JPH083749B2 - Monitor device for sequence program control system - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monitor device of a sequence program control system, and more particularly to a playback monitor device of a sequence program control system.

Prior art Sequence program control, in which each step of control is sequentially advanced according to a program that specifies the operation sequence of the equipment to be controlled, corresponds to the operation of the previous step in the assembly line of machine tools and machine tools. It is widely used to automatically perform the next-stage operation.

When performing various kinds of control using sequence program control, it is necessary to monitor whether or not the control is normally performed.
A so-called playback type monitor device is known (Japanese Patent Laid-Open No. 60-238906, etc.). This is one in which the operation patterns (basic patterns) of the components of the sequence control circuit when the equipment is operating normally are sequentially stored in advance, and the operation patterns are stored when the equipment is actually operated. Whether or not is matched with each other is sequentially checked for each corresponding step, and when they do not match, an alarm of occurrence of abnormality is issued.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in such a playback type monitor device, when an abnormality occurs in one element,
After that, there was a problem that monitoring became impossible. That is, an abnormality occurs in one element, and then
When the abnormality is recovered, the change of the element occurs in a step that should not occur, so that a normal element is determined to be abnormal, or an abnormality occurs in one element, and thus matching is performed. The steps of the basic pattern to be shifted are deviated, the matching with the normal pattern cannot be achieved, and the subsequent monitoring becomes impossible. Therefore, if an abnormality occurs in one element, even if the equipment is operating normally thereafter,
There is a problem in that it is necessary to interrupt the work and inspect the abnormal portion, and if the abnormality is caused by a malfunction of the monitor device or the abnormality is immediately recovered, the operating efficiency of the equipment is unnecessarily reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a monitor device of a sequence program control system capable of continuing monitoring even if an abnormal signal occurs in a certain element.

Configuration of the invention An object of the present invention is to compare an operating state change detecting means for detecting a change in the operating state of each element constituting a sequence program control system with an operating pattern of each element and a basic pattern to generate an abnormality. Comparison determining means for determining the presence or absence of the abnormal element, and comparison target checking means for removing the abnormal element in which the abnormality has occurred from the target of the monitor unless it is returned to normal,
In the step where the operating state of the abnormal element has changed, when the operating states of other elements do not change at the same time,
When the basic pattern of the next step is input to the comparison / determination means, and the operating states of other elements simultaneously change,
This is achieved by providing comparison target extraction means for inputting the basic pattern of the step to the comparison determination means.

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

Example Hereinafter, an example of the present invention will be described in detail with reference to 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 work W is sent from a preparation station 1 to a conveyor 4 driven by a motor (M) 3 by a feeding means (SOL1) 2 and at a processing station 5 by a processing means (SOL2) 6. It is subjected to predetermined processing and taken out. Limit switches (LS1, LS2, LS) for detecting the work W are respectively provided at the preparation station 1, the start point and the intermediate point of the conveyor 4, and the processing station 5.
3, LS4) 7 to 10 are provided, and the processing means 6 has a limit switch (LS5, LS6) 1 for detecting the backward end and the forward end thereof.
1,12 are provided. In addition, a safety mat 13 is laid near the processing station 5, and a switch (safety mat S) that outputs a facility stop signal when an operator gets on it.
14 are provided.

FIG. 2 shows the control circuit of the installation shown in FIG.

When the automatic operation button 15 is pressed, the relay means 16a to 16c are activated and the energization is maintained unless the automatic changeover switch (automatic changeover S) 17, the safety mat switch (safety matte S) 14 and the stop switch 18 are activated. . When the work W is in the preparation station 1 and not on the conveyor 4 or the processing station 5, and the processing means 6 is at the backward end (LS
1 and LS5 are on, LS2 to LS4 are off), feeding means (SOL1) 2
Sends the work W onto the conveyor 4 by the operation of the relay means 19a, 19b.

When the work W is on the conveyor 4 and not on the processing station 5 (LS2 or LS3 is on, LS4 is on the conveyor 4).
Is off), and the motor (M) 3 is operated by the operation of the relay means 20a, 20b, and the work W is sent to the processing station 5. When the machining means 6 is not at the forward end (LS6 is off), the work W is at the machining station 5 (LS4 is on), and the reverse relay means (SOL2R) 21c is not operating,
By the operation of the forward relay means (SOL2F) 21d, 21e,
When the work W moves forward, the workpiece W is processed in a predetermined manner, and when it reaches the forward end (LS6 is on), the limit switch for detecting the backward end (LS
When 5) is off and the forward relay means (SOL2F) 21f is not operating, the reverse relay means (SOL2R) 21a, 21b are activated to move backward.

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

FIG. 3 is a block diagram of the monitor device of the sequence program control system according to the embodiment of the present invention.

In FIG. 3, the sequence program changes the operating state change detecting section 31 to the operating state of any element based on the signal input to the operating state input section 30 which inputs the operating state of each element of the equipment to be controlled. To detect whether there was
It outputs to the comparison and determination unit 32. The comparison target extraction unit 33 extracts the pattern of the step to be matched from the basic pattern storage unit 34 in which the basic patterns shown in Table 1 are stored in advance, and outputs it to the comparison determination unit 32. The comparison / determination unit 32 makes a comparison / determination with the output from the operation state change detection unit 31. That is, when the work W is in the preparation station 1 and not on the conveyor 4 and the processing station 5, the automatic operation button 15 is pressed, and the monitoring is started in the state (step 1) in which the feeding means 2 is operated. , The work W is sent out from the preparation station 1, so that the limit switch LS1 (1 → 0)
When the change occurs, the change is detected by the operation state change detection unit 31, and the comparison determination unit 32 compares the operation pattern at that time with the pattern of step 2 of the basic pattern stored in the comparison target extraction unit 33. When these two patterns match, it is determined as “normal” and is output to the determination result output unit 35. Next, the limit switch
When the operating state change detection unit 31 detects that the LS2 changes from (0 → 1) and the feeding means SOL1 changes from (1 → 0), the comparison determination unit 32 compares the patterns in step S3. Done.

Thus, every time the operation pattern changes, the pattern of the new step and the basic pattern corresponding to the step are compared to determine whether the operation pattern is normal. Then, for example, in the state of step 4, when the limit switch LS3 fails and is turned on (1), the operation pattern becomes as shown in Table 2.

Comparing Table 2 and Table 1, in step 4, the limit switch LS3 is turned on (1), and the operation patterns do not match the basic patterns. Therefore, the comparison / determination unit 32 outputs a non-coincidence output signal to the determination result output unit 35, but at the same time, the abnormal element storage unit
It is also output to 36, and the fact that there is an abnormality in the element that has a mismatch, in this example, the limit switch LS3 is stored. When receiving the signal from the comparison determination unit 32, the abnormal element storage unit 36 outputs a signal indicating what the abnormal element is to the comparison target extraction unit 33 and the abnormal element check unit 37.

Then, the limit switch LS1 turns from off to on (0 →
When the change detection unit 31 detects that it has become 1), it is input to the abnormal element check unit 37, it is determined whether or not the changed element is stored in the abnormal element storage unit 36, and the result is Is output to the comparison / determination unit 32. When the element having the change detected by the change detection unit 31 is the element stored in the abnormal element storage unit 36, the comparison determination unit 32 does not perform the comparison determination and is stored in the abnormal element storage unit 36. The comparison judgment is performed only when the element is not a specified element. At this time, for elements that are once determined to be "abnormal", unless there is a return to "normal", even if there is a discrepancy between the basic pattern and the operation pattern, this is ignored and only for the other elements. , The basic pattern is compared and judged.

In this example, it is the limit switch LS1 that has changed, and this is not the element stored in the abnormal element storage unit 36, so the comparison and determination unit 32 directly compares the operation pattern and the basic pattern in step 5. To
The determination result is output to the determination result output unit 35. In this example,
Since there is no abnormality, the signal "normal" is output.

Further, the limit switches LS4 and SOL2F change, but since these are not the elements stored in the abnormal element storage unit 36, the comparison / determination unit 32 compares the operation pattern of that step with the basic pattern. I will do it,
The basic pattern of step 6 following step 5 is a step in which only the limit switch LS3, which is an element with an abnormality stored in the abnormal element storage unit 36, changes, so the operation pattern remains the basic pattern of step 6. Limit switches LS4 and SOL2F when comparing with
Will be erroneously determined to be "abnormal". Therefore,
When the comparison is made in the step in which only the elements stored in the abnormal element storage unit 36 change, the comparison target extraction unit 33 sets the basic pattern of the step advanced by one step to the comparison determination unit 32. Output to. In this example, since step 7 following step 6 is also a step in which only the elements stored in the abnormal element storage unit 36 change, the operation of advancing the steps of this basic pattern is performed twice, and after all, comparison is performed. The target extraction unit 33 outputs the basic pattern of the step advanced by two steps to the comparison determination unit 32. As a result, the comparison / determination unit 32 does not perform the comparison in Steps 6 and 7, but performs the comparison / determination in Step 8.

Next, the limit switch LS5 turns from on to off (1 →
Limit switch LS
When 3 is returned to "normal" for some reason, it changes from ON to OFF (1 → 0), and the change detection unit 31 detects these, the detection signal is compared with the comparison determination unit 32 and the abnormal element check unit.
Output to 37. Here, since the operating states of the elements other than the elements stored in the abnormal element storage unit 36 are also changing, the abnormal element check unit 37 sends the comparison determination execution command to the comparison determination unit.
The data is output to 32, and the comparison / determination unit 32 makes a determination about step 9. At this time, as described above, the pattern comparison is not performed on the limit switch LS3 stored in the abnormal element storage unit 36. But if
If the change in the operating state in step 9 is only that the abnormal limit switch LS3 returns to "normal", it is an accidental change and is not expected in the basic pattern in the first place. When comparing with the basic pattern of the step of, although it is "normal" for the element that should change in the next step,
The judgment of "abnormal" will be made. Therefore, when there is no change in the operating states of the elements other than the elements stored in the abnormal element storage unit 36, the abnormal element check unit 37 does not output the comparison / determination execution command to the comparison / determination unit 32, and in step 9 No comparison judgment is made.

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 by the operating state input unit 30,
The operating state change detection unit 31 detects whether or not the operating state of any element has changed. As a result, if there is no change in the operating state of any of the elements, detection continues until the operating state changes. Operating state change detector 31
Therefore, when it is determined that the operating state of any element has changed, the abnormal element check unit 37 determines that the element is abnormal after the start of monitoring, and is an element that has not yet been restored to normal. (Hereinafter referred to as an abnormal element) is determined. At the start of the monitor, there are no abnormal elements yet, so the result of this judgment is yes, and then
The abnormal element check unit 37 determines whether or not there is an element whose operating state has changed in addition to the abnormal element. This determination result also becomes YES at the start of monitoring, and the step is advanced by one. When starting monitoring, step 0 is 1
Steps are advanced to step 1. Next, it is determined whether the step of the basic pattern corresponding to the step changes only the abnormal element or not.
Determined by 33. At the start of monitoring, this determination result is NO, and in the comparison determination unit 32, the comparison target extraction unit 33 extracts from the operation pattern of step 1 and the basic pattern stored in the basic pattern storage unit, and the comparison determination unit 32 outputs it. The input basic pattern of step 1 is compared to determine whether or not an abnormality has occurred.

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

On the other hand, as a result of the determination, when there is a mismatch between the operation pattern and the basic pattern, it is determined that an abnormality has occurred in the element with the mismatch, and that element is stored in the abnormal element storage unit 36 as an abnormal element. , Returning to the start, the change in the operating state is detected again. Then, when it is detected that the operating state of any of the elements has changed, it is determined whether the element is an abnormal element stored in the abnormal element storage unit 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 element, and the target is matched with the basic pattern. On the other hand, the judgment result is
If no, leave it as is and proceed.

Then, 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 process has not yet moved to the next step, so return to the start,
Again, a change in operating condition is detected. On the other hand, when the operating states of elements other than the abnormal element also change, it is considered that one step has advanced, so one step is advanced,
The steps are from step 1 to step 2.

Next, the comparison target extraction unit 33 determines whether or not the step (step 2 in this case) is a step in which only the abnormal element changes in the basic pattern. If the result is yes, there is always a mismatch for the abnormal element, so there is no point in comparing it with the basic pattern of that step. Therefore, one step of the basic pattern is advanced and the basic pattern of step 3 The operating patterns will be compared. On the other hand, the judgment result is
When the result is NO, the comparison and determination unit 32 performs matching with the basic pattern in step 2 without advancing the step.

According to this embodiment, regarding the element in which the abnormality has occurred,
After that, unless it returns to normal, remove it from the target of the monitor, consider the existence of this abnormal element, and select the step of the basic pattern to be matched, so stop the operation of the equipment unnecessarily. None,
The second and third abnormalities can be accurately detected, and the reliability of the monitor device can be significantly improved. Furthermore, since the elements in which an abnormality has occurred are stored sequentially, even if the equipment stops due to the occurrence of an abnormality, it is possible to grasp all the elements in which an abnormality has occurred and the equipment stops. It is possible to investigate the root cause that led to the above and accurately prevent the recurrence of an abnormality or failure.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the invention described in the claims, and those modifications are also included in the scope of the present invention. Needless to say.

For example, in the above-described embodiment, although it has been described as if some physically independent means are provided in the monitor device, each of the means need not be physically independent means. Instead, for example, each of the functions may be realized by software, and the monitoring device may be capable of performing the above-described operation as a whole.

EFFECTS OF THE INVENTION According to the present invention, it is possible to continue monitoring the sequence program control even after the occurrence of the first abnormality, and to accurately detect the second and third abnormalities.
It is possible to facilitate the restoration of equipment and improve the operating rate of equipment.

[Brief description of 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, and FIG. 2 is a drawing showing its control circuit. FIG. 3 is a block diagram of a monitor device of a sequence program control system according to an embodiment of the present invention,
FIG. 4 is a flowchart showing the monitoring method. W ... Work, 1 ... Preparation station, 2 ... Feeding means, 3 ... Motor, 4 ... Conveyor, 5 ... Machining station, 6 ... Machining means, 7, 8, 9, 10, 11, 12 ......
Limit switch, 13 …… Safety mat, 14 …… Safety mat switch, 15 …… Automatic operation button, 16a, 16b, 16c…
... relay means, 17 ... automatic changeover switch, 18 ... stop switch, 19a, 19b, 20a, 20b, 21a, 21b, 21c, 21d, 21
e, 21f …… Relay means, 30 …… Operating state input section, 31 ……
Operating state change detection unit, 32 ... Comparison determination unit, 33 ... Comparison target extraction unit, 34 ... Basic pattern storage unit, 35 ... Judgment result output unit, 36 ... Abnormal element storage unit, 37 ... Abnormal element Check department.

Claims (1)

[Claims] 1. An operating state change detecting means for detecting a change in operating state of each element constituting a sequence program control system is compared with an operating pattern and a basic pattern of each element,
Comparison determining means for determining whether or not an abnormality has occurred, comparison target checking means for removing an abnormal element in which an abnormality has occurred from the target of monitoring unless the element is returned to normal, and a step in which the operating state of the abnormal element has changed In, when the operating states of the other elements do not change at the same time, the basic pattern of the next step is input to the comparison / determination means, and when the operating states of the other elements change at the same time, the basic pattern of that step is A monitor device for a sequence program control system, comprising comparison target extraction means for inputting to the comparison determination means.