JPS61221941A - Back up device for programmable controller - Google Patents

Abstract

PURPOSE:To switch buses optionally and to attain the easy maintenance of a back-up device for programmable controller by adding a manual switching function to a bus switching device which changes automatically a faulty utility system to a spare system to continue a control action. CONSTITUTION:When a utility system is working, i.e., a bus 102 is connected to a bus 100, a manual switch signal 301 is supplied to a manual switching circuit 54. Then a switch command signal 400 is delivered to a CPU of a utility system as long as the healthy signal 201 of a spare system CPU is active. The CPU of the utility system receives the signal 400 and copies the interim data on a data memory DM50 to a DM51. Then the CPU of the utility system delivers a bus switch signal 500 to the circuit 54 at a dividing point of the scanning execution and actuates a bus switching circuit 53 via a bus switching control circuit 52 to connect the bus 102 to a bus 101 at the side of the spare system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a backup device for a programmable controller that arbitrarily switches a bus from a regular system to a standby system to continue control.

[Technical background of the invention and its problems]

FIG. 2 shows a general configuration of a backup device for a programmable controller.

In FIG. 2, a CPU (central processing unit) 1 and a PM (program memory) 3 constitute a regular programmable controller, and a CPU 2 and PM4 constitute a standby programmable controller. The bus switching device 5 switches the system bus from 100 to 101 to operate the standby system when there is an abnormality in the regular system.

An example of a conventional bus switching device is shown in FIG.

31st! l/T: where 50 and 51 are DMs (data storage devices) for the regular system and standby system, respectively, 52 is a bus switching control circuit, and 53 is a bus switching circuit.

Normally, the bus 102 is on the regular side in the bus switching circuit 53, and the regular CPU is connected to the bus 106 via the buses 100 and 102, and control operations are performed according to the PM3 program, and intermediate data is transferred to the DM50. Furthermore, the intermediate data of DM50 is sequentially stored in the D for standby system.
Copied to M51.

In this state, if an abnormality occurs in the regular CPU or PM3 and the healthy signal 200 of the CPU becomes inactive, the command from the bus switching control circuit 52 will The bus switching circuit 53 switches the bus 100 to the bus 1 on the standby side.
Switch to 01.

This allows the standby CPU to connect to buses 101 and 102.
The PM4 program operates the standby system using the normal intermediate data that is connected to the 0M51 and continues control without stopping the system, thereby providing backup for the programmable controller. An action is taken.

However, the above-mentioned conventional backup device.

The system switches to the standby system during control only when an abnormality occurs in the regular system or a major failure occurs, such as when the power to the regular system is cut off, and it cannot be switched arbitrarily between the regular system and the standby system. .

CObject of the Invention] The present invention adds a manual switching function to a bus switching device that automatically switches to a standby system and continues control operation when there is an abnormality in the regular system, thereby making it possible to switch buses at will and simplify maintenance. The purpose is to provide a backup device for a programmable controller.

[Summary of the invention]

The present invention provides a backup device for a programmable controller equipped with a bus switching device that automatically switches the system bus to a standby programmable controller to continue control operations when the regular programmable controller becomes abnormal. Equipped with a manual switching circuit that forcibly switches the system bus between the standby system and the system bus in synchronization with scanning execution.This enables bumpless manual switching between the regular system and the standby system at will, making it easy to perform debugging, maintenance, etc. The aim is to improve operability.

[Embodiments of the invention]

An embodiment of the present invention is shown in FIG.

Fig. 1 is the same as the conventional Fig. 2 except that a manual switching circuit 54 is added to the conventional Fig. 2, and bus switching is forcibly performed via a bus switching control circuit 52. .

When the regular system is in operation, that is, when the bus 102 is connected to the bus 100, the manual switching signal 3 is sent to the manual switching circuit 54.
If you input 01, the healthy signal 2 of the standby CPU 2 will be activated.
Regular CP on the condition that 01 is active
A switching command signal 400 is output to the UI.

When the CPU of the regular system receives the switching command signal 400, it becomes 0M.
After copying the intermediate data of 50 to 0M51.

At the breakpoint of scanning execution, a bus switching signal 500 is output to the manual switching circuit 54, the bus switching circuit 53 is operated via the bus switching circuit 52, and the bus 102 is connected to the bus 101 on the standby side.

As a result, switching from the regular system to the standby system can be performed manually and bumplessly. .

Manual switching from the standby system to the regular system is also possible in a similar manner.

Note that the above explanation distinguishes between the regular system and the standby system, but 2
It is also possible for two systems to mutually operate as a regular system and a standby system.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain a backup device for a programmable controller that facilitates maintenance of a programmable controller equipped with a backup function and allows efficient adjustment in terms of operation.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a system diagram showing a general configuration of a backup device, and FIG. 3 is a circuit diagram showing an example of a conventional bus switching device. 1.2... Central processing unit (CPU) 3.4...
・Program storage device (PM) 5...Bus switching device
6... Input/output device (Ilo) 50, 51... Data storage device! (DM)52...Bus switching control circuit 5
3...Bus switching circuit 54...Manual switching circuit 100, 101.102...System bus 200, 2
01...Healthy signal 300.301...Manual switching signal 400, 401...Switching command signal 500, 501...Bus switching signal Attorney Yoshiaki Inomata (and 1 other person) <1lPFI Hide) ( Battle system) 1st
(!! (〕帛＠＃) (J Division トR; I) Figure 2 (Saiyo Printing (Fuwarze)) Figure 3

Claims (1)

[Claims] A backup device for a programmable controller equipped with a bus switching device that automatically switches the system bus to a standby programmable controller to continue control operations bumplessly when the regular programmable controller becomes abnormal. A backup device for a programmable controller, comprising a manual switching circuit for forcibly switching a system bus between a standby system and a system bus in synchronization with scanning execution.