JPH03118601A - Control unit - Google Patents

Abstract

PURPOSE:To decide the abnormality of a user program according to the setting state of a flag by setting the data to a timer area of a memory via the user program to periodically update this data and turning off the flag in a time-up state. CONSTITUTION:A basic program 1 writes the timer set value into the 1st word of a timer area 21 as the initialization. Then one is subtracted from the timer set value and this subtraction result (the current value) is written into the 1st word. While the unsubtracted value written into the 1st word is written into the 2nd word. If the current value and then the previous value are not equal to '0', the current value is defined as the preceding value and -1 is defined as the current value. If the current value is not equal to '0' and the preceding value is equal to '0', the initialization is carried out and a flag SW65 is turned on. No operation is carried out if the current value and then the preceding value are equal to '0'. If the current value is equal to '0' and the preceding value is not equal to '0', a time-up state is decided and the SW65 is turned off with the preceding value set at '0' respectively. When an OFF state of the SW65 is detected during a control operation, a control program 3 judges the abnormality of the program 1 and starts the corresponding error process.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is a control system that inputs a plurality of signals from various control objects, executes a user program or a control program, and outputs control signals to various control objects. Regarding the unit, in particular, the present invention is improved so that the operating state of the unit can be known between a user program and a control program set inside the unit.

<Conventional technology> At process automation and fact machine manufacturing sites, control systems input signals from various sensors, sequencers, etc., execute user programs and control programs, and output control signals. unit is installed.

Such a control unit includes an input/output card that actually sends and receives signals, a CPU card that performs various control calculations, a communication card that participates in communication with the outside, and the like.

A user program for calculating various data is installed in the CPU card as a basic program, and a PID control program and a sequence control program (hereinafter referred to as "control program") are also installed in the CPU card. Here, the basic program is
Communication is performed between the card and the human output card, and this is reflected in the data of the control program, and the calculated control data is reflected in the control program.

In this way, the basic program (user program) and control programs (PID control program and Sequence control program) are used in close contact with each other.

<Problems to be solved by the invention> By the way, basic programs are simple and easy to assemble by users, but they also require communication with other systems.
There is a high possibility of errors occurring compared to a pre-fixed control program.

If an error occurs in the basic program and it stops, the control program may continue to control without noticing the error, even though the data update of the connected input/output section is interrupted, which is bad for the entire system. It can affect everyone.

The present invention aims to solve such problems, and aims to improve the reliability of the entire system by making it possible for the control program to recognize the stoppage of the basic program.

Means for Solving the Problems> The present invention, which has solved the above problems, adds a timer function to the basic program so that it can be read from the control program side, and its specific configuration is as follows. It is.

That is, in a control unit that inputs signals from various controlled objects, executes a user program or a control program, and outputs control signals to the various controlled objects, a timer area in which the user program sets data is stored in memory. a fixed-period task that updates data in the timer area at fixed intervals and sets a flag in the memory when the data reaches a fixed value, and sets the set state of the flag as the operating state of the user program. The control unit is characterized in that it is set in the control program.

Function> In the control unit of the present invention, the basic program writes a timer setting value in the timer area, and the fixed periodic task updates the timer setting value at regular intervals, and when the timer setting value reaches a constant value, turns off the flag. On the other hand, the control program constantly monitors the set state of this flag and starts error processing when it detects that the flag is off.

<Embodiment> FIG. 1 is a diagram showing the main parts of a control unit of the present invention.

In this figure, a basic program 1 is a user program whose specifications are freely set by the user, a memory 2 is set in the control unit, and a control program 3 is a PID control 10 gram and Siegen control program, The periodic task 4 is a program that implements a timer function, and is actually set as a subroutine program of the control program 3.

Furthermore, a 2-word timer area 21 and a 1-bit flag area 22 are set in the memory 2. This flag area 2
2 is called flag 5W65 due to the program specifications.

Here, the basic program 1 writes a predetermined timer setting value in the timer area 21, and the fixed-period task 4 subtracts 1 from this timer setting value every fixed period (for example, 1 second) and monitors the value. When the flag becomes "0", a flag 5W65 is set in the flag area 22. The control program 3 checks the setting state of this flag 5W65 while executing control, and executes normal processing or error processing.

Now, the operation of the periodic task 4 in the control unit of the present invention is shown in the flowchart of FIG.

First, the basic program 1 writes a timer setting value to the timer area 21 as an initial setting.

Note that this setting value is written in the first word of the timer area 22, and in order to realize the timer function, this timer setting value is subtracted by 1, but the subtraction result (current value)
Write it in the first word. The value before subtraction (previous value) written in the first word is written in the second word.

Now, if the current value is "0pa" and 1, and the previous value is also not "0", the current value is set as the previous value, and (current value)-1 is set as the current value.

If the current value is not "0" and the previous value is "0", this is the initial setting, and the flag SW65 is turned on.

If the current value is "0" and the previous value is "0", nothing is done.

If the current value is "0" and the previous value is not "O", time is up, the flag SW 65 is turned off, and the previous value is set to "0".

The control program 3 sets this flag 5W65 during control operation.
If it detects that the basic program is off, it is determined that there is an abnormality in the basic program, and the corresponding error processing is started.

FIGS. 3(a) and 3(b) are diagrams schematically showing a system actually using the control unit 10 of the present invention.

Fig. 3(a) is a diagram showing normal operation, and Fig. 3(b) is a diagram showing normal operation.
) is a diagram showing a case where an abnormality occurs in the basic program.

In FIG. 3(a), communication information from the input/output section 5 is sent to the control program 3 through the basic program 1, and control operations are executed.

Such systems typically include multiple control units 1
0 is connected to an operator station 6 that manages these control units, and this operator station 6 reads out the status of the control unit 10 as necessary and executes other processing such as displaying the control target. ing.

FIG. 3(b) shows a case where some abnormality occurs in the input/output unit 5111 and the basic program 1 is stopped as a result.

At this time, there is no data set in the timer area 22, time is up due to periodic task 4, and flag SW65 is set.
is set off (N), and the control program 3 detects this flag 5W65 off (N) when executing a control operation, and can know that the basic program 1 has stopped.

The control program 3 then performs error processing (AN
; Start Y).

As described above, the control program 3 is a basic
Know when program 1 has stopped.

Incidentally, in the above embodiments, a basic program is employed as the user program, but the present invention is not limited to the basic program, and may be a user's custom task program.

<Effects of the Invention> As described above, the user program sets data in the timer area of memory, updates this data (timer setting value) at regular intervals, and turns off the flag when time-up occurs, and the control program can determine whether the user program is normal or abnormal based on the setting status of this flag, and even if an abnormality occurs on the user program side, it will not have a negative impact on the system, improving system reliability. I can do it.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the main parts of the control unit of the present invention, and FIG.
The figure is a flowchart of a periodic task in the control unit of the present invention, and FIGS. 3(a) and 3(b) are system schematic diagrams for explaining the operation when using the control unit of the present invention. 1...Basic program, 2...Memory, 2
1...Timer area, 22...Flag area, 3...
Control program, 4... Periodic task, 5... Input/output section, 6... Operator station, 10...
Controller unit.

Claims (1)

[Claims] (1) In a control unit that inputs signals from various controlled objects, executes a user program or a control program, and outputs control signals to the various controlled objects, a timer area in which the user program sets data is stored in memory. A periodic task is set for updating the data in the timer area at a certain period, and setting a flag in the memory when this data reaches a certain value, and the set state of the flag is set as the operating state of the user program. A control unit characterized in that the control program is set as: