JP3825363B2 - Plant control system and process controller - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plant control system, and more particularly to a process controller that directly controls a plant, a connection method between the process equipment, and a processing method unique to an operation end.
[0002]
[Prior art]
In recent years, distributed control for controlling a plurality of process systems has become widespread in control systems for large-scale plants. For example, a thermal power plant control system is equipped with a plurality of system controllers that are generally compatible with the main engine, such as a boiler system, a turbine system, and a power generation system that are supervised by a master computer. Realizes exhaust gas regulations.
[0003]
A plurality of process controllers that directly control the process equipment of the plant are provided under each system controller. Since the process controller includes a single processor (CPU) and controls a plurality of devices through its arithmetic processing, complicated control and optimization are facilitated. It also has the effect of making the controller compact and reducing costs.
[0004]
However, when multiple devices are operated by a single controller, if the CPU or input / output means fails, it becomes impossible to control all the devices under the controller, and it is usually difficult to continue plant operation. To.
[0005]
In order to solve this problem, the present applicant has proposed a method including a drive control module (DCM) described in Japanese Patent Publication No. 6-37845 (Cited Example 1) and has been put into practical use. Here, a controller that directly controls a plurality of process devices (including operation ends) by a single CPU is provided with DCMs corresponding to the respective devices and independent from each other. Back-up means is provided that enables manual adjustment by holding the current control command value in the event of an abnormality. In addition, a means for locking up to the current operation amount when there is a failure on the device side is also added.
[0006]
By the way, in the conventional plant control system, due to restrictions on site vibration, temperature / humidity, noise, etc., a host controller and process controller are installed in the control equipment room, and the wiring is drawn from there to connect to the process side (site). Yes. In thermal power plants, the distance between the control equipment room and the process is several tens to several hundreds of meters, and it is necessary to wire each operation end and instrumentation one by one. It takes a lot of time to work. For this reason, the degree of freedom of system change is low and the maintainability is also poor. For this reason, as described in Japanese Patent Laid-Open No. 8-314505 (Cited Example 2), there is a proposal to arrange a controller that directly controls the equipment near the operation end in the field.
[0007]
[Problems to be solved by the invention]
The method described in Cited Example 1 improves the reliability and maintainability of the device controller by providing the device controller with one-to-one DCM for each device under its control, and is widely applied to power generation control systems. ing. Improvements by the applicant continued, and as described in, for example, “Recent Thermal Power Generation Technology (Hitachi Review Vol.79 1997/3 pp29-32)”, the above DCM is equipped with a CPU and non-volatile memory. In addition to the operation end interface, a programmable control module (PCM) having a built-in protection function for plant auxiliary equipment that can operate even when the controller is down is realized.
[0008]
The process device to be operated corresponding to the above-described DCM or PCM on a one-to-one basis is generally called an auxiliary machine, and includes an operation end such as a valve or a pump and its peripheral devices. Peripheral devices include various control instruments (process quantity), control instruments for operation quantity, limit switches for detecting fully closed / open, etc., relays and switches for monitoring abnormalities such as drive sources for operating terminals, etc. Is included. In addition, input means such as a signal necessary for manual adjustment and an interlock signal of another related operation end may be included. Furthermore, there are cases where not only one operation end but a plurality of operation ends and its peripheral devices that are in a special interlocking relationship are targeted for operation, such as a large valve and a small valve that control the flow rate in conjunction with each other.
[0009]
However, as described above, in order to improve controllability and reliability, as the control / protection function of the operation end is added, the number of input / output points of the controller increases, and the number of wires increases. In addition, the processing function unique to each operation end fixes the configuration of the input / output points of the DCMs individually, and complicates the design and change of the system by rearranging the input / output points. In addition, even if the type of the terminal block or instrumentation is changed, the system change is easily realized because it involves the connection of the DCM connector and the on-site wiring work if the input / output points are increased or decreased or recombined. Can not. 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. An increase in connector size directly increases the size of the controller.
[0010]
Note that the method of reducing the wiring from the control device room to the site by arranging the controller near the operation end as in the cited example 2 is also effective from the viewpoint of cost in a recent system. However, a new problem arises in order to cope with the on-site environment, such as providing an air-conditioning room for arranging the controller on-site. If the controller is installed on site without air conditioning, the failure rate increases. For this reason, it is necessary to lower the clock to lower the computing capacity or use expensive special parts, which cannot be put into practical use.
[0011]
An object of the present invention is to overcome the above-described problems of the present situation, and to provide a process controller that can be arbitrarily rearranged in accordance with various auxiliary machines, without the input / output points of the drive control module being fixed by the auxiliary machines. It is to provide a plant control system used.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a plurality of process controllers for controlling a plurality of process devices are connected by a network and installed in a central control device room, and one or more operation end drive modules are attached to the controller. In a plant control system for controlling the process equipment by connecting the module and the process equipment via a transmission means, the operation end drive module is provided with serial communication means capable of bidirectional serial / parallel conversion. A plurality of data such as a control command value at the operation end and a measured value of the process amount in the process device can be input / output via a serial signal line.
[0013]
Further, the operation end drive module is provided with a non-volatile memory for storing processing functions unique to the target operation end in software, and a CPU for executing the software independently of the process controller, and the unique processing functions The data necessary for the input / output is input / output via the serial signal line.
[0014]
The unique processing function is, for example, a protection (interlock) function for holding a target operation end or performing a fail-safe operation. Or it is the interlocking control function etc. which are mentioned later.
[0015]
Also, in the vicinity of the process equipment, serial communication means that performs bidirectional serial / parallel conversion and transmission / reception with the serial signal line, and parallel connection with the drive means and instruments of the process equipment are used to input / output the data. A remote terminal block module including an input / output point terminal is provided.
[0016]
The remote terminal block module is a conventional DCM excluding functions such as CPU and memory, and is composed of hardware circuit means, improving environmental resistance in the field and allowing it to be placed near process equipment I have to.
[0017]
The remote terminal block module is divided into one that inputs / outputs analog data to / from the process equipment and one that inputs / outputs digital data (contact signal, etc.) so that digital data can be transmitted / received via the serial signal line. You may comprise. In this case, the analog type terminal block module is provided with analog / digital conversion means and digital / analog conversion means.
[0018]
Further, when the remote terminal block module is divided into a plurality of parts depending on the number of input / output points or signal types, the remote terminal block modules are connected in a multi-drop manner. Thereby, it is 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 that is allowed from the control cycle of the plant.
[0019]
Further, the operation end drive module and the remote terminal block module are configured by a duplex serial line. Thereby, the reliability of the system can be improved.
[0020]
In the present invention, when interlock control is performed between a plurality of operation ends to control a specific process amount, the processing procedure of the interlock control is stored in the memory of the operation end drive module, and each operation is performed by the CPU. An individual control command value at the end is calculated and serially transmitted to each operation end through the serial signal line. In such an example, there 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 interlock control of a plurality of feed pumps having different supply capacities.
[0021]
In addition, a processing procedure for interlocking protection of the operation end is stored in the memory, and the CPU receives data for monitoring an abnormal operation at the operation end from each operation end through the serial signal line. When an abnormality is recognized, all or part of the operation end is moved to the fail-safe side.
[0022]
A process controller according to the present invention includes a first CPU that performs a control operation of a process device, and a plurality of operation end drive modules connected to the CPU via a bus, and the module and the process device are connected via a transmission unit. Connected to control the process equipment, in the operation end drive module, a non-volatile memory for storing a unique processing function of the target operation end in software and rewritable, and the software in the first CPU A second CPU that is executed independently of the first CPU, and inputs data necessary for the control calculation of the first CPU and data necessary for processing unique to the second CPU via the serial signal line. It is configured to be able to output.
[0023]
According to the configuration of the present invention, the following operations and effects are realized. Since the operation end drive module performs input / output to / from the process equipment through serial transmission, the configuration of the input / output points is not fixed for each target device, and the increase / decrease and recombination of the input / output points can be freely performed by setting the address. Therefore, a unique process according to the target device can be easily added.
[0024]
For example, if a software protection function is provided in the operation end drive module and the process controller CPU goes down, the operation end drive module CPU keeps the current operation end in the current state, or if there is an abnormality on the process equipment side The end can be operated to the fail-safe side. Further, the interlocking control of a plurality of operation ends can be processed together without being divided into hardware. Moreover, even if such a process device is provided with unique processing, it is not necessary to change the wiring between the control device room and the site.
[0025]
Wiring between the operation end drive module and the target process device can be connected through a terminal block module with a single serial signal line. In addition, when the number of input / output points of process equipment increases, it is only necessary to add terminal block modules and make multidrop connections between them, which can provide a drastic solution to the conventional huge amount of wiring and wiring work. it can.
[0026]
As described above, according to the present invention, the standardization of the process controller and the interlock and the interlocking process unique to each operation end can be easily provided, and the control performance and reliability can be improved. In addition, since the wiring between the control equipment room and the site can be greatly reduced, the construction, change or maintenance of the plant system is facilitated.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, first and second embodiments of the present invention will be described in detail with reference to the drawings.
[0028]
FIG. 2 shows a configuration of a uniaxial combined cycle plant as an example of a power plant to which the present invention is applied. A combined cycle plant includes a compressor, a turbine, a gas turbine including a combustor, an exhaust heat recovery boiler that recovers exhaust heat of the gas turbine and supplies the exhaust gas to the steam turbine, a steam turbine that is directly connected to the gas turbine and rotates, and a generator The main machine and auxiliary equipment for its operation and measurement. The illustrated control valve is an operation end and is one of the auxiliary machines of the turbine.
[0029]
FIG. 3 shows the layout of the power plant by the combined cycle plant of FIG. In the illustrated example, four powers are grouped into one series (group), and one power plant is configured with two series. The arrangement space of this plant is about 300 m on a side. On the other hand, a plant control apparatus that controls each plant facility is usually installed in a room called a control equipment room close to the central operation room. Conventionally, a distance of several tens to several hundreds of meters is wired one by one from the control device room to the operation end and measurement point of each auxiliary machine on site. By the way, in the case of a combined cycle of a 4-axis settler 2 series, the entire system required several thousand wires like this.
[0030]
FIG. 4 shows a schematic configuration of the thermal power plant control system. The illustrated control system shows the configuration for one series of four axes in FIG. In the central operation room, a series control panel and a large screen, a series common control device, a centralized maintenance tool, etc. are arranged. On the other hand, the control equipment room is connected to the central operation room via a series network, and an axis master computer, a control device for each main machine, and the like are arranged for each axis. The controller for direct control in the present invention is, for example, a gas turbine / steam turbine control device or a boiler control device.
[0031]
FIG. 1 is a configuration of a plant control apparatus showing a connection between a controller for control according to a first embodiment of the present invention and an auxiliary device to be controlled.
[0032]
The control controller 100 includes a CPU 101, a memory 102, and a PIO interface 104, and is connected via a controller internal bus 105. The CPU 101 controls an entire process or a partial process of a target main machine, for example, a boiler. Usually, it has a transmission interface 103 and is connected to other control controllers for distributed control.
[0033]
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.
[0034]
Each drive control module 200 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. A memory 203 is a rewritable non-volatile memory that stores and protects a protection function for each operation end, which is conventionally configured by hardware, by software (program). In this manner, the programmable drive control module 200 is hereinafter referred to as a PCM (Programmable Drive Control Module).
[0035]
The PCDCM 200 of this embodiment has a one-to-one correspondence with the on-site auxiliary equipment to be controlled, and connects the operation end and its peripheral devices through a single serial signal line 300. For this purpose, a serial interface 204 is provided, which converts parallel data from the CPU 202 into serial data, and converts serial data from the serial signal line 300 into parallel data.
[0036]
As shown in FIG. 1, the serial signal line 300 inputs and outputs with a target auxiliary machine including an operation end via an RTB (Remote Terminal Box) 400. As shown in FIG. 5, the serial signal line 300 includes twisted pair cable connectors 302 and 303 connected to both ends of a twisted pair serial cable 301, and connects the PCM 200 in the control device room and the RTB 400 in the field by connectors. Compared with the conventional method in which crimp terminals are provided for each of the wires corresponding to the number of input / output points and screwed, wiring work is simple and maintenance inspection is facilitated.
[0037]
In addition, duplication of the serial line can be realized simply by adding the cable 301 and the connectors 302 and 303. If the arrangement route of the cable 301 is made separate with this duplicated serial line, damage due to a fire or an earthquake can be stopped in one system and the system can be easily restored.
[0038]
The serial twisted pair cable is a single cable and can transmit a plurality of P / S converted signals within the range of serial communication capacity allowed from the control calculation cycle. Also, due to the necessity 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 multidrop, so the field and the control equipment room There is no need to increase the number of serial signal lines connected between them. The configuration of the RTB 400 will be described later.
[0039]
The target auxiliary machine in FIG. 1 includes a flow control valve having a pneumatic control valve 500 as an operation end and its peripheral devices. The electropneumatic converter (E / P) 503 is operated by a solenoid nozzle that moves in proportion to the current value (E) of the manipulated variable output from the channel (1) of the analog output unit (AO) of the RTB 400-1. The amount of air supplied from the source 510 is adjusted and converted to air pressure (P) corresponding to the manipulated variable (E). 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). A valve opening degree meter 507 provided in the P / P 502 inputs the valve opening degree at the operation end to the channel (2) of the analog input unit (AI). Further, the process flow rate controlled by the operation end is measured by the flow meter 501, and is input to the AI channel (3).
[0040]
The limit switch 506 detects whether the operation end 500 is fully open or fully closed, and the detection signal is sent to the channel (6) of the digital input (DI) of the RTB 400-2, and the air pressure monitoring pressures SW508 and 509 are air pressure sources. The supply of air from 510 is monitored, and when the air pressure drops abnormally (air loss), an air pressure abnormality signal is input to DI channel (7) or (8). The interlock signal output from the channel (4) of the digital output section (DO) of the RTB 400-2 operates the forced operation electromagnetic valve 504 to fully open or close the operation end 500. The hold signal output from the channel (5) operates the opening degree holding electromagnetic valve 505 to hold the opening degree of the operation end 500 at the current state.
[0041]
FIG. 6 shows the configuration of an RTB that inputs and outputs analog and digital signals. The RTB of the present embodiment, except for the functions realized by the CPU and memory from the conventional drive control module described in the cited example etc., is configured with a hardware circuit as an interface function with the target device. It is arranged in the vicinity.
[0042]
The RTB 400 sets the address of a signal handled by the RTB 400 and the serial I / F 401 that converts (P⇔S) data transmitted / received via the serial signal line 300 from serial (S) to parallel (P) or vice versa. The address setting unit 402 and the transmission circuit 403 that outputs a clock signal for the operation of the RTB 400 are provided.
[0043]
The related equipment of the target auxiliary machine is connected by the terminal block 200, and the DI signal is received via the level changer 407 while changing the signal level. 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 sequentially converted into serial signals by the serial I / F 401. At this time, an address is given and sent to the serial signal line 300 at a predetermined timing.
[0044]
On the other hand, the serial signal received by the serial I / F 401 fetches only the address addressed to the own station when there are a plurality of serially connected RTBs. A DO signal such as an interlock is latched at a corresponding address part of the latch circuit 411 and then output to a corresponding operation device via the level changer 412 and the terminal block 420. The operation end command AO signal is converted into analog data via the D / A converter 413 and the DE-MPX 414, amplified by the amplifier 415, and output. As shown in FIG. 1, when the input / output of the analog signal and the digital signal is shared by separate RTBs, only one function need be provided.
[0045]
The above operation in 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 configured by a hardware circuit such as an LSI, and advance the operation of each circuit in a predetermined sequence while stepping with the clock of the transmission circuit 403. The operations of the RTB and the control controller may be performed asynchronously, but a series of input / output cycles of all RTBs connected in series are restricted by the control cycle of the control controller 100. In addition, since other devices and circuits of the RTB 400 are also hardware-configured, there are few malfunctions even in an on-site environment where there is a lot of high temperature, dust or noise.
[0046]
As described above, the RTB of this embodiment does not have a CPU or a memory, and has improved environmental resistance only by hardware. Therefore, the RTB can be installed near the target device in the field without using an air conditioning room. In addition, since the multi-drop connection can be easily performed with a single twisted pair serial cable and the input / output points can be increased as necessary, it is easy to construct or change the system or change the devices inside the RTB.
[0047]
Next, the operation of the plant control apparatus according to the first embodiment will be described. First, serial signal transmission / reception processing will be described. FIG. 7 shows the format of the serial signal and its transmission / reception processing flow. As shown in (a), the serial signal is added with inverted data obtained by inverting them after a start flag, data, address, end flag, and the like. Between the PMDC 200 and the RTB 400, processing is performed while looping back and forth by a dedicated LSI used in each serial I / 204 and 401.
[0048]
As shown in FIG. 6B, when the PCDCM 200 starts data transmission / reception processing (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 using a data rationality check (s105). The rationality check performs reverse data comparison processing, reverse flag check, and timeout determination (s1051). As a result, if the reception from the RTB is normal, the data is transferred to the corresponding address (s1052), and if there is an abnormality, the data is discarded (s1053). Thereafter, the return data transmission processing is automatically started from the RTB 400 side to the PCDCM 200 side (s106). The RTB 400 creates a transmission serial signal (s107) and transmits it to the PCDCM 200 side (s108). When receiving the return signal (s109), the PCDCM 200 performs the data reception process by the rationality check similar to step s105, and takes the data into the corresponding address in the case of normal reception (s110).
[0049]
FIG. 8 illustrates serial signal addresses. As shown in (a), when the PMDC 200 and the RTB 400 are serially connected, the input / output data address of the RTB 400 is set as shown in the table of (b), for example. That is, the output 1 and output 2 addresses transmitted from the PCDCM 200 to the RTB 400-1 are 1 and 2 of the output data address of RTB (1). For example, the output data address 1 is a control command value at the operation end. The illustrated addresses 3 and 4 are unused and are missing numbers. On the other hand, the input 1 and input 2 addresses transmitted from the RTB 400-1 to the PCDCM 200 are 1 and 2 of the input data address of the RTB (1). For example, the input data address 1 is a measured value of the process amount.
[0050]
The serial signal is given an address according to the correspondence table, and is transmitted in the order of address. Usually, analog signals of AI and AO are digitized and expressed by a plurality of bits, so that one is transmitted per frame. However, in many cases, DI and DO digital signals are transmitted together in a single frame.
[0051]
FIG. 9 shows a process flow of the plant protection operation performed by the PCDCM. This processing program is stored in the memory 203 of the PCDCM 200 and executed by the CPU 202. When normal automatic control is performed, the CPU 202 performs the following procedure for each control cycle.
[0052]
First, referring to the normal signal of the CPU 101, it is checked whether the controller 100 is operating normally (s201). If normal, the measured value of the valve opening meter 507 is referred to, and RTB normal diagnosis is performed on the valve opening signal (s202). RTB normal diagnosis is a rationality determination check at the time of the reception process. If the valve position meter signal is normal, a check is made as to whether the valve is operating as commanded (s203). If it is operating normally, the measured value of the valve opening limit switch 506 at the operation end is referred to. If the result of the RTB normal diagnosis (s204) is normal, the value of the opening LS signal is on the normal side ( 1/0) is checked (s205). If normal, the measured values of the air pressure monitoring pressures SW508 and 509 are referred to, and if the result of the RTB normal diagnosis (s206) is normal, the air pressure is checked for abnormalities (s207). If there is no abnormality, the process of the cycle is terminated.
[0053]
On the other hand, if it is determined that there is an abnormality in s201, a hold signal is output considering that the controller is abnormal (s208), and the opening degree of the operation end 500 is held at the current state by the opening degree holding electromagnetic valve 505, thereby enabling the manual mode ( s211). Further, when the result of normal RTB diagnosis by s202 or the like is abnormal (?), An interlock signal is output considering that the RTB is abnormal (s209), and the operation end 500 is moved in the fail-safe direction (fully opened or fully opened) by the forced operation solenoid valve 504. Closed). Further, if any of s203, s205, and s207 is abnormal, the operation end is regarded as abnormal, and an interlock signal is output (s210). In s212, the operation is performed in the fail-safe direction (fully open or fully closed). Preventing the occurrence and spread of
[0054]
As described above, when the control controller 100 is abnormal, the CPU 202 of the PCDC 200 can independently perform the control calculation and interlock the operation end. In the above processing, normal RTB diagnosis or the like may be performed by a dedicated LSI of the serial I / F 204. It is also possible to visualize the protection circuit by software stored in the memory 203 on the CRT of the maintenance tool (workstation) in FIG. 4 and monitor the operation state.
[0055]
As described above, according to the first embodiment, since the input / output points of the PCDC are not fixed by serial connection, it is possible to freely use a standard PCCM corresponding to unique processing different for each operation end such as interlock and hold. Can be easily rearranged, and any system design can be easily performed. In addition, 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 types of operation terminals and instrumentation. As a matter of course, since the PMDC and the target auxiliary machine in the field can be connected by a single serial signal line in principle, the field wiring is greatly reduced.
[0056]
Of course, the number of serial signal lines with the target auxiliary machine is not limited to one. As described above, the serial signal lines may be doubled. Further, in the plant control system, in order to avoid the loss of process data or the like that has a significant influence on the whole, the corresponding measurement point is also made to have a duplex configuration.
[0057]
FIG. 10 shows another embodiment in which the PCDCM and the target auxiliary machine are connected by a plurality of serial signal lines. The difference from FIG. 1 is that the measured values (AI) of the duplicated process flow meters 501a and 501b are transferred to the control controller 100 via dedicated RTBs 400-1a and 1b and DPCMs 200-1a and 1b, respectively. This is the point you are entering.
[0058]
In this embodiment, the input / output of the target auxiliary machine is not integrated into one PCDC, but a PCCM that inputs / outputs a specific signal exclusively is provided separately and connected to the dedicated serial signal line via the RTB. This also maintains system reliability while significantly reducing the number of conventional wires. In this case, since the protection functions unique to the PCCM are bundled in one DPCM, their input / output points are not fixed, and they can flexibly respond to the addition or change of functions or model changes on the auxiliary equipment side. Can be rearranged.
[0059]
As described above, by duplexing the serial line, even if one system (main system) has an abnormality such as disconnection, the function can be taken over by the remaining one system. Furthermore, the system reliability can be further improved by wiring a duplex serial line in preparation for a disaster on a separate route within the power plant. According to the present embodiment, the wiring is greatly reduced by serial communication, and the input / output points are not fixed, so that such a redundant configuration can be easily realized.
[0060]
Next, a second embodiment of the present invention will be described. In the first embodiment described above, the PCCM corresponds to the operation end of the target auxiliary machine on a one-to-one basis, and the control command of the control controller 100 is output to the corresponding operation end via the PCCM. However, even though it is originally a single control function, there are cases where processing is performed while being shared by a plurality of operation ends. For example, in order to accurately control a wide range of flow rates over the entire range, it is necessary to place a large sized valve and a small sized valve side by side and adjust them while linking them together. Incidentally, there are cases where three valves are operated in conjunction with each other in a coal-fired power plant.
[0061]
Conventionally, in this interlock control, an individual command for each operation end is calculated by a control controller and output through each drive control module. In other words, the hardware is divided and processed while having a functionally grouped configuration. In the present embodiment, such a group of interlocking control in terms of function is executed by one PCDM as follows.
[0062]
FIG. 11 is a schematic diagram of a plant control apparatus that performs two-valve interlocking control. The basic configuration of the control device is the same as in FIG. 1, but the target operation ends of the PCDCM 200 are a large flow valve 600 and a small flow valve 700. Although the peripheral devices of each valve are not shown, they are almost the same as in FIG.
[0063]
The PCCM 200 that has received the total flow control command from the CPU 100 executes the two-valve interlocking control program, outputs the opening commands for the large flow valve 600 and the small flow valve 700, and passes through the serial signal line 300 and the RTB 400-1-4. And control. RTB 400-1 (AI / O) and 400-2 (DI / O) are the large flow rate valve 600 and its peripheral devices, and RTB 400-3 (AI / O) and 400-4 (DI / O) are the small flow rate valve 700. And its peripheral devices.
[0064]
The PCDC 200 executes the interlock logic control calculation together with the above-described two-valve interlocking control to protect the plant. The two-valve interlocking control procedure and interlock logic are stored in the memory 203 as a program.
[0065]
FIG. 12 shows an example of a characteristic diagram of the two-valve interlocking control. At 50% or less of the flow rate, only the valve opening degree of the small flow rate valve 700 is controlled in proportion to the flow rate, and during this time the large flow rate valve 600 is fully closed. On the other hand, at 50% or more of the flow rate, the small flow rate valve 700 is kept fully open, and the valve opening degree of the large flow rate valve 600 is controlled in proportion to the flow rate. In accordance with a control command from the controller 100, the PCDM 200 of this example calculates the valve opening degree of each of the large flow valve 600 and the small flow valve 700, and instructs each by serial transmission. Thereby, the range of 0 to 100% of the flow rate can be accurately controlled.
[0066]
FIG. 13 shows a processing flow of the interlock logic. During normal automatic control, it is first determined whether the controller 100 is normal based on the controller normal signal. If it is recognized that the controller is abnormal, an operation end opening degree holding command is output, and the mode is switched to the manual mode (s308, s312). On the other hand, when the controller 100 is operating normally, the measurement signal from each operation end is referred to through the RTB normal diagnosis (s300), and the determination by the following interlock logic is performed.
[0067]
First, an operation check on the small flow valve 700 side is performed. With reference to the opening meter signal of the small flow valve 700, it is checked whether the small flow valve 700 is operating according to the command value (s302). If it is normal, the limit switch signal of the small flow valve 700 is referenced 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 referenced to check whether the air pressure source is normal (s304). When an abnormality of the small flow valve 700 is detected in any of the above s302 to s304 (s310), a large flow valve / small flow valve fully closed (or fully open) electromagnetic valve output is issued and a fail safe operation is performed ( s313). If each determination on the small flow valve 700 side is normal, the operation check is performed on the large flow valve 600 side in the same manner as the small flow valve 700 side in steps s305 to s307, and if an abnormality is detected, fail safe Perform the operation. However, a fail-safe operation may be performed on only one of the interlock control operation ends.
[0068]
The interlock processing procedure is stored in the memory 203, which can be converted into a sequence diagram or a logic circuit diagram using the maintenance tool shown in FIG. 4, and its operation state can be monitored using a CRT.
[0069]
As described above, in this embodiment, the control commands of a plurality of flow valves having the same control function and interlocking relations are calculated by a program stored in one PCDC, and the valves are interlocked by serial connection from the PCCM. Control. The interlocks of these valves are also linked with the logic stored in the PCDCM. As a result, a group 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.
[0070]
In the above embodiment, the interlock 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 a thermal power plant, in addition to this, a large-sized auxiliary machine such as a feed water pump, a recirculation pump, a control oil pump, a fuel pump, and a heavy oil pump performs similar interlocking control with peripheral devices. The present invention can also be applied to such interlocking control, and the same effect as in the embodiment can be obtained.
[0071]
Further, in the range related to the interlock control as in this example, the number of input / output points including the protection function is often 20 or more. However, since this PCDC enables a large number of input / output points by serial connection, it is not necessary to use a specially-designed connector as in the prior art, and the system design is easy and the maintainability can be improved.
[0072]
【The invention's effect】
According to the present invention, a serial IF is provided in the operation end drive module attached to the controller for control and used for input / output with the target auxiliary machine of the plant, and is connected to the target auxiliary machine by one serial signal line. Therefore, there is an effect that the construction of the system can be facilitated and the cost thereof can be reduced, for example, the on-site wiring can be greatly reduced and the operation end drive module can be standardized.
[0073]
In addition, when the operation end drive module is equipped with a CPU that operates independently of the control controller, and when processing specific to the operation end such as interlocking of the target auxiliary machine is executed, the operation end drive is performed by the serial connection described above. Since multiple input / output points of the module are not fixed in hardware, functions can be easily added or changed by freely rearranging the input / output points, improving the controllability and reliability of the system There is.
[0074]
Furthermore, when a plurality of operating ends are inherently linked to achieve one function, these operating ends can be controlled through one operating end drive module without being divided in hardware, thereby improving the control performance of the system. Facilitates fail-safe design.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of a plant control apparatus 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 in FIG. 2;
4 is a configuration diagram of a supervisory control system that performs overall supervisory control of the plant of FIG. 2;
FIG. 5 is an explanatory diagram showing an embodiment of a serial signal line and its connection.
FIG. 6 is a configuration diagram showing an example of an RTB.
FIG. 7 is an explanatory diagram showing a serial signal between PCDCM and RTB and transmission / reception processing thereof.
FIG. 8 is an explanatory diagram of input / output data and its set address on the RTB side.
FIG. 9 is a flowchart illustrating an example of an interlock process performed by a PCCM.
FIG. 10 is a configuration diagram of a plant control apparatus obtained by modifying FIG. 1 and multiplexing serial connections.
FIG. 11 is a block diagram showing interlock control in another embodiment of the plant control apparatus of the present invention.
FIG. 12 is an explanatory diagram showing the sharing of the flow rate with the interlock control of the large flow rate valve and the small flow rate valve.
FIG. 13 is a flowchart showing interlock by the PCDCM in the interlocking control of FIG. 10;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 100 ... Controller for control, 101 ... CPU, 102 ... Memory, 103 ... Transmission interface, 104 ... PI / O interface, 105 ... Internal bus, 200 ... Programmable drive control module (PMDC), 201 ... PI / O interface, 202 ... CPU 203 ... Non-volatile memory 204 ... Serial I / F 300 ... Serial signal line 400 ... RTB (Remote Terminal Box) 401 ... Serial I / F 402 ... Address setter 403 ... Transmission 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, 413 ... D / A conversion 414 DE-MPX 415 amplifier circuit 420 terminal block 500 air Type control valve (operating end), 501 ... process flow meter, 502 ... P / P converter, 503 ... E / P converter, 504 ... forced operation solenoid valve, 505 ... opening holding solenoid valve, 506 ... opening monitoring Limit SW, 507 ... Valve opening degree meter, 508, 509 ... Air pressure monitoring pressure SW, 510 ... Air source, 600 ... Large flow valve, 700 ... Small flow valve.

Claims (4)

It established a process controller for controlling a plurality of process equipment of the plant, provided the operation end drive module included with the controller, connected via a transmission means the process equipment and the module, controls the process equipment In the plant control system
Said operating end drive module, and Rume Mori to store the software specific processing functions in the target operating end, the CP U to execute the software independently of the process controller is provided,
When interlocking control is performed between a plurality of operation ends in order to control a specific process amount, the processing procedure of the interlock control is stored in the memory, and an individual control command value for each operation end is calculated by the CPU. plant control system characterized by being configured to send heat to the operation end through the transmission means. In claim 1,
A processing procedure for interlocking protection of the operation end based on the interlock control is stored in the memory, and the CPU receives data for monitoring abnormal operation of the operation end from each operation end through the serial signal line, A plant control system characterized by operating all or part of the operation end toward the fail-safe side when an abnormality is recognized in the operation end. In claim 1 or 2 ,
The interlocking control of the processing procedure stored in the memory visualize, a monitoring means for displaying a processing operation by the CPU and coupled to the network of the central control equipment room, to be integrally controlled by the computer A characteristic plant control system. In claim 1, 2 or 3 ,
It said plurality of operation terminal performing interlocking control, plant control system is a plurality of flow pump having different plurality of flow valves or feed capacity of different valve opening size.

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