JPH01109412A - Monitor for sequence program control system - Google Patents

Abstract

PURPOSE:To continue the monitoring even when an abnormal signal occurs at a certain element by removing an abnormal element to generate an abnormality from the object of a monitor when the return is not normally executed. CONSTITUTION:An operation condition change detecting part 31 detects whether or not the change is executed to the operation condition of the element of either of the facilities and a comparing object extracting part 33 extracts the basic pattern of the step from a basic pattern storing part 34 and a comparing and deciding part 32 executes the comparing and decision of these outputs. When an operation pattern is not coincident with the basic pattern, the inconsistency signal is outputted to a deciding result output part 35 and an abnormal element storing part 36. The abnormal element storing part 36 outputs a signal to show what the abnormal element is, to the comparing object extracting part 33 and an abnormal element checking part 37. Thus, the element to generate the abnormality is removed from the object of the monitor when it is not returned, the existence of the abnormal element is considered, the step of the basic pattern is selected and therefore, second and third elements can be accurately detected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a monitor device for a sequence program control system, and more particularly to a playback type monitor device for a sequence program control system.

PRIOR ART Sequence program control, which proceeds through each step of control in sequence according to a program that specifies the order of operation of the equipment to be controlled, is used in assembly lines of machinery and equipment, machine tools, etc. It is widely used to automatically perform the next step.

When performing various types of control using sequence program control, it is necessary to monitor whether the control is being performed normally or not, and a so-called playback type monitor device is known as a monitor device for this purpose. (Japanese Unexamined Patent Publication No. 60-238906, etc.). This is because the operating patterns (basic patterns) of each component of the sequence control circuit are memorized sequentially in advance when the equipment is operated normally, and the operating patterns are memorized when the equipment is actually operated. ' is checked in each corresponding step, and if they do not match, an alarm is issued to indicate the occurrence of an abnormality.

Problems to be Solved by the Invention However, in such a playback type monitoring device, there is a problem in that if an abnormality occurs in one element, subsequent monitoring becomes impossible. In other words, when an abnormality occurs in one element and the abnormality is subsequently recovered, a change in that element occurs at a step that should not occur in the first place, so a normal element may be determined to be abnormal, or When an abnormality occurs in one element, the step of the basic pattern to be matched shifts, making it impossible to match it with the normal pattern, and subsequent monitoring becomes impossible. Therefore, if an abnormality occurs in one element, it becomes necessary to interrupt work and inspect the abnormality even when the equipment is operating normally. There is a problem in that when the system recovers immediately, the operating efficiency of the equipment is unnecessarily reduced.

OBJECTS OF THE INVENTION An object of the present invention is to provide a sequence program control system monitor device that can continue monitoring even if an abnormal signal occurs in a certain element.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an operating state change detection means for detecting changes in the operating state of each element constituting a sequence program control system, and to compare the operating pattern of each element with a basic pattern to detect the occurrence of an abnormality. a comparison determination means for determining the presence or absence of an abnormality; a comparison target checking means for excluding an abnormal element in which an abnormality has occurred from being monitored unless the abnormality returns to normal; and a step in which a change has occurred in the operating state of the abnormal element; When the operating states of other elements do not change at the same time, the basic pattern of the next step is input to the comparison and determination means, and when the operating states of other elements change simultaneously, the basic pattern of that step is input to the comparison and determination means. This is achieved by providing a comparison target extraction means for inputting the data into the data.

In the present invention, each of the above-mentioned means does not need to be physically independent means, but it is sufficient that the monitor device has each of these functions and can realize the above-mentioned functions as a whole.

EXAMPLES Hereinafter, examples of the present invention will be described in detail based on the accompanying drawings.

FIG. 1 is a schematic diagram showing an example of equipment monitored by a monitor device of a sequence program control system according to an embodiment of the present invention.

In FIG. 1, a workpiece W is transferred from a preparation station 1 to a motor (M) 3 by a feeding means (SOLI) 2.
It is sent to a conveyor 4 driven by a processing station 5, where it undergoes predetermined processing by a processing means (SQL2) 6, and is taken out. Preparation station 1,
A limit switch (
LSI, LS2. LS3. LS4) 7~l
The processing means 6 is provided with limit switches (LS5, LS6) 11 for detecting its backward end and forward end.
, 12 are provided. In addition, processing station 5
A safety mat 13 is laid near the machine, and a switch (safety mat) S) 14 is provided that outputs an equipment stop signal when a worker gets on the machine.

FIG. 2 shows a control circuit for the equipment shown in FIG.

When the automatic operation button 15 is pressed, the relay means 16a to 1
6c is activated, automatic changeover switch (automatic changeover 5) 17,
Energization is maintained unless the safety mud switch (safety mud switch 1-3) 14 and the stop switch 18 are activated.

When the workpiece W is in the preparation station 1, not on the conveyor 4 or in the processing station 5, and the processing means 6 is at the backward end (LSI and LS5 are on, LS2 to LS4
is off), the feeding means (SOLI) 2 sends the workpiece W onto the conveyor 4 by actuation of the relay means 19a and 19b.

When the workpiece W is on the conveyor 4 and not in the processing station 5 (LS2 or LS3 is on, LS4 is off), the motor (M) 3 is actuated by the actuation of the relay means 20a and 20b. Then, the workpiece W is sent to the processing station 5. The processing means 6 is not at the forward end
(LS6 is off), the workpiece W is in machining station 5 (LS4 is on), and the relay means for retreat (SOL
2R) When 21c is not operating, forward relay means (SOt, 2F) 21d, 21e are activated,
When the workpiece W moves forward and performs the specified processing, and reaches the forward end (LS6 is turned on), the backward end detection limit switch (LS5) is turned off and the forward relay means (SQL2) is turned off.
When F>21f is not activated, the reverse relay means (
SQL2R) 21a and 21b are activated and retreat.

The basic pattern of sequence control for this equipment is shown in Table 1. In Table 1, 0 indicates an off state and 1 indicates an on state.

Table 1 and FIG. 3 are block diagrams of a monitoring device for a sequence program control system according to an embodiment of the present invention.

In FIG. 3, based on a signal input to an operating state input section 30 that inputs the operating state of each element of the equipment to be controlled by a sequence program, an operating state change detection section 31 detects a change in the operating state of any element. Detects whether or not there is a difference, and outputs it to the comparison/judgment section 32. The comparison target extraction unit 33
A pattern of steps to be matched is extracted from the basic pattern storage section 34 in which the basic patterns shown in Table 1 are stored in advance, and outputted to the comparison/judgment section 32. The comparison and determination section 32 compares and determines this with the output from the operating state change detection section 31. That is, the work W
is in the preparation station 1 and not on the conveyor 4 or in the processing station 5, and the automatic operation button 1 is pressed.
5 is pressed and the monitor is started with the feeding means 2 activated (step 1), when the limit switch LSI changes from (l→0) as the workpiece W is sent out from the preparation station 1, the change is It is detected by the operating state change detection i31, and the operating pattern at that time is compared with the pattern of step 2 of the basic pattern stored in the comparison target extracting section 33 in the comparison determining section 32. When these two patterns match, "
It is determined that the result is "normal" and is output to the determination result output section 35.

Next, when the operating state change detection section 31 detects that the limit switch LS2 changes from (0 to 1) and the feeding means 5OLI changes from (1 to 0), the comparison and determination section 32 performs step 3. A comparison of patterns is made.

In this way, each time the operating pattern changes, the new step pattern and the basic pattern corresponding to that step are compared to determine whether the operating pattern is normal. For example, in the state of step 4, if the limit switch LS3 fails and turns on (1), the operation pattern will be as shown in Table 2.

Comparing Table 2 and Table 1, in step 4,
The operating pattern does not match the basic pattern in that the limit switch LS3 is on (1).

Therefore, the comparison/judgment section 32 outputs a mismatch output signal to the judgment result output section 35, but also outputs it to the abnormal element storage section 36, indicating that the mismatched element, in this example, the limit switch LS3, is abnormal. Make me remember what happened. When the abnormal element storage unit 36 receives a signal from the comparison and determination unit 32, it outputs a signal indicating the abnormal element to the comparison target extraction unit 33 and the abnormal element check unit 37.

Following Table 2, the limit switch LSI changes from off to on (0 →
1), when the change detection section 31 detects that the changed element is input to the abnormal element check section 37, it is determined whether or not the changed element is stored in the abnormal element storage section 36.
The result is output to the comparison/judgment section 32. When the changed element detected by the change detection unit 31 is an element stored in the abnormal element storage unit 36, the comparison determination unit 32 does not perform the comparison determination and stores the change in the abnormal element storage unit 36. A comparison is made only when the element is not a stored element. At this time, even if there is a discrepancy between the basic pattern and the operation pattern for the element that was previously determined to be "abnormal", this will be ignored unless it returns to "normal", and the other Only elements are compared and judged with the basic pattern.

In this example, what has changed is the limit switch LSI.
Since this is not an element stored in the abnormal element storage unit 36, the comparison/judgment unit 32 directly compares the operating pattern and the basic pattern in step 5, and sends the determination result to the determination result output unit 35. Output. In this example, there is no abnormality, so a "normal" signal is output.In addition, limit switches LS4 and 5
Although QL2F changes, these are still not the elements stored in the abnormal element storage unit 36, so the comparison determination unit 32 compares the operation pattern of that step with the basic pattern, but in step 5 Next step 60
The basic pattern is a step in which only the limit switch LS3, which is the element with the abnormality stored in the abnormal element memory 1536, changes, so when comparing the operation pattern with the step 60 basic pattern, the limit switch LS4 right and 5OL2F will be incorrectly determined to have an "abnormality". Therefore, when the comparison is made in a step in which only the elements stored in the abnormal element storage unit 36 change, the comparison target extraction B3
3 outputs the basic pattern of the step advanced by l steps to the comparison judgment als32. In this example, step 6
Step 7 following is also a step in which only the elements stored in the abnormal element memory 1B36 change, so the operation of advancing the steps of this basic pattern is performed twice, and in the end, the comparison target extraction unit 33 The basic pattern of the next step is output to the comparison/judgment section 32.

As a result, the comparison/judgment unit 32 does not perform the comparison on steps 6 and 7, but performs the comparison/judgment on step 8.

Next, limit switch LS5 changes from on to off (1→
0), and the limit switch L that was abnormal
When S3 returns to "normal" for some reason and changes from on to off (l→0), and the change detection section 31 detects these, it outputs a detection signal to the comparison determination section 32 and abnormal element check section 37. .

Here, since the operating states of elements other than the elements stored in the abnormal element storage section 36 are also changing, the abnormal element check section 37 outputs a comparison judgment execution command to the comparison judgment section 32, and the comparison judgment section At 32, a determination regarding step 9 is made. At this time, as described above, the pattern comparison is not performed for the limit switch LS3 stored in the abnormal element storage section 36. However, if the change in the operating state in step 9 is simply that the faulty limit switch LS3 returns to "normal", then this is an accidental change and is not what the basic pattern predicts in the first place. Therefore, when comparing with the basic pattern of the next step, it is important to note that the elements that should change in the next step are "normal" but "
A determination of "abnormal" will be made. Therefore, when there is no change in the operating state of the elements other than the elements stored in the abnormal element storage section 36, the abnormal element check section 37 does not output a comparison judgment execution command to the comparison judgment section 32, and step 9
I am trying not to make any comparative judgments about.

FIG. 4 is a flowchart showing the monitoring method.

In FIG. 4, first, the operating state of each element constituting the equipment is input to the monitor device through the operating state input 11S30, and whether there is a change in the operating state of any element is detected by the operating state change detection B31. Detected. As a result, if there is no change in the operating state of any element, detection continues until the operating state changes. When the operating state change detection section 31 determines that there has been a change in the operating state of any element, the abnormal element check section 37 checks whether the element is an element determined to be abnormal after the start of monitoring and is still normal. It is determined whether the element has not returned to normal (hereinafter referred to as an abnormal element). At the start of monitoring, there are no abnormal elements yet, so the judgment result is YES. Next, the abnormal element check section 37 judges whether there are any elements whose operating state has changed in addition to the abnormal elements. . This determination result also becomes YES at the start of monitoring, and the step is advanced by one. At the start of monitoring, step 0 is advanced by one step to become step 1. Next, the comparison target extraction unit 33 determines whether the step of the basic pattern corresponding to that step is a step in which only the abnormal element changes. At the start of monitoring, the determination result is NO, and in comparison determination B32, the comparison target extraction unit 33 extracts the operation pattern from step 1 and the basic pattern stored in the basic pattern storage unit, and inputs it to the comparison determination unit 32. The pattern is compared with the basic pattern in Step 10, and it is determined whether or not an abnormality has occurred.

As a result, when it is determined that there is no abnormality in any element, the next change in the operating state is detected.

On the other hand, if the result of the determination is that there is a mismatch between the operating pattern and the basic pattern, it is determined that an abnormality has occurred in the element with which the mismatch occurred, and that element is stored in the abnormal element storage section 36 as an abnormal element. , the process returns to the start, and a change in the operating state is detected again. Then, when it is detected that there has been a change in the operating state of any element, it is determined whether that element is an abnormal element stored in the abnormal element storage section 36.

If the determination result is YES, there is a possibility that the abnormal element has returned to normal, so the flag is reset, the element is removed from the abnormal elements, and it is matched with the basic pattern. On the other hand, if the determination result is no, leave it as is and proceed to the next step.

Next, it is determined whether or not there is an element whose operating state has changed in addition to the abnormal element. As a result, when it is determined that only the abnormal element has changed, it is considered that the next step has not yet been carried out, so the process returns to the start and detects a change in the operating state again. On the other hand, when the operating states of elements other than the abnormal element also change, it is considered that the step has progressed by one, so the step is advanced by one, and Step 1 is changed to Step 2.

Next, the comparison target extraction unit 33 determines whether the step (in this case, step 2) is a step in which only the abnormal element changes in the basic pattern. If the result is YES, there will always be a discrepancy regarding the abnormal element, so there is no point in comparing it with the basic pattern of that step.Therefore, the basic pattern is further advanced one step, and the basic pattern of step 3 is compared with the basic pattern. Actuation patterns will be compared. On the other hand, the judgment result is
When the answer is NO, the step is not advanced, and the comparison/determination section 32 performs matching with the basic pattern in step 2.

According to this embodiment, an element in which an abnormality has occurred is removed from the monitoring target unless it returns to normal, and the step of the basic pattern to be matched is determined by taking into consideration the existence of this abnormal element. Because we have selected
The second and third abnormalities can be detected with high accuracy, and the reliability of the monitoring device can be greatly improved. Furthermore, since the elements in which the abnormality occurred are stored in sequence, even if the equipment stops due to an abnormality, it is possible to understand all the elements that caused the abnormality, and the equipment will stop. It becomes possible to investigate the root cause of the problem and accurately prevent recurrence of the abnormality or failure.

The present invention is not limited to the above embodiments (various changes are possible within the scope of the invention described in the claims, and these are also included within the scope of the present invention). Needless to say.

For example, in the above embodiments, the description has been made as if several physically independent means were provided in the monitoring device, but each of the above means is a physically independent means. For example, each of the above functions may be realized by software, as long as the monitor device can fulfill the above functions as a whole.

Effects of the Invention According to the present invention, even after the occurrence of the first abnormality, it is possible to continue monitoring the sequence program control, and the second and third abnormalities can be detected with high accuracy, allowing equipment to be restored. This makes it possible to improve the operating rate of equipment.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of equipment monitored by a monitor device of a sequence program control system according to an embodiment of the present invention, and FIG. 2 is a diagram showing a control circuit thereof. FIG. 3 is a block diagram of a monitoring device for a sequence program control system according to an embodiment of the present invention, and FIG. 4 is a flowchart showing a monitoring method thereof. W...work, l...preparation station, 2.
...Feeding means, 3...Motor, 4...Conveyor,
5... Processing station, 6... Processing means, 7.8.9.1O111, 12... Limit switch, 13... Safety mat, 14... Safety mud switch, 15... Automatic Operation button, 16a, 16b, 16c ---Relay means, 1
7... Automatic changeover switch, 18... Stop switch, 19a% 19fi% 20a s 20b s
21a % 21b % 21c 521d %21e
%21f---Relay means, 30... Operating state input section, 31... Operating state change detection section, 32... Comparison determination section, 33... Comparison target extraction section, 37... Abnormal element Chi...ri part. 4Figure 2

Claims (1)

[Claims] an operating state change detection means for detecting a change in the operating state of each element constituting the sequence program control system; a comparison determination means for comparing the operating pattern of each element with a basic pattern and determining whether an abnormality has occurred; A comparison target checking means for excluding an abnormal element in which an abnormality has occurred from being monitored unless the abnormal element returns to normal, and a step in which the operating state of the abnormal element changes, the operating state of other elements does not change at the same time. and a comparison target extracting means for inputting the basic pattern of the next step into the comparison and judgment means when the operating state of the next step changes at the same time, and inputting the basic pattern of the step to the comparison and judgment means when the operating state of another element changes at the same time. A monitor device for a sequence program control system, characterized in that: