JPS6318203B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sequence control device, and more particularly, to a sequence control device in which a microcomputer is configured in a composite type and causes the microcomputer to execute sequence control processing.

BACKGROUND ART Conventionally, in hydraulic power, thermal power, nuclear power plants, etc., sequence control devices that incorporate logic using electromagnetic relays and analog control devices that combine analog circuits have been used. Recently, due to advances in microcomputer technology, these devices have come to be implemented using microcomputers and their program processing. Furthermore, due to the importance of these devices, even higher reliability is required, and this microcomputer also needs to be of a complex type, such as duplexing.

In general computers, when duplication is performed, the data of the calculation results is sent and received between each other and the results are checked.However, in microcomputers, the memory capacity is not large, so this is usually the case. No complicated measures can be taken. Even if two microcomputers that repeat the same sequence of processing start processing at exactly the same time, there will be a lag in the processing over a long period of time unless the microcomputers are physically identical. . If the signals output from these two microcomputers to the plant are ANDed and the actual output is output, due to this processing discrepancy, the correct output will not be executed, which will have a serious impact on the plant. There is a risk that it will cause harm.

The present invention consists of a microcomputer in which it is generally difficult to use complicated means such as a calculator, and it is possible to easily synchronize the same sequence of processing that is repeatedly executed by both microcomputers. It is an object of the present invention to provide a sequence control device which does not have the above drawbacks.

The present invention will be described below based on an embodiment shown in the drawings. FIG. 1 shows a general configuration of the present invention, and shows two microcomputers that repeatedly execute the same processing in one order. 1 indicates process inputs such as analog inputs and contact inputs from the plant. 2a and 2b are respective microcomputers, which take in the process input of 1, and the sequence control processing necessary to control the plant is programmed and executed.

Further, 3a and 3b are interrupt means that interrupt the microcomputers 2a and 2b, and from 2b to 2a, respectively.
b When an interrupt instruction is executed by each program, an interrupt is generated in the other party. Furthermore, an interrupt from the other party is stored as a flag in the internal memory of each microcomputer, although not shown, by a dedicated interrupt program. Reference numeral 4 denotes a circuit that performs an AND operation on the output processing signals 6a and 6b from the microcomputers 2a and 2b to the plant, and outputs an actual output 5 to the plant when both signals match.

Now that the explanation of the configuration is complete, the operation of the present invention will be explained next. FIG. I will also explain. In the configuration shown in FIG. 1, when power is supplied to the microcomputers 2a, 2b and processing starts, initialization processing 10 in FIG. 2 is executed within the microcomputers 2a, 2b. This is a common sense process that is normally performed in a computer system, such as initializing a memory table inside each microcomputer. 10
When the initialization process is completed, an interrupt instruction is executed at the beginning of the process in step 11, and in the case of the microcomputer 2a, the interrupt instruction is sent to the microcomputer 2b side through the interrupt means 3a, and in the case of the microcomputer 2b, An interrupt is applied to the microcomputer 2a side through the interrupt device 3b.

When an interrupt is issued from the other side, a separate interrupt-only program is prepared from the program shown in Figure 2, and the execution of the program shown in Figure 2 is interrupted, and the interrupt-only program is executed. When the program is executed, the fact that there is an interrupt from the other party is stored in the memory as a flag, and the program shown in FIG. 2 is restarted again. When the process in step 11 is completed, in the process in step 12, by checking the flag, it is determined whether or not there has been an interruption from the other party. If there is no interruption, the device remains in a standby state until an interruption is received from the other party. If an interrupt occurs, the process proceeds to step 13.

For example, if the processing on the microcomputer 2a side takes precedence and the processing on the microcomputer 2b side lags behind, then
On the a side, the microcomputer 2b performs the processing in step 11.
After interrupting the server, it enters a standby state through the process of step 12. When the microcomputer 2b side receives an interrupt from the microcomputer 2a side, it is stored in a flag by the interrupt dedicated program on the microcomputer 2b side, and when the processing on the microcomputer 2b side further progresses, the interrupt is sent to the microcomputer 2b side. When the microcomputer 2a side is interrupted by the process 11 and the process proceeds to the process 12, since there has already been an interrupt from the microcomputer 2a side, the process can proceed to the process 13. On the other hand, the microcomputer 2a side also has 12
Since it was waiting in the process of step 13, when an interrupt is generated from the microcomputer 2b side, the process can proceed to step 13. In other words, the microcomputers 2a and 2b are synchronized when proceeding to step 13.

13 is executed immediately after this synchronization is established, output processing from the microcomputer 2a side and the microcomputer 2b side to the plant is executed, and the signals 6a and 6b shown in FIG. 1 are outputted. This signal 6
The outputs of a and 6b are output by an AND circuit 4 to provide an actual output 5 to the plant if both signals match within a certain short period of time. Next, the microcomputers 2a and 2b each have 14
Execute the process. These 14 processes are sequential logic processes, and normally read the process input 1 in FIG. 1, execute the programmed sequence, and prepare for output to the plant. When the process 14 is completed, the process returns to process 11, and the processes 11 to 14 are repeatedly executed.

Note that either the microcomputer 2a side or the microcomputer 2b side may be unable to operate due to some kind of trouble. For such cases, if there is no interruption from the other party based on the judgment in step 12 in Figure 2, the system waits for a certain period of time, and even after that time, there is no interruption from the other party. In some cases, it is also possible to make it run independently. In that case, the output signal of the non-operating side of the AND circuit 4 in FIG.
It is sufficient to set it to always be in the output state in a pseudo manner.

In this way, according to the present invention, it is possible to provide an effective sequence control device that can easily synchronize the processing of two microcomputers.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a block diagram of the present invention, and FIG. 2 is a flowchart showing the operation of the present invention. 1...Process input, 2a, 2b...Microcomputer, 3a, 3b...Interrupt device, 4...
AND circuit for output signals, 5... Actual output to the plant, 6a, 6b... Output signals from the microcomputer, 10 to 14... Each functional block of the flowchart.

Claims (1)

[Claims] 1. In a sequence control device that is equipped with a microcomputer and causes the microcomputer to execute sequence control processing, two microcomputers that repeatedly execute the same process in one order are connected to each other by an interrupt means, and At the beginning of the process, an interrupt is generated to the other party, the interrupt from the other party is confirmed, and the sequence control process is started, and the timing of starting the sequence control process is synchronized with each other, and the sequence control process is started. It is characterized in that output processing to the outside of the device is executed first, and when both output processing signals from the two microcomputers obtained by this output processing match, the output processing signal is outputted. sequence control device.