JPH0279594A - Monitor circuit for controller - Google Patents

Abstract

PURPOSE:To attain monitor for defective components in an output hardware circuit of a programmable controller(PC), monitor for defective control auxiliary relay and further for output circuit such as misoutput monitor of control output efficiently by comparing a content of a command given to a slave station with a content outputted by the command. CONSTITUTION:Since all control outputs are OFF normally, a control auxiliary relay 8 and a device selection auxiliary relay 9 are all deenergized normally. Then at control, for example, when master equipments 1, 10-1 are controlled, an equipment selection auxiliary relay (P1)9-1 corresponding to the master equipments 1, 10-1 are activated and an equipment section auxiliary relay (P1)9-1 and a control auxiliary relay (CLX)8-1 or a (OPX)8-2 are energized to give a control command to the master equipments 1, 10-1 by contacts 9B-1, 8B-1 or 8B-2 to apply control. The control output outputted from the PC is inputted again and the internal state and the actually outputted state are compared to monitor defect of the input and output circuit and defect of the control sequence normally.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a PC (
This invention relates to a constant monitoring circuit for a control device using a programmable controller.

(Prior Art) Conventionally, many substation supervisory control systems have been of the function-integrated type, and have been configured with control circuits using auxiliary relays or a range control system.

In this case, since it is a function-intensive type, the 9fl board 1. It had the advantage of reducing the number of panels, but on the other hand, because it is not divided by equipment such as power transmission lines, when maintenance is performed on one equipment, the relevant functions of multiple other equipment may stop. However, there were problems in that the equipment would essentially stop operating, or that it would be difficult to maintain each equipment.

(The problem to be solved by the invention) On the other hand, with the recent development of digital technology, transmission technology, etc., microcomputer application devices such as PCs have been used to construct functionally distributed digital control systems, and systems with high functionality, high performance, and It has become possible to downsize.

Therefore, by providing each equipment unit, such as a power transmission line, with a monitoring and control function for each equipment, the above-mentioned maintenance problems of the conventional method can be solved, and furthermore, it can achieve higher performance, smaller size, and It has become possible to construct control systems that can be standardized.

Furthermore, by digitizing the device as described above, it is possible to automatically monitor the device using software, making it highly reliable and maintenance-free.

Therefore, there is a need to establish a method for automatically monitoring equipment using a PC, and in particular, a means for constantly monitoring an output circuit that outputs control commands to the most important equipment.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a constant monitoring circuit capable of automatic monitoring to a substation control device using a PC.

(Structure of the invention) (Means for solving the so-called problem) In order to achieve the above object, in the present invention, in order to monitor the status of all control outputs from the slave station PC, all outputs from the slave station PC are It was configured to be re-inputted into the circle as a digital input and compared with the control command.

(Function) As a result, the state of the control output held inside the PC can be compared with the input value input as a digital value, that is, the state actually output, and a discrepancy check can be performed. Furthermore, by constantly monitoring malfunctions of all control outputs during non-control, ie, normal times, it is possible to monitor abnormalities in hardware circuitry and software processing.

(Example) Examples will be described below with reference to the drawings.

FIG. 1 is an overall system configuration diagram of a constant monitoring circuit of a control device according to the present invention, and includes a master station 1 that monitors and controls the entire substation, and a plurality of slave stations 2 that are distributed and installed for each piece of equipment such as a power transmission line. The master station 1 and each slave station 2 are connected via a data transmission path 3. Furthermore, a man-machine interface (MMT) 4 is connected to the master station 1, forming a distributed control system.

Next, in the second part, the configuration of the output circuit of the slave station 2 will be explained. The PC installed in the slave station 2 includes a data link section 5 that controls data transmission with the master station 1, an arithmetic section 6, and an input/output section 7 that performs input and output. Also, PC
The control output from the controller drives the control auxiliary relay 8 and the device selection auxiliary relay 9, and the contacts 8 of these auxiliary relays
A, 9A are input from the input/output section 7. Also, regarding the control circuit of the main engine 10, the contact 8B of the auxiliary control relay 8, the contact 9 of the auxiliary device selection relay 9,
It is composed of a combination of B.

The operation of the embodiment will be explained below using FIGS. 2 and 3.

In FIG. 2, since all control outputs are OFF during normal times, the auxiliary control relay 8 and the auxiliary device selection relay 9 are all OFF.

Next, when controlling, for example, when controlling main engine 1.10-1,
A selection command is transmitted from the master station 1 to the slave station 2, which causes the device selection auxiliary relay (P
l) When 9-1 is turned ON, the selection of control of main engine 1.10-1 is completed. Next, the control command is transmitted from the master station 1 to the slave station 2, and if this is an input command, the control auxiliary relay (C
If LX) 8-1 is turned off again, the control auxiliary relay (OPX) 8-2 turns ON, which causes the device selection auxiliary relay (P 1 ) 9-1 and the control JfHnl auxiliary relay (CLX) 8 When (OPX) 8-2 turns ON, the -1 stage connects the contacts 9B-1 and 8 of each auxiliary relay.
The B-1 space gives a control command to the main engine 1°10-1 by 8B-2, and control is performed.

Therefore, under normal conditions, all auxiliary relays are OFF, and by constantly monitoring this, re-inputting the control output output from the PC, and comparing the internal status and the actual output status. It is possible to constantly monitor defects in input/output circuits and control sequences.

FIG. 3 is a monitoring circuit diagram, and each case will be explained using this diagram. First, the PC internal state DOCLX 11 is output to drive the control auxiliary relay 8-1, and its contact 8
XOR with the value DIC1, X12 which is the re-input of A-1.

Take 13 (exclusive OR) and DOCLX 11 to DI
If CLX 12 matches, output 14 is OFF.
(“0”) and no defect is detected, but if there is a mismatch, the output 14 becomes ON<“1”) and the timer 15
After checking for a certain period of time, a defect is detected. This is done in the same way for all output circuits, and all outputs are monitored.

Next, it is monitored that all output relays, including the control auxiliary relay 8 and the device selection auxiliary relay 9, are OFF when not in the selection side leg, that is, at the normal position 16.

First, if any of the input status values 17 of the device selection auxiliary relay 9 is ON+ at position 16 under normal conditions, a failure is detected after a certain period of time is confirmed by the timer 18. Similarly, even if any one of the input status values of the control auxiliary relay 8 is ON at the 16 positions during normal operation, the timer 18 checks for a certain period of time and then detects a defect.

As described above, according to this embodiment, with a simple circuit configuration, by re-inputting and comparing the once-output value, it is possible to constantly monitor failures and malfunctions of the output circuit.

[Effects of the Invention@] As explained above, according to the present invention, since the content of the command given to the slave station is compared with the content output by that command, one of the output bird circuits of the PC It is possible to efficiently constantly monitor output circuits, such as point-by-point failure monitoring, failure monitoring of control relays, and even erroneous output monitoring of control outputs. In addition, the PC that is the applicable controller
Even if the model changes, similar measures can be applied.

Therefore, it is possible to monitor both the hardware and software of the most important control output section of the control system using a PC.
Enables high reliability of equipment.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram of the present invention, FIG. 2 is an output circuit configuration diagram within a slave station, and FIG. 3 is a monitoring circuit diagram. 1... Master station 2... Slave station 3... Data transmission line 4... MMI5... Data link section 6... Arithmetic section 7... Input/output section Fig. 1 Fig. 2

Claims (1)

[Claims] A control master station that collectively monitors and controls equipment at an electrical station, and control slave stations that are distributed for each piece of equipment.These master stations and each slave station are connected via a data transmission path, and each In a control device of a distributed control system that uses a programmable controller (hereinafter referred to as PC) for the slave station, the control command taken from the input section of the slave station PC and the control output output from the slave station PC are compared inside the PC. 1. A constant monitoring circuit for a control device, characterized by comprising monitoring means for monitoring.