JPS60251443A - Backup device of programmable controller - Google Patents

Abstract

PURPOSE:To improve the reliability of backup and to execute restoration easily by providing the titled device with two storage devices for storing and copying data on the way and a switching control circuit for detecting abnormality and switching a bus to the normal side. CONSTITUTION:Normally, changeover switches 54-56 are connected to the A side and a CPU1 in a working system is connected to an I/O 6 through a system bus 100 to control the I/O 6. When abnormality is generated in the working system, the changeover switch 54-56 are turned to the B side through the switching control circuit 52 under the condition that a trouble detecting signal 200 in the working system is activated and a trouble detecting signal 200 in a waiting system is inactive. Thus, the control is continued without stopping the system by using the data on the way at a normaly time. When the trouble is restored, backup operation is executed for the waiting system in control operation. If the abnormality is generated in the waiting system, the waiting system is automatically swiched to the working system to continue the control.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides a method for detecting abnormalities in the regular system (secondary standby system (=bumpless)).
- A backup device for a programmable controller that switches over and continues control.

[Technical background of the invention and its problems]

An example of a conventional backup device for a programmable controller is shown in FIG.

In Figure 4, CPU (Central Processing Unit) 1 and PM (Program Storage Device) 3 constitute a programmable controller for the regular system, CPU 2 and PM4 constitute a programmable controller for the standby system, and the regular system is normally in operation. However, when the regular system fails, the bus switching device 5) switches the system bus and operates the standby system.

That is, at all times, the changeover switch 54 in the bus switching device 5
．． 55 and 56 are on the A side (= yes, regular CPU
1 via bus 100 to Ilo (input/output device) 6 (
- The program program of PM3 is combined, (=Therefore, the control operation is performed and (2), and the intermediate data is held in the DM (data storage device) 50 (2). is copied to the DM 51 of

52 is a bus switching DIU control circuit.

If an abnormality occurs in the regular CPU 1 or PM 3 in this state, the failure detection signal 200 from the CPU 1 to the standby CPU 2 becomes active (second 9). (A switching command is output via the Nibus 101, and the changeover switches 54, 55.5
6 to B side (switch between two).

Therefore, the standby CPU 2 is connected to Ilo 6 via the bus 101, and the PM 4 program (
2. Control continues in the standby system.

This performs a backup operation of the programmable controller.

However, the above-mentioned conventional backup device has low reliability because it operates as a single system without backup after the failure signal (2) from the main system is switched, so the standby system operates as a single system without backup. When the failure of the regular system is recovered and the backup is configured with the regular system (= return standby system), the standby system is normally operating (2), but the operator must manually switch over.
There is a problem that the switching operation becomes troublesome.

[Purpose of the invention]

The present invention provides a rational programmable controller backup device that improves the reliability of backup by establishing an equal relationship between the regular system and the standby system, and facilitates the return operation from the standby system to the regular system. The purpose is to

[Summary of the Invention] The present invention provides a bus switching device that switches the system bus between the standby programmable controller and the control operation bumplessly (= continues) when the regular programmable controller becomes abnormal. Backup of the programmable controller - aK + 2, respectively, are connected to the Jt regular system and standby system (-, the control operation side stores intermediate data, and the non-control operation side copies the intermediate data of the control operation side). Equipped with a data recording I'm device and a switching control circuit that detects an abnormality in the regular system or standby system during control operation and switches the system bus to the healthy system (two systems).
There is a system in which the regular system and the standby system are operated equally (two banks up) to improve reliability and operability.

[Embodiments of the invention]

An embodiment of the present invention is shown in FIG.

In FIG. 1, the bus switching control circuit 52 is controlled from the standby system CPU 2 via the bus 101 (in contrast to the conventional system shown in FIG. Failure detection signals 200 and 201 of CPU 2 (
- Therefore, it is directly controlled (2), and the rest is the same as in Fig. 4.

That is, in FIG. 1, the changeover switches 54 and 5 are
5.56 is on the A side (2Aυ, the regular CPU is bus 10)
It is connected to Ilo 6 via 0 for control.

When an abnormality occurs in the normal system (2), the failure detection signal 200 is activated (2) and the changeover switch 54, 55, 56 is activated via the switching control circuit 52 on the condition that the failure detection signal 201 in the standby system is inactive. B Switch to 1t11.

Therefore, the standby CPU 2 uses the intermediate data during normal operation held in the DM 51 T2 to continue control without stopping the system.

In this case, when the failure of the regular system is recovered, a backup operation is performed for the standby system (2) that is in control operation, and when an abnormality occurs in the standby system, the system automatically switches to the regular system (2) and continues control.

Therefore, the reliability of the backup is improved (2), and the return operation from the standby system to the regular system is easy (2).

Another embodiment of the present invention is shown in FIG.

FIG. 2 shows that the DMs 50 and 51 in FIG.
Inside of the bus switching device 5 (-DMAII71J control circuit 53
9 is provided to mutually transfer and copy intermediate data in DMs 50 and 51, but the rest is the same as in FIG.

Therefore, the same bank-up operation as in FIG. 1 is performed. FIG. The system is performing backup operation.

For example CPUI, PM3 and CPU 11 respectively
.

Two sets of regular systems consisting of PM13 (for two CPUs
.

A set of standby systems consisting of PM4 is connected, and bus switching devices 5 and 15 are provided for each regular system (one pair) to detect abnormalities (
A backup is performed using the standby system (-) as opposed to the regular system (2).

The backup procedure is the same as in Figure 1 above.
This makes it possible to bank up multiple sets of regular systems (two sets) using one set of standby systems.

[The young fruits of invention]

As explained above, according to the present invention (2), a highly reliable and easy-to-operate backup device for a programmable controller in which the regular system and the standby system operate on an equal basis (2 backup operations) can be obtained.

[Brief explanation of drawings]

Figures 1 to 3 are circuit diagrams showing each embodiment of the present invention, and Figure 4 is a circuit diagram showing each embodiment of the present invention.
The figure is a circuit diagram showing an example of a conventional backup device. 1.2.11 Central Processing Unit (CPU) 3.4,
13 Program management device (PM) 5.15 Bus switching device 6.16 Input/output device (Ilo) 50.51 Data storage device (DM) 52 Bus switching control circuit 53 DMA control circuit 54, 55.56 Changeover switch 100.101 System bus 200, 201 failure detection signal

Claims (4)

[Claims] (1) A backup device for a programmable controller equipped with a bus switching device that switches the system bus to a standby programmable controller to continue control operations bumplessly when the regular programmable controller becomes abnormal. A regular system and a standby system (two connected, the control operation side stores intermediate data, and the non-control operation side copies the intermediate data of the control operation side, and two sets of data storage devices are connected to each other. A backup device for a programmable controller characterized by having a switching control mechanism that detects an abnormality in a regular system or a standby system and switches the system bus to a healthy system (two systems). (2) The above two sets of data are stored in the bus switching device (
2. A backup device for a programmable controller as claimed in claim 1, further comprising: (2) an operation of a self-switching control circuit (2) for switching buses; (3) The above two sets of data storage devices are connected to a regular bus and a standby bus, respectively (2) Data is copied by controlling the intermediate data transfer of the data storage devices within the bus switching device. 2. A backup device for a programmable controller according to claim 1, further comprising a DMA control circuit for controlling the programmable controller. (4) A backup device for a programmable controller according to claim 1, wherein one set of standby systems is provided for each of the plurality of regular systems (two), and each of the regular systems is backed up by a common standby system.