JP2025012281A - Monitoring and control system and monitoring and control method - Google Patents

Abstract

To provide a monitoring control system that makes it possible to continue monitoring control without causing PLC to go into an error state, eliminates the necessity of creating software that would stop the control and can prevent the occurrence of human error even if one module malfunctions.SOLUTION: A control system that controls equipment 18 in a plant comprises a plurality of modules 11 that are input-output devices for control signals for the equipment 18, a storage unit 15 that stores the correspondence between the modules 11 and the control of the equipment 18, an abnormality detection unit 12 that detects abnormalities in the modules 11, and a control unit 14 that stops the control of the corresponding equipment 18 based on the correspondence stored in the storage unit 15 when an abnormality in a module 11 is detected by the abnormality detection unit 12.SELECTED DRAWING: Figure 1

Description

An embodiment of the present invention relates to a monitoring and control system and a monitoring and control method.

The PLC (Programmable Logic Controller) of the monitoring and control system for water treatment plants, etc., is a digital input module (DI) and a digital output module (D
It is composed of many modules such as an analog input module (AI) and an analog output module (AO).
The configuration of these modules differs for each piece of equipment, but a PLC generally goes down due to an error when one or more modules become abnormal.
In addition, in the case of a module abnormality, it is possible to continue operation by isolating only the abnormal module while retaining the previous value of the signal of the abnormal module (hereinafter referred to as the IO degeneracy function), so that it is possible to continue operation by isolating only the abnormal module. Furthermore, in some cases, measures are taken such as creating software to stop control when a module used in control becomes abnormal.

Patent document 1 describes a controller that has a CPU module and a remote IO module, etc., and controls facility equipment in a plant, etc., and that stops control of all controlled equipment that is the target of control when an abnormality occurs in the CPU module.

Patent document 2 describes a monitoring and control device that can selectively operate equipment that monitors and controls power distribution equipment in either a normal mode that realizes monitoring functions under normal conditions, or a non-normal mode that has a different operating load from the normal mode, and has a selection unit that selects whether to switch to a degenerate mode.

JP 2016-99879 A JP 2019-3292 A

Although shutting down the PLC due to an error in a module does not require much labor and is safe, it is inconvenient because the entire monitoring and control cannot be performed if a single module malfunctions.

Furthermore, when the IO degeneracy function is used, the signal state of the abnormal module becomes unknown, so even if the PLC continues to operate, there is a possibility that the control performed by the PLC is not being performed correctly.

Furthermore, when creating software that stops control, the more controls there are, the more man-hours it takes, and the higher the possibility of human error. Therefore,
This is not widely practiced in LC.

Therefore, in order to solve the above problems, the monitoring and control system of an embodiment is a control system that controls equipment of a plant, and includes a plurality of modules that are input/output devices for control signals to the equipment, a memory unit that stores a correspondence between the modules and the control of the equipment, an abnormality detection unit that detects an abnormality in the modules, and a control unit that, when an abnormality in the module is detected by the abnormality detection unit, stops control of the corresponding equipment based on the correspondence stored in the memory unit.

FIG. 1 is a configuration diagram of a monitoring and control system according to an embodiment. An example of a module configuration according to an embodiment 1 is a table showing an example of modules, variables, and signals according to an embodiment of the present invention; An example of information related to control according to the embodiment An example of a system flow of a monitoring control method according to an embodiment

Below, we will explain the embodiment of the invention with reference to the drawings.

The configuration of a monitoring and control system according to an embodiment is shown in FIG. 1, and the monitoring and control system according to an embodiment will be described below with reference to FIG.

The monitoring and control system according to the embodiment is mainly composed of a PLC 20. The PLC 20 is a controller that controls facility equipment 18, and includes a module 11 which is an input/output device for control signals, an abnormality detection unit 12 which detects abnormalities in the module 11, a target control identification unit 13 which identifies the module in which an abnormality has been detected and a control linked to that module, a control unit 14 which executes a control program for the facility equipment 18, and a storage unit 15 which is a storage device. The computer 10 includes an operation unit 16 which is operated by a user, and a display unit 17 which is a so-called monitoring screen.

The monitoring and control system according to the embodiment is a system that monitors and controls equipment 18 installed in a water treatment plant or the like. Generally, there are multiple pieces of equipment 18, and the monitoring and control system according to the embodiment controls the operation, stop, etc. of the multiple pieces of equipment 18.
It is connected to the LC 20 via a cable L, and control signals are transmitted through this cable L.
For example, if the facility device 18 is a pump, the measured pump discharge flow rate is
0, and when the discharge flow rate is greater than the predetermined threshold, the PLC 2 sets the discharge flow rate to the predetermined threshold.
It is possible to instruct and control the pump, which is the facility equipment 18, to decrease the discharge amount from 0.

Here, the module 11 included in the PLC 20 according to the embodiment will be described using an example of the module configuration in Fig. 2. The module configuration in Fig. 2 is merely an example, and the module configuration is not limited thereto.

IF 21 is an IF module, where IF (Interface) is an abbreviation for interface. The IF module is a module for expanding the input/output (I/O) of the PLC 20, and by being connected to the PLC, the I/O ports of the PLC 20 are expanded, enabling connection to multiple external equipment devices 18.

The power supply 22 is a power supply module and serves to supply power to each unit of the PLC 20 .

The CPU 23 is a CPU module that executes the program of the PLC 20, monitors external input signals, and performs processing for controlling output signals. For example, it can read external input signals, process them according to a program, and change the output signal. The CPU module may also have a communication function for transferring data between modules in the PLC 20. In this case, for example, data obtained from the AI 27, which is an AI (Analog Input) module, is processed by a program and output to the AO 27, which is an AO (Analog Output) module.
8 or a DO (Digital Output) module, DO 26.

DI1 to DI8, DI24 are DI modules (digital input modules), and DI (Digital Input) is an abbreviation for digital input.
It can receive digital input signals to the PLC 20, for example, signals from switches and sensors, and transmit them to the CPU 23. It is also used to process the digital input signals to the PLC 20.

The empty space 25 is a so-called empty space for a module, in which no module is mounted, and is a space in which a module can be added if a new module becomes necessary due to remodeling or the like.

DO1 to DO4 and DO26 are DO modules (digital output modules), where DO is an abbreviation for digital output. The DO modules generate control signals based on the program of the PLC 20 and control the ON/OFF of external devices.

AI1 to AI3 and AI27 are AI modules (analog input modules), where AI (Analog Input) is an abbreviation. The AI module is a module that takes in external analog signals into the PLC and processes them using the program of the PLC 20. For example, an analog input module generally takes in analog signals numbered 1 to 5.
The signal is received in the form of a voltage of V (volts) or a current of 4 to 20 mA (milliamperes), and is converted into a digital signal by an internal analog-to-digital converter (A/D converter).
The PLC 20 is programmed to perform control processing according to the purpose.

AO1, AO2 and AO28 are AO modules (analog output modules), where AO (Analog Output) is an abbreviation for analog output.
This is a module for outputting analog signals from the PLC 20. For example, an internal digital-to-analog converter (D/A converter) can generate analog signals controlled based on the control program of the PLC 20, and output analog signals such as rotation speed and opening to the facility device 18.

Next, the abnormality detection unit 12 has a function of detecting abnormalities such as malfunctions and failures of each of the above-mentioned modules 11. When the abnormality detection unit 12 detects an abnormality, the abnormality detection unit 12 transmits information on at least one of the modules 11 in which the abnormality is detected to the target control specification unit 13.
It also has the function of outputting to.

The target control identification unit 13 identifies a control associated with the abnormal module 11 based on the information on the abnormal module 11 output from the abnormality detection unit 12 described above. In the embodiment, for example, as shown in Fig. 4, when there is a certain control A, there are variables XB1 and XB2 used for the control A. As shown in Fig. 3, the variables XB1 and XB2 each have an associated signal and module DI1. Through the variables XB1 and XB2, it is identified that the module DI1 is associated with the control A. In this way, the target control identification unit 13 can identify the control associated with the abnormal module.

Here, control refers to a control program for controlling a certain facility device (not limited to one device, but can be multiple devices). As a concrete example, if there is a control for "quantity control of three pumps (controlling the operation/stop of multiple pumps based on water level information, etc.)," the control uses signals (variables) of pumps A, B, and C. The relationship between control and facility devices is not limited to one-to-one, and can be one-to-one or one-to-N.

The control unit 14 executes automatic stop if it is enabled, according to the enable/disable of automatic stop predetermined for the control identified by the target control identification unit 13. The enable/disable of automatic stop can be set in advance by the user, and can be set by operating the operation unit 16 on the screen of the display unit 17.

For example, in the embodiment, when the DI1 module becomes abnormal, the control unit 14 automatically stops the control A because the automatic stop is enabled as shown in FIG.
When the automatic stop column shown in FIG. 4 is disabled, control A is not automatically stopped and control A continues.

The storage unit 15 is a so-called storage device. In the embodiment, the information stored by the storage unit 15 is, for example, information on the correspondence between modules, variables, controls, and the like shown in Fig. 3 and Fig. 4, and is stored in a table format for each control.

The operation unit 16 is a tool used by the user for operation, such as a keyboard and a mouse.

The display unit 17 is a so-called monitoring screen that displays the plant status in real time and is operated by the user when the user manually controls the PLC 20.
This is operated when manually changing the automatic stop shown in FIG. 4 from enabled to disabled.

The facility device 18 is a field facility of a plant or the like, and is controlled by the PLC 20. The content of the control A in the embodiment is determined based on information from switches, sensors, and the like installed in the facility device 18.

Next, a monitoring and control method according to the embodiment will be described with reference to a system flow chart of FIG.

In this embodiment, first, the abnormality detection unit 12 detects an abnormality such as a malfunction or failure of the module 11 (S101).

Next, information regarding the detected abnormality is output by the abnormality detection unit 12 to the target control identification unit 13 (S102). This information regarding the abnormality may include not only identification information of the module in which the abnormality was detected, but also information regarding what type of abnormality occurred, the time when the abnormality occurred, and the like.

The target control identification unit 13 identifies whether or not the facility device associated with the module is being controlled based on the identification information of the module in which the abnormality occurred (S103). This is stored in the storage unit 15 in a table format as shown in Fig. 4, for example, and in this embodiment, it is possible to recognize that the control A and the DI1 module are associated with each other.

If there is no control associated with the module in which an abnormality has occurred (No in S103), the system flow in this embodiment ends.

If there is a control associated with the target module (Yes in S103), the target control identification unit 13 determines whether the automatic stop of the control is enabled or disabled (S104). If the automatic stop of the control is disabled (No in S104), the system flow in the embodiment ends. If the automatic stop of the control is enabled (Yes in S104), the target control identification unit 13 outputs that information to the control unit 14, and in the embodiment, the control unit 14 executes the automatic stop of the control A (S105), and the control A is stopped (S106).

As a result of the above, the following effects can be obtained according to the embodiment.

Even if an abnormality occurs in one module, continuous monitoring and control is possible without causing the PLC to go down due to an error, and there is no need to create software to stop control, which reduces the enormous amount of work required for software creation and prevents the occurrence of human error.

Although the embodiment of the present invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. This novel embodiment can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention.
The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.

10... computer, 11... module, 12... abnormality detection unit, 13... target control identification unit, 1
4: control unit, 15: storage unit, 16: operation unit, 17: display unit, 18: facility equipment, 20: PL
C

Claims (5)

In a monitoring and control system that controls plant equipment,
At least one module which is an input/output device for control signals to the facility equipment;
A storage unit that stores a correspondence relationship between the module and the control of the facility device;
an abnormality detection unit that detects an abnormality in the module;
a control unit that stops control of the facility device based on the correspondence relationship stored in the storage unit when an abnormality in the module is detected by the abnormality detection unit;
A monitoring and control system equipped with A target control identification unit that identifies control of the facility device associated with the module from the variables used for control of the facility device stored in the storage unit,
The control unit stops control of the facility device associated with the module in which the abnormality identified by the target control identification unit has been detected.
The monitoring and control system according to claim 1. The storage unit stores whether the stop of the control is valid or invalid in association with the control,
The control unit executes the stop of the control only when the stop of the control is stored as being valid.
The monitoring and control system according to claim 1 or 2. a display unit that displays a correspondence relationship between the module, the variable, and the control of the facility device, the correspondence relationship being stored in the storage unit;
The monitoring and control system according to claim 2. In a control system that controls plant equipment,
Detecting an abnormality in at least one module that is an input/output device for a control signal to the facility device;
outputting information about the abnormality to a target control identification unit that identifies control of the facility device linked to the module from a variable used to control the facility device;
The target control identification unit identifies the presence or absence of a control associated with the module based on the information regarding the abnormality, and then determines whether the suspension of the control is valid or invalid;
When the stop of the control is valid, a control unit that executes control of the facility device stops the control.
Supervisory control methods.

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