JPH03198101A - Control system - Google Patents

Abstract

PURPOSE:To stop the entire operation of a control system or to prevent the malfunction of a local controller itself by providing an original urgent action processing function to the local controller. CONSTITUTION:A local controller 3 is provided with a timer means 4 to monitor the transmission timing of a center controller 1 together with an internal processing means 5 which works urgently when the transmission given from the controller 1 is interrupted for a fixed time and the means 4 is counted up. That is, the means 4 which counts the interval time of the transmission timing and controls this timing is counted up with occurrence of a transmission defect. Thus the means 5 contained in the controller 3 is urgently actuated and performs its original action. Thus it is possible to stop the entire operation of a control system or to prevent the malfunction of the controller 3.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control system that transmits operating information or operating commands via a serial transmission line, and particularly to its fail-safe function.

In recent years, in order to simplify the wiring for transmitting operation information or operation commands from one central controller to a plurality of local controllers, a transmission method using a serial transmission line has been used.

FIG. 3 is a diagram showing an example of a control system using a serial transmission line. In the figure, l is a center controller, 2 is a serial transmission line that conveys operation information or operation commands from the center controller l, and 3 is a serial There are a plurality of local controllers connected to a transmission line 2, and the center controller l transmits various types of operation information or operation commands to each local controller 3 sequentially or simultaneously at a fixed timing via the serial transmission line 2. When each local controller 3 receives the signal, it decodes the contents and performs various operations according to the processing flow shown in FIG.

<Problems to be Solved by the Invention> Conventional control systems are configured as described above, so if there is a failure in the center controller or serial transmission line, the entire system will stop and a temporary transmission failure will occur. There was also a problem where the local controller could malfunction.

The present invention has been made to solve the above-mentioned problems, and it is possible to prevent the entire system from stopping due to failure of the center controller and serial transmission line. The purpose of this invention is to obtain a control system equipped with a fail-safe function that can prevent malfunctions.

<Means for Solving the Problems> In order to solve the above-mentioned problems, a control system according to the present invention connects a plurality of local controllers to one center controller via a serial transmission line. In a control system in which operation information or operation commands are transmitted from a center controller to a local controller at a constant timing via The present invention is characterized in that it includes an internal processing means that performs an emergency operation when the timer means counts up due to an interruption in time.

<Operation> Since the control system according to the present invention is configured as described above, when transmission is interrupted due to a failure of the center controller or the serial transmission line, or when a transmission failure occurs from time to time, the transmission The timer means that monitors the transmission timing by counting the timing interval times counts up, thereby causing the internal processing means within the local controller to perform an emergency operation and perform its own operation. Therefore, stopping the entire system or malfunctioning the local controller can be prevented.

Note that when the transmission from the center controller is restored, it is reset and operates according to the transmission signal.

<Example> An example of the present invention will be described below based on FIGS. 1 and 2.

Fig. 1 is a configuration diagram of the control system, and Fig. 2 is a flowchart thereof. The structure is as follows.

Reference numeral 4 denotes a timer means provided in the local controller 3, which monitors the transmission state by counting the interval time of operation information or operation commands transmitted from the center controller 1 at a fixed transmission timing, and when the count is up, the timer means It outputs a time-over signal to the controller 3.

Reference numeral 5 denotes an internal processing means for emergency operation built into the local controller 3, which operates when a time-over signal from the timer means 4 described above is input, and causes the local controller 3 to operate independently.

In the above configuration, the local controller 3 starts by clearing the timer means 4, and the timer means counts while having operation information or operation commands transmitted at a fixed timing from the center controller l via the serial transmission line 2. The transmission status is monitored to see if there are any ups.

When operation information or an operation command is sent from the center controller l before the timer means 4 counts up, it receives this, decodes the contents, performs the processing operation, clears the timer means 4 again, and starts. and wait for the next information or command.

Meanwhile, the timer means 4 before the next information or command is received.
When WJI 4 . ! Upon operation, the local controller 3 performs internal processing operations, clears the timer means 4 again, starts, and waits for the next information or command.

FIG. 2 is a flowchart showing the above operation. By performing such processing, the local controller 3 operates according to its own internal processing for emergency operation while transmission from the center controller 1 is interrupted. When transmission is restored, normal processing is resumed.

Therefore, even if the central controller or serial transmission line fails, the entire system will not go down, and even if a transmission failure occurs from time to time, the local controller will not malfunction and the system will continue to function. can.

In the above embodiment, the timer means 4 is provided as a separate circuit outside the local controller 3, but if the local controller 3 is configured with a microcomputer or the like, it may be configured with a built-in timer or with software. It performs the same function as the above embodiment.

<Effects of the Invention> As explained above, according to the control system according to the present invention, even if transmission is interrupted due to a failure of the center controller or serial transmission line, or a temporary transmission failure, the local The controller has its own emergency operation processing function, so it can stop the entire system or
It can prevent malfunction of local controller,
This has effects such as improving the reliability of the control system.

[Brief explanation of drawings]

FIG. 1 is a system configuration diagram showing an embodiment of the present invention, FIG. 2 is an operational flowchart thereof, FIG. 3 is a conventional system configuration diagram, and FIG. 4 is an operational flowchart diagram thereof. In the figure, 1 is a center controller, 2 is a serial transmission line, 3 is a local controller, 4 is a timer means, and 5 is an internal processing means.

Claims (1)

[Claims] In a control system in which multiple local controllers are connected to one center controller via a serial transmission line, and operation information or operation commands are transmitted from the center controller to the local controllers at a fixed timing via the serial transmission line, The local controller is provided with a timer means for monitoring the timing of transmission from the center controller, and is further provided with an internal processing means that performs an emergency operation when the timer means counts up due to interruption of transmission from the center controller for a certain period of time. Features control system.