JPH0581065A - Self diagnostic method for programmable controller system - Google Patents

Abstract

PURPOSE:To increase the number of self diagnosis times so as to improve the reliability of a system by executing self-diagnosis whenever the starting command of an application program is outputted. CONSTITUTION:Initial self-diagnosis is executed in S11 when power is turned on. The self-diagnosis is executed once when power is turned on. When the starting instruction of the application program is given to a programmable controller after self-diagnosis, the system is judged to be during online or not S12. When it is judged to be during online, self-diagnosis S13 whose content is the same as that of S11 is executed. When abnormality is judged as the result, a processing such as the operation stop of the system is immediately executed. When the self-diagnosis processing of S13 is terminated, the application program S14 is executed. It is periodically judged whether the system is set to be offline S15 or not in an execution process. Thus, the reliability of the system is improved since self-diagnosis is executed whenever a processing loop is repeated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a programmable controller system self-diagnosis method for determining the presence or absence of an abnormality in each of a plurality of programmable controllers for process control.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a configuration example of a programmable controller system.

The main controller 21 includes a plurality of programmable controllers (hereinafter referred to as PCs) 22 (PC1),
23 (PC2), 24 (PC3), and 25 (PC4) are connected. Each of PC22,23,24,25,
It has an application program (AP) individually set to execute the control content in charge, and executes only control according to this application program. Each of the PCs 22 to 25 uses a CPU unit composed of a one-chip LSI in order to achieve miniaturization, reduce the number of parts, and improve reliability.

Further, the main controller 21 is composed of PCs 22 and 2
3,24,25 managed, PC22,23,24,25
Command for starting the set application program is individually output to each of the above.

By the way, in the programmable controller system, due to the nature of the system (or equipment) to be controlled, once the power is turned on, the power is not turned off unless special circumstances occur. Therefore, each PC is required to operate for a long period of time without failure or malfunction. In addition, if an abnormality is confirmed, it is necessary to immediately take measures such as stopping the system.

[0006] As a conventional diagnosis of PC,
It was a self-diagnosis such as a memory check when the system was started up.

[0007]

However, in the above-mentioned prior art, the self-diagnosis of the components such as the PC is carried out at the time of starting the system, and therefore, in the system which is continuously operated, the starting is performed. Since it was only once, the self-diagnosis could not be performed regularly or at any time, and it was not possible to deal with abnormalities that occurred during use.

As described above, in order to minimize the occurrence of failures, etc., a one-chip LSI is used and a PC is used.
However, when a bit slice processor is used for the PC, an increase in the number of parts is unavoidable, which causes a decrease in reliability. It is required to be able to perform self-diagnosis.

The object of the present invention was made in view of the above-mentioned circumstances of the prior art. A programmable controller system capable of performing self-diagnosis even at the time of start-up and improving reliability is provided. It is to provide a self-diagnosis method.

[0010]

In order to achieve the above object, the present invention provides a programmable controller system comprising a plurality of programmable controllers each having an application program and a main controller for managing these programmable controllers. Every time the instruction to start the application program is received, the self-diagnosis of the programmable controller is performed.

[0011]

According to the above means, when the command (command) for starting the application program is received, the self-diagnosis of the programmable controller is executed prior to the execution of the application program. Therefore, the number of self-diagnosis can be increased, and the reliability of the system can be improved.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a flowchart showing a self-diagnosis method for a programmable controller system according to the present invention.

As described above, once the programmable controller system is powered on, it is powered off only for maintenance or the like, during which the system is continuously operated. However, when the application program is switched from online to offline, the execution of the application program is stopped, so there is idle time at this time. The present invention pays attention to this point, and performs self-diagnosis in a time period before execution of an application program after online.

First, the first self-diagnosis is executed when the power is turned on (that is, when the system is started) (S).
11). This self-diagnosis has been done conventionally,
It is executed only once when the power is turned on. After this self-diagnosis, it is determined whether or not the start-up instruction of the application program is given to the PC (the start-up instruction is frequently given from the main control device 21) and is online (S1).
2). If it is determined that the user is online, a self-diagnosis with the same contents as in step 11 is executed (S1).
3). If an abnormality is determined as a result of this self-diagnosis, the system is immediately stopped and other measures are taken.
When the self-diagnosis process of step 13 is completed, the application program is executed (S14). In addition, during the execution process, it is periodically determined whether or not it is offline (S15). If it is online, the process returns to step 14 to execute the application program again, and the offline is determined. In this case, the process is returned to step 12 and waits for the online state.

Since the self-diagnosis is performed every time the above processing loop is repeated, the abnormality can be detected at an early stage, and the reliability of the system can be improved.

[0017]

As is apparent from the above, according to the present invention, in a programmable controller system including a plurality of programmable controllers each having an application program and a main controller managing the programmable controllers, the application program is started. Each time the instruction of is received, the self-diagnosis of the programmable controller is performed.
The number of self-diagnosis can be increased and the reliability of the system can be improved.

[Brief description of drawings]

FIG. 1 is a flowchart showing a self-diagnosis method for a programmable controller system according to the present invention.

FIG. 2 is a block diagram showing a configuration example of a programmable controller system.

[Explanation of symbols]

 21 Main Controller 22 Programmable Controller (PC) 23 Programmable Controller (PC) 24 Programmable Controller (PC) 25 Programmable Controller (PC)

Claims (1)

[Claims] 1. A programmable controller system comprising a plurality of programmable controllers each having an application program and a main controller managing the programmable controllers, and self-diagnosis of the programmable controller each time an instruction to start the application program is received. A self-diagnosis method for a programmable controller system, comprising: