embodiment, the interlocking control of the large flow valve and the small flow valve is shown, but the present invention is not limited to this. For example, in thermal power plants, in addition to this,
Large auxiliary equipment such as a recirculation pump, a control oil pump, a fuel pump, a heavy oil pump, etc., perform similar interlocking control with peripheral equipment. The present invention can also be applied to such interlocking control, and can achieve the same effects as in the case of the embodiment.

In the range related to the interlocking control as in this example, the number of input / output points including the protection function is often 20 or more. However, since this PDCM enables a large number of input / output points by serial connection, it is not necessary to use a special connector as in the conventional case, the system design is easy and the maintainability can be improved.

[0072]

According to the present invention, the serial IF is provided in the operation end drive module that is attached to the control controller and performs input / output with the target auxiliary machine of the plant, and the target auxiliary machine and one serial signal line are provided. Since they are connected by the system, the field wiring can be significantly reduced, and the operating end drive module can be standardized. This has the effect of facilitating system construction and reducing its cost.

In addition, when the CPU for operating independently of the control controller is mounted on the operating end drive module to execute the processing unique to the operating end such as the interlock of the target auxiliary machine, the above serial connection is used. Operating-end drive module Since multiple I / O points are not fixed by hardware, it is possible to easily add or change functions by freely rearranging I / O points, improving system controllability and reliability. There is an effect that can be improved.

Furthermore, when a plurality of operating ends are in a linked relationship that originally achieves one function, these operating ends can be controlled through one operating end drive module without being divided by hardware, so that the control performance of the system is improved. Facilitates improved and fail-safe design.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a plant control device of the present invention.

FIG. 2 is a schematic diagram showing an example of a plant to which the present invention is applied.

FIG. 3 is an explanatory diagram showing a layout of the plant of FIG.

FIG. 4 is a block diagram of a supervisory control system that performs overall supervisory control of the plant of FIG.

FIG. 5 is an explanatory diagram showing an example of serial signal lines and their connections.

FIG. 6 is a configuration diagram showing an embodiment of RTB.

FIG. 7 is an explanatory diagram showing a serial signal between PDCM and RTB and a transmission / reception process thereof.

FIG. 8 is an explanatory diagram of input / output data and its setting address on the RTB side.

FIG. 9 is a flowchart showing an example of an interlock process by PDCM.

FIG. 10 is a configuration diagram of a plant control device which is a modification of FIG. 1 and in which serial connections are multiplexed.

FIG. 11 is another embodiment of the plant control device of the present invention,
The block diagram which shows interlocking control.

FIG. 12 is an explanatory diagram showing sharing of flow rate by interlocking control of a large flow valve and a small flow valve.

13 is a flowchart showing interlock by PDCM in the interlocking control of FIG.

[Explanation of symbols]

100 ... Controller for control, 101 ... CPU, 102
... memory, 103 ... transmission interface, 104 ... PI
/ O interface, 105 ... Internal bus, 200 ... PD
CM (Programmable Drive Cnotrol Module), 201
... PI / O interface, 202 ... CPU, 203 ...
Nonvolatile memory, 204 ... Serial I / F, 300 ... Serial signal line, 400 ... RTB (Remote Terminal Bo)
x), 401 ... Serial I / F, 402 ... Address setter, 403 ... Sending circuit, 404 ... Input control circuit, 405
... A / D converter, 406 ... MPX, 407 ... Level changer, 408 ... Secondary converter, 410 ... Output control circuit,
411 ... Latch circuit, 412 ... Level changer, 41
3 ... D / A converter, 414 ... DE-MPX, 415 ... Amplifier circuit, 420 ... Terminal block, 500 ... Pneumatic control valve (operating end), 501 ... Process flow meter, 502 ... P / P converter, 503 … E / P converter, 504… Forced operation solenoid valve,
505 ... Opening degree holding solenoid valve, 506 ... Opening degree monitoring limit S
W, 507 ... Valve opening meter, 508, 509 ... Air pressure monitoring pressure SW, 510 ... Air source, 600 ... Large flow valve, 700 ...
Small flow valve.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shigeki Adachi             5-2-1 Omika-cho, Hitachi City, Ibaraki Prefecture             Ceremony company Hitachi Ltd. Omika factory (72) Inventor Katsuhito Shimizu             5-2-1 Omika-cho, Hitachi City, Ibaraki Prefecture             Ceremony company Hitachi Ltd. Omika factory F-term (reference) 5H220 AA02 BB09 CC09 CX05 EE09                       HH01 JJ12 JJ26 JJ28 KK03                       MM06

Claims (14)

[Claims] 1. A plurality of process controllers for controlling a plurality of process equipments are connected by a network and installed in a central control equipment room, and one or more operation end drive modules are attached to the controller, and the module and the module are provided. In a plant control system for controlling process equipment by connecting process equipment via a transmission means, the operation end drive module is provided with serial communication means capable of bidirectional serial / parallel conversion, and operation in the process equipment is performed. A plant control system characterized in that a plurality of data such as end control command values and process amount measurement values are configured to be input / output via a serial signal line. 2. The operation-end drive module according to claim 1, wherein the operation-end drive module has a non-volatile memory that stores a processing function specific to a target operation end in software, and a CPU that executes the software independently of the process controller. And a data input / output for the data necessary for the unique processing function via the serial signal line. 3. The plant control system according to claim 2, wherein the unique processing function is a protection function and holds and / or fails-safely operates a target operation end. 4. The serial communication unit according to claim 1, 2 or 3 for performing bidirectional serial / parallel conversion and transmitting / receiving to / from the serial signal line, in the vicinity of the process device, a driving unit of the process device, A plant control system comprising a remote terminal block module including an input / output point terminal for inputting / outputting the data by connecting in parallel with an instrument. 5. The remote terminal block module according to claim 4, wherein the remote terminal module is divided into one for inputting / outputting analog data to / from the process equipment and one for inputting / outputting digital data (contact signal etc.), and the serial signal. A plant control system characterized in that digital data can be transmitted and received via a line. 6. The plant control system according to claim 4, wherein the remote terminal block module does not have a CPU or a memory, and is configured by hardware circuit means. 7. The remote terminal block module according to claim 4, wherein when the remote terminal block module is divided into a plurality according to the number of input / output points or the type of signal, the remote terminal block modules are connected by multi-drop. A plant control system characterized by the above. 8. The plant control system according to claim 4, 5, 6 or 7, wherein the operating end drive module and the remote terminal block module are configured by a duplex serial line. 9. A computer connected to a central control equipment room via a network and a process controller for controlling a plurality of process equipments of a plant are installed, and a plurality of operation end drive modules are attached to the controller, and the module is provided. In the plant control system for controlling the process equipment by connecting the process equipment via a transmission means, the operation end drive module, a non-volatile memory for storing a processing function specific to the target operation end by software, A CPU that executes the software independently of the process controller and a serial communication unit that can perform bidirectional serial / parallel conversion are provided, and interlock control is performed between a plurality of operating terminals to control a specific process amount. In this case, the processing procedure of the interlocking control is stored in the memory, and Plant control system characterized by calculating the individual control command value for the operating end by a CPU, a configured to transmit serially to each operating end through the serial signal line. 10. The processing procedure according to claim 9, wherein the memory stores a processing procedure for interlocking protection of the operating end, and the CPU receives data for monitoring abnormal operation of the operating end from each operating end through the serial signal line. , A plant control system characterized in that, when an abnormality is found in the operation of any one of the operating ends, all or part of the operating end is operated to the fail-safe side. 11. The CP according to claim 9 or 10, wherein a processing procedure of the interlocking control and / or the interlocking protection stored in the memory is visualized.
A plant control system characterized in that a monitoring means for displaying a processing operation by U is connected to the network in the central control equipment room and is controlled by the computer. 12. The plant control system according to claim 9, 10 or 11, wherein the plurality of operating ends for performing the interlocking control are a plurality of flow valves having different valve opening sizes or a plurality of flow pumps having different supply capacities. . 13. A central control equipment room is provided with a first CPU for performing control calculation of a plurality of process equipment, and a plurality of operation end drive modules connected to the CPU via a bus, and the module and the process equipment. In a process controller for controlling the process equipment by connecting via a transmission means, in the operation end drive module, a non-volatile memory for storing rewritable by creating a processing function specific to the target operation end by software, A second CPU that executes the software independently of the first CPU is provided, and the data necessary for the control calculation of the first CPU and the second CP are provided.
A process controller characterized in that data necessary for unique processing of U can be input and output via the serial signal line. 14. The process controller according to claim 13, wherein the unique processing function is an interlock of a target operation end and / or an interlocking control between a plurality of operation ends.