JP2019079458A - Process controller - Google Patents

Abstract

To shorten a cycle of communication between a controller and an input and output module connected to an external field device to achieve higher speed and higher accuracy in control in a process controller.SOLUTION: An analog input part 24, an analog output part 25, a digital input part 26, and a digital output part 27, which have conventionally been divided into different modules, are collected in one input and output module 2, and an input and output control part 22 is in charge of output data distribution and input data collection. Output data is loaded on down data delivered from a controller unit 1 as a master device to the input and output module 2 as a slave device, and input data is loaded on up data returned from the input and output module 2 to the controller unit 1 in response thereto. Consequently, input and output signals can be updated through one reciprocate communication, permitting achievement of higher speed and higher accuracy in control.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a process control apparatus for controlling an industrial plant or the like, and more specifically, using a programmable controller such as a distributed control system (DCS) or a programmable logic controller (PLC). Process control apparatus for controlling field devices.

In plant facilities in factories, power generation facilities, refuse incineration facilities, water treatment facilities, etc., to control a large number of various types of field devices (pressure gauge, thermometer, flow meter, motor, electromagnetic relay, etc.) collectively Process controllers centered on programmable controller units are widely used.
FIG. 3 is a schematic block diagram of one process control device in the distributed control system described in Patent Documents 1 and 2 and the like.

  The control device includes a controller unit 100 connected to an operator console (not shown) via a network line 107 such as a LAN, an analog input module 101 to which the field device 106 is connected, an analog output module 102, and a digital input module 103, respectively. And a digital output module 104, and a base rack 105 provided with a bus that is a collection of input and output signal lines. The controller unit 100 includes a microcomputer (hereinafter, abbreviated as a "microcomputer" according to common use) including a CPU, a ROM, a RAM, and the like to execute various arithmetic processing. Further, as shown in FIG. 4, the analog input module 101 includes a microcomputer 1011 and an analog input unit 1012. The other input or output modules 102 to 104 basically have the same configuration as this analog input module 101.

  The controller unit 100, the analog input module 101, the analog output module 102, the digital input module 103, and the digital output module 104 are attached to the base rack 105, and each input or each signal is connected via a bus provided in the base rack 105. Communication between the output modules 101-104 and the controller unit 100 is performed. The field device 106 includes various devices such as a motor, an electromagnetic relay, and various sensor switches, as well as devices such as a pressure gauge, a flow meter, and an indicator as disclosed in Non-Patent Document 1 . In FIG. 3, one field device 106 is connected to one input or output module 101 to 104, but in practice, a large number (for example, 16 or 64) can be connected to one input or output module 101 to 104. Etc.) can be connected.

  In this control device, communication of a master-slave system in which the controller unit 100 is a master unit and each input or output module 101 to 104 is a slave unit is performed via a bus provided in the base rack 105. By the communication, input data collected by the field device 106 connected to each input module 101, 103 is sent from the input module 101, 103 to the controller unit 100. Conversely, based on the output data sent from the controller unit 100 to each of the output modules 102, 104, the output modules 102, 104 control or drive the field device 106 connected thereto.

  As described above, it is possible to connect a plurality of field devices 106 to each of the input or output modules 101 to 104, but the number may vary depending on the configuration of plant equipment to be controlled. The amount of data exchanged between the controller unit 100 and each input or output module 101-104 depends on the number of field devices 106 connected to each input or output module 101-104. Therefore, when the number of field devices 106 connected to the input or output modules 101 to 104 is large, the cycle of transmission and reception of signals between the controller unit 100 and each input or output module 101 to 104 is set long. There is a need. On the other hand, even when the number of field devices 106 connected to the input or output modules 101 to 104 is small, four reciprocation of signals is performed between the controller unit 100 and each input or output module 101 to 104. There is a need. The time required to send and receive one round trip signal varies depending on the type of module connected to the bus, but if, on the average, it takes 10 msec to send and receive one round trip signal, the communication cycle is 40 msec It becomes. That is, the signal can be updated only in a 40 msec cycle.

  Generally, the temporal variation of detection signals by temperature sensors, flow sensors, etc. in plant equipment etc. is relatively slow, so conventionally, the length of the signal update cycle as described above has hardly been a problem. On the other hand, in recent years, the monitoring and control targets by such process control devices have been expanded, and for example, in monitoring control in steel manufacturing processes etc., in addition to control at normal speed, higher speed monitoring processing is required. It has become to.

Unexamined-Japanese-Patent No. 2005-148802 (FIG. 1) Unexamined-Japanese-Patent No. 2007-233930 (FIG. 1)

"Field top product information", [online], Yokogawa Electric Corporation, [search on July 24, 2017], Internet <URL: https://www.yokogawa.co.jp/fld/top/fld- top-jp.htm>

  The present invention was made to solve the above problems, and its main object is to shorten the cycle of communication between the controller unit and the input module or output module, and to perform high-speed, high-precision control. Providing a process control device capable of

The present invention, which has been made to solve the above problems, executes a predetermined operation based on information collected by one or more external input field devices, and based on the result of the operation, an external output field Process control apparatus for controlling or driving equipment, comprising:
a) A controller unit that includes an operation unit that performs operation processing for control, and a communication control unit that controls communication with the post-entry output module;
b) An analog input unit that collects analog input signals from one or more analog input field devices, an analog output unit that outputs an analog output signal to one or more analog output field devices, and one or more digital inputs Control unit for controlling communication between a digital input unit for collecting digital input signals from a field device for the digital output, a digital output unit for outputting a digital output signal to one or more digital output field devices, and the controller unit And the communication control unit, the analog input unit, the analog output unit, the digital input unit, and the digital output unit, and the output data received from the controller unit via the communication control unit In the form that field devices for analog output and field devices for digital output can be used While distributing, while converting the input data received from the field device for analog input and the field device for digital input via the analog input unit and the digital input unit into a form that can be processed by the controller unit, the data is integrated An input / output module including an input / output control unit;
c) a base rack on which the controller unit and the input / output module are mounted, and signal lines for communication between the controller unit and the input / output module are integrated;
It is characterized by having.

  In the process control apparatus according to the present invention, an analog input unit, an analog output unit, a digital input unit, and a digital output unit that handle signals of different types (that is, analog format and digital format) are combined into one module (input / output module Aggregated to). Then, in one input / output module, data obtained from an external field device through an analog input unit or a digital input unit, and controlling or driving an external field device through an analog output unit or a digital output unit. The input / output control unit aggregates and distributes the data to be processed. Therefore, by exchanging signals between the communication control unit of the controller unit and the communication control unit of the input / output module via the communication line in the base rack, the information collected by one or more external input field devices is It is possible to control and drive external output field devices based on the above.

  In the process control device according to the present invention, preferably, the communication control unit of each of the controller unit and the input / output module uses the controller unit as a master unit, and the input / output module as a slave unit. Communication may be performed.

Specifically, in the process control device according to the present invention, the downstream data transmitted from the controller unit to the input / output module is input / output control unit of the input / output module via the analog output unit and the digital output unit. Output data to be output to the field device for analog output and the field device for digital output,
Upstream data transmitted to the controller unit in response to the downstream data being received by the input / output module is converted into an analog input field through the analog input unit and the digital input unit by the input / output control unit. The input data acquired from the device and the field device for digital input may be included.

  In the process control device according to the present invention, downlink data is sent from the communication control unit of the controller unit, which is the master unit, to the input / output module, which is the slave unit, and the communication control unit of the input / output module that received this goes up to the controller unit. Reply the data. The controller unit can acquire the input data necessary for the control operation in the operation unit by the exchange of the signal of one reciprocation, and the input / output module outputs the target field for the control value and the command value determined by the control operation. It can be given to the equipment.

  In this case, the input / output module transmits each downlink data from the controller unit to the input / output module and subsequently transmits / receives uplink data from the input / output module to the controller unit. The output signal to the field device may be updated and the controller unit may collect the input signal by each field device from the input / output module.

  Since the arithmetic processing by the arithmetic unit of the controller unit and the transmission and reception of data by the communication control unit of the controller unit can be performed in parallel, the period of the arithmetic processing (arithmetic period) and the period of data transmission and reception (communication period) are It does not matter if it is asynchronous. Of course, the operation cycle and the communication cycle may be synchronized.

  According to the process control device according to the present invention, the number of signal round trips between the controller unit and the input / output module can be reduced. For example, when one round-trip communication time between the controller unit and the input / output module is determined to be, for example, 10 msec on average as described above, even if the number of points of the field device is small and the amount of data to be transmitted / received is small It takes an average of 10 msec to send and receive The conventional process control device configured as shown in FIG. 3 receives at least four round trip signals as described above to control and drive the output field device while receiving input data from the input field device. Since communication is required, the communication cycle must be 40 msec. On the other hand, in the process control device according to the present invention, only one round trip signal exchange is required if the number of field devices is small. Therefore, it is possible to shorten the cycle of updating the signal for controlling the output field device and updating the signal read from the input field device, thereby making it possible to increase the speed and accuracy of the control.

  Further, in the conventional process control device, even when the number of field devices to be used is small, it is necessary to use a plurality of input or output modules. On the other hand, according to the process control device according to the present invention, when it is possible to use a single input / output module when the number of field devices may be small, the device can be made smaller and lighter. . As a result, the process control device can be introduced also to small-scale equipment that has been difficult to introduce by conventional devices.

1 is a schematic block diagram of a process control apparatus according to an embodiment of the present invention. FIG. 2 is a schematic view showing the format of data exchanged between a controller unit and an input / output module in the process control device of the embodiment. The schematic block block diagram of the conventional process control apparatus. The schematic block diagram of the analog input module in the conventional process control apparatus.

Hereinafter, a process control apparatus according to an embodiment of the present invention will be described with reference to the attached drawings.
FIG. 1 is a block diagram of the main part of the process control device of this embodiment.

The process control device of the present embodiment includes a controller unit 1, an input / output module 2, and a base rack 3. As shown, one controller unit 1 may be provided, but two controllers may be provided in the case of duplexing to improve reliability. Also, the input / output module 2 can be duplicated.
The base rack 3 is a bundle of a plurality of signal lines for interconnecting the connection portions 30 and 31 including connectors for mounting the controller unit 1 and the input / output module 2 and the two connection portions 30 and 31. And an input / output bus 32.

  The controller unit 1 includes, as functional blocks, a control arithmetic unit 11 that executes arithmetic processing for process control, a communication control unit 12 for performing communication with the input / output module 2, and a connection unit of the base rack 3 And an interface unit 13 including an input / output connector connected to the interface unit 30. The substance of the control arithmetic unit 11 and the communication control unit 12 is mainly configured of the microcomputer 10 including a CPU, a ROM, a RAM and the like, and the function stored in the ROM is realized by executing the program stored in the ROM by the CPU. . However, in order to speed up the calculation in the control calculation unit 11, a dedicated hardware circuit such as a digital signal processor that executes a specific calculation process may be provided.

  The input / output module 2 includes a communication control unit 21 for communicating with the analog input unit 24, the analog output unit 25, the digital input unit 26, the digital output unit 27, and the controller unit 1, and each input The input / output control unit 22 controls input / output of data via the units or the output units 24 to 27 and an interface unit 23 including an input / output connector connected to the connection unit 31 of the base rack 3. Similar to the controller unit 1, the substance of the communication control unit 21 and the input / output control unit 22 is mainly configured of the microcomputer 20 including a CPU, a ROM, a RAM and the like, and each program is executed by the CPU by executing the program stored in the ROM. The function of the functional block is realized.

  The analog input unit 24 in the input / output module 2 is substantially the same as the analog input unit 1012 provided in the analog input module 101 in the conventional device shown in FIG. That is, in the process control apparatus of this embodiment, the analog input unit 24, the analog output unit 25, the digital input unit 26, and the digital output unit 27 which are divided into a plurality of modules in the conventional apparatus are integrated into one input / output module 2. It is aggregated. Then, in order to distribute output data to the analog output unit 25 and the digital output unit 27 and also to combine input data input through the analog input unit 24 and the digital input unit 26, the input / output control unit 22 It is provided.

Next, the process control operation in the process control device of this embodiment will be described.
In the process control apparatus of this embodiment, communication of a master-slave system is performed in which the controller unit 1 is a master unit and the input / output module 2 is a slave unit. The communication cycle is prepared in three types of 10 msec, 40 msec and 80 msec, and the user can select an appropriate cycle from among them. When only one input / output module 2 is used, that is, when duplexing of the input / output module 2 is not performed, the shortest communication cycle of 10 msec can be selected. However, the numerical value of the communication cycle is an example, and can be set to an appropriate cycle.

  In the controller unit 1, the control operation unit 11 performs a predetermined operation for controlling a motor or the like that is the field device 4 according to a preset program, based on data corresponding to an input value by the field device 4 as described later. A process, for example, PID calculation is performed to calculate a control value or the like. Since the arithmetic processing by the control arithmetic unit 11 can be performed when necessary data is obtained, it is executed every operation cycle that is asynchronous with the communication cycle. However, the operation cycle and the communication cycle may be synchronized.

  The communication control unit 12 creates downlink data (see FIG. 2A) in which a predetermined header is added to output data such as the control value to be transmitted to the input / output module 2. This signal format may be any predetermined format. The downlink data is sent from the communication control unit 12 of the controller unit 1 to the communication control unit 21 of the input / output module 2 through the interface unit 13, the input / output bus 32 of the base rack 3, and the interface unit 23 of the input / output module 2. The communication control unit 21 of the input / output module 2 analyzes the header in the received data, and recognizes that it is the data sent to the input / output module 2 itself.

The communication control unit 12 of the controller unit 1 executes the transmission of the downlink data to the communication control unit 21 of the input / output module 2 every communication cycle (for example, 10 msec) determined as described above. The transmission of the downlink data by the communication control unit 21 is performed in parallel with the arithmetic processing by the control arithmetic unit 11, and the communication control unit 21 transmits output data such as the control value obtained by the arithmetic processing in the immediately preceding arithmetic cycle.
If the communication control unit 21 of the input / output module 2 recognizes that the data is not the data addressed to the input / output module 2 from the analysis result of the header in the received data, the communication control unit 21 may ignore the data .

  When the communication control unit 21 of the input / output module 2 receives the downlink data sent from the controller unit 1 and the output data in the data is passed to the input / output control unit 22, the input / output control unit 22 first The detection data obtained by the field device 4 connected to each of the analog input unit 24 and the digital input unit 26 is received. The analog input unit 24 includes an analog-to-digital converter, converts a detection signal which is an analog value input from the field device 4 into a digital value, and passes it to the input / output control unit 22. The digital input unit 26 appropriately converts the control value and the instruction value input from the field device 4 as necessary, and passes the converted value to the input / output control unit 22.

  Subsequently, the input / output control unit 22 distributes the control value and the instruction value based on the output data received immediately before from the communication control unit 21 to the analog output unit 25 and the digital output unit 27 according to the field device 4 of the output destination. Do. The analog output unit 25 includes a digital-to-analog converter, converts control values and instruction values that are digital values into analog values, and outputs the converted values to the connected field device 4. On the other hand, the digital output unit 27 appropriately converts the given control value and instruction value as necessary, and outputs the converted value to the connected field device 4 respectively.

  On the other hand, after the communication control unit 21 of the input / output module 2 receives downlink data and passes output data to the input / output control unit 22, the input / output control unit 22 receives the input units 24 and 26 during the communication cycle immediately before that. Data received from the field device 4 via the input / output control unit 22 is received from the field device 4, and the data are aggregated to create input data. Further, a predetermined header is added to the input data to prepare uplink data (see FIG. 2B). The input data may include a confirmation signal of downlink data received immediately before that. Then, the communication control unit 21 of the input / output module 2 sends the upstream data to the communication control unit 12 of the controller unit 1 via the interface unit 23, the input / output bus 32 of the base rack 3, and the interface unit 13 of the controller unit 1. Do.

  The communication control unit 12 of the controller unit 1 analyzes the header in the data received from the input / output module 2 and recognizes that it is the data sent to the controller unit 1. When receiving the uplink data, the communication control unit 12 of the controller unit 1 extracts data corresponding to an analog input value or a digital input value by the field device 4 from the input data and passes it to the control operation unit 11. Then, as described above, the control calculation unit 11 executes predetermined calculation processing based on the input value. The processing from the transmission of downlink data to the input / output module 2 until the communication control unit 12 of the controller unit 1 described above completes the reception of uplink data is performed in one communication cycle.

  As described above, in the process control device of the present embodiment, transmission of downstream data from the controller unit 1 to the input / output module 2 and transmission of upstream data from the input / output module 2 to the controller unit 1 in response thereto are Output of new instruction signals and control signals to the field devices 4 respectively connected to the analog output unit 25 and the digital output unit 27 by exchanging the data of the reciprocation, and the analog input unit 24 and the digital input unit 26 respectively. Reading of a new signal input from the connected field device 4 is completed. That is, in the conventional device, one round trip communication is sufficient, although four round trip communication is required between the controller unit and the plurality of input / output modules. As a result, when the communication cycle of one reciprocation is set to 10 msec, signal updating can be performed at intervals of 10 msec, whereas updating of signals can be performed only at intervals of 40 msec in the related art.

  The above-described embodiment is merely an example of the present invention, and it goes without saying that changes, modifications, or additions can be made as appropriate within the scope of the present invention and still be covered by the appended claims.

DESCRIPTION OF SYMBOLS 1 ... Controller unit 10, 20 ... Microcomputer 11 ... Control arithmetic part 12, 21 ... Communication control part 13, 23 ... Interface part 2 ... Input-output module 22 ... Input-output control part 24 ... Analog input part 25 ... Analog output part 26 ... Digital input unit 27 ... Digital output unit 3 ... Base rack 30, 31 ... Connection unit 32 ... Input / output bus 4 ... Field device

Claims (4)

A process control device that executes a predetermined operation based on information collected by one or more external input field devices, and controls or drives the external output field device based on the result of the operation,
a) A controller unit that includes an operation unit that performs operation processing for control, and a communication control unit that controls communication with the post-entry output module;
b) An analog input unit that collects analog input signals from one or more analog input field devices, an analog output unit that outputs an analog output signal to one or more analog output field devices, and one or more digital inputs Control unit for controlling communication between a digital input unit for collecting digital input signals from a field device for the digital output, a digital output unit for outputting a digital output signal to one or more digital output field devices, and the controller unit And the communication control unit, the analog input unit, the analog output unit, the digital input unit, and the digital output unit, and the output data received from the controller unit via the communication control unit In the form that field devices for analog output and field devices for digital output can be used While distributing, while converting the input data received from the field device for analog input and the field device for digital input via the analog input unit and the digital input unit into a form that can be processed by the controller unit, the data is integrated An input / output module including an input / output control unit;
c) a base rack on which the controller unit and the input / output module are mounted, and signal lines for communication between the controller unit and the input / output module are integrated;
A process control apparatus comprising: The process control device according to claim 1, wherein
A communication control unit of each of the controller unit and the input / output module performs communication according to a master-slave system, using the controller unit as a master unit and the input / output module as a slave unit. The process control device according to claim 2,
The downstream data transmitted from the controller unit to the input / output module is input to the field device for analog output and the field device for digital output via the analog output unit and the digital output unit of the input / output module. Including the output data to be output,
Upstream data transmitted to the controller unit in response to the downstream data being received by the input / output module is converted into an analog input field through the analog input unit and the digital input unit by the input / output control unit. A process control device comprising input data obtained from a device and a field device for digital input. The process control device according to claim 3,
The input / output module outputs an output to each field device for each transmission / reception of one round-trip reception of uplink data from the controller unit to the input / output module and reception of uplink data from the input / output module to the controller unit thereafter A process control apparatus characterized in that the controller unit updates signals from the input / output module and collects input signals from each field device.

Images