JPH01109404A - Trouble diagnosis supporting system in sequence controller - Google Patents

Abstract

PURPOSE:To facilitate a cause analysis by extracting a rule including an action control signal or a condition response signal from a prescribed rule group and successively executing a rule extracted. CONSTITUTION:An operation control part 14 includes a CPU 26 to execute a prescribed action command through a sequencer 12 to a machine tool 10 and execute a trouble diagnosis supporting processing and a memory 28 to store a rule group used in a supporting processing. Based on a first rule group corresponding to plural action control signals and a condition response signal sent from the machine tool 10 and a second rule group corresponding to the action control signal and the condition response signal to change after a prescribed time in accordance with this, the CPU 26 extracts the action control signal or the condition response signal related to the troubled place. Thus, when the machine tool 10 is troubled, or becomes an abnormal condition and is stopped, the trouble cause can be easily analyzed by executing successively the first and second rule groups.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a failure diagnosis support system for a sequence control device that controls a controlled object such as a machine tool using a sequence program. When issuing sequential operation commands to a controlled object according to a sequence program, it is now possible to easily diagnose when an abnormality or failure occurs in the machine tool by tracing back the predetermined operation rules. The present invention relates to a failure diagnosis support system.

[Background of the Invention] Generally, in order to reduce the number of personnel and improve operating efficiency of equipment such as machine tools or work robots, sequence control is used to set the operating procedure using a sequence program and perform a desired machining function. The device is widely used. In a system using such a sequence control device, the sequence program is sequentially decoded by the sequence control device and supplied as a control signal to a controlled object such as a machine tool.

Then, each part of the controlled object operates based on the control signal, and when a predetermined operation is completed, a detection signal is generated from a detection means such as a limit switch or sensor, and this is used as an operation transition state signal of each part of the controlled object. Output to said sequence.

On the other hand, the sequence detects, based on the detection signal, that each part to be controlled has completed a predetermined operation in response to the control signal, processes the next sequence program step, and repeats this in sequence. By doing so, a desired processing function is performed on the controlled object. In this case, in a machine tool using such a sequence control device, if a failure or abnormality occurs in the machine tool and it stops, it is necessary to discover the cause, maintain it, and repair it.

By the way, the sequence program for controlling the operation of the machine tool is created by a designer or programmer with specialized knowledge.
Created by In this case, for sequence control devices that can describe control sequentially in a flowchart, etc., by sequentially tracing each step of the program that the device is executing, you can find the point where the program stops and analyze the cause of the failure. It is relatively easy to do so. However, it is not possible to use the above method in random logic type sequence control devices.Therefore, it is generally not possible for operators with the same knowledge as designers and programmers to trace control logic one by one. By doing so, we are analyzing the cause of the failure. For this reason, it has been pointed out that there is a problem in that only experienced experts can analyze the cause of failures or abnormalities.

[Purpose of the Invention] The present invention has been made to overcome the above-mentioned disadvantages, and when a failure or abnormality occurs in a controlled object such as a machine tool, it can be easily handled by a general worker without the need of an expert with specialized knowledge. It is an object of the present invention to provide a failure diagnosis support system for a sequence control device that allows easy cause analysis.

[Means for Achieving the Object] In order to achieve the above-mentioned object, the present invention provides a failure diagnosis support system for a sequence control device that controls the operation of a controlled object according to a sequence program. A first method for associating a plurality of operation control signals outputted to the operation unit with a status response signal sent from the corresponding operation unit based on the operation control signal.
a second rule group that associates the operation control signal with a state response signal from an operation unit that should change after a predetermined period of time according to the operation control signal, and designation of the operation control signal or the state response signal. According to the above-mentioned first and second
and extraction means for extracting a rule including the operation control signal or status response signal from the rule group, and by sequentially tracing back the extracted rules, it is possible to support inference of the cause of failure. do.

[Embodiments] Next, preferred embodiments of the failure diagnosis support system for a sequence control device according to the present invention will be described in detail with reference to the accompanying drawings.

In recent years, due to the development of knowledge engineering, certain causal relationships have been
A then BJ (if A is true, then B is also true) is converted into a rule and stored in a database, and expert systems and artificial intelligence are being developed for use in various inferences. On the other hand, with recent advances in sequence control devices, the state of input and output at a certain point in time, that is, the operation control signal from the sequence control device to each operation unit that makes up the controlled object, and the status response that indicates the operation state of each operation unit. It is possible to monitor the status of signals, etc.

The fault diagnosis support system according to the present invention uses the above-described method of forming rules in the expert system, and supports inference by associating the above-mentioned operation control signals and status response signals and forming rules. This is what I did.

FIG. 1 is an overall configuration diagram of a system using a sequence control device to which a failure diagnosis support system according to the present embodiment is applied. In this case, the system includes a machine tool 10 that performs a predetermined operation on a workpiece, a designer, a programmer, etc.
a sequencer 12 that controls the operation of the machine tool 10 based on a sequence program created by, etc.;
An operation control unit 14 that creates a sequence program by operating the machine tool IO via the sequencer 12
It basically consists of. Note that between the machine tool 10 and the sequencer 12 and between the sequencer 12 and the operation control unit 1
4 are connected by interfaces 16 and 18.

The sequencer 12 includes a memory 20 in which a sequence program is stored, a CPU 22 that sequentially processes the sequence program, and an interface 16 that transfers operation control signals based on the sequence program to the machine tool 10 and controls the machine tool according to the operation control signal. 10 transition states, an I10 port 24 that forwards state response signals to the CPU 22.

The operation control unit 14 controls the machine tool 10 via the sequencer 12.
A CPU 26 that issues a predetermined operation command to the machine tool 10 and reads the transition state of the machine tool 10 corresponding to the operation command, and performs a failure diagnosis support process to be described later, and a memory 28 that stores a group of rules to be described later used in the support process. and an I10 port 30 for transmitting and receiving operation control signals to the machine tool 10 and status response signals indicating transition states of the machine tool 10.

In this case, as will be described later, the memory 28 stores operation units such as various actuators of the machine tool 10 driven by operation control signals, and the status of limit switches etc. that detect when the actuators have performed a predetermined operation. A group of rules that are associated with the status response signal from the detection means are stored.

A display 34 and a keyboard 36 are connected to the I10 port 30 via an interface 32.
Via this keyboard 36, operation commands are given to the failure diagnosis support system or the machine tool 10, and the status of the machine tool 10 can be monitored through the display 34.

On the other hand, the machine tool 10 is configured as shown in FIG. 2, for example. That is, this machine tool 10 performs drilling on the workpiece W using the drill 38,
It basically consists of a processing section 40 and a processed section 42. In the machining section 40, the drill 38 is placed on the base 44.
A feed motor 46 that is displaced in the direction is fixed. In this case, the drive shaft 48 of the feed motor 46 has the workpiece 4
A ball screw 50 extending toward 2 is integrally attached, and a moving table 52 is screwed onto this ball screw 50.

A spindle unit 56 that supports the rotating shaft 54 of the drill 38 is attached to the moving table 52, and a driving motor 58 that drives the rotating shaft 54 is attached to this spindle unit 56. The drive shaft 60 of the drive motor 58 and the rotating shaft 54 supported by the spindle unit 56 are connected by a belt 66 via pulleys 62 and 64. Here, the position of the moving table 52 is detected by three limit switches LSI, LS2, and LS3 arranged along the ball screw 50. That is, the limit switch LSI detects that the movable table 52 is at the cutting start point of the drill 38.

Further, the limit switch LS3 detects that the moving table 52 is at the forward end.

In the workpiece portion 42 , a workpiece mount 70 is fixed onto a base 68 , and a workpiece W is positioned and fixed to the workpiece mount 70 by a clamp jig 72 .

That is, the clamp jig 72 includes a clamp cylinder 74 fixed to the workpiece mount 70 and a support member 78 whose one end is pivoted to the cylinder rod 76 of the clamp cylinder 74 and whose middle part is fixed to the workpiece mount 70. and a clamp member 80 pivotally supported by the clamp member 8.
The workpiece W is positioned and fixed by the other end of the workpiece W. In this case, the clamping state and unclamping state of the work W by the clamp jig 72 are determined by the two limit switches L.
Detected by S4 and LS5, respectively.

Note that the base 68 includes a tank 84 for storing cutting oil 82.
is mounted, and the cutting oil 82 is supplied to the workpiece W via a pipe line 90 by a pump 88 driven by a cutting oil supply motor 86.

A system using a sequence control device to which the failure diagnosis support system according to the present embodiment is applied is basically configured as described above, and its operation and effects will be explained.

Here, the sequence program for controlling the operation of the machine tool 10 is set by the designer as a time chart shown in FIG. 3, and after the programmer creates a ladder diagram using relay symbols etc. based on this time chart. , a logical conditional expression is determined and created from the ladder diagram by a translation program of the sequencer.

In the case of the time chart in FIG. 3, when the sequence program is started, the machine tool 10 first starts with the clamp jig 7.
2 clamps the workpiece W, and the moving table 52 in the machining section 40 moves forward from the retreat end to the cutting start point.Next, the drive motor 58 is driven to rotate the drill 38 and the cutting oil 82 is applied to the workpiece W. It is supplied and the cutting operation begins.

When the moving table 52 moves to the forward end, the rotation of the drill 38 and the supply of cutting oil 82 are stopped, and then the moving table 52 moves to the backward end. Finally, the clamp jig 72 becomes unclamped, and the series of operations ends.

In the above operation, the sequence program is sent from the sequencer 12 to each operation unit such as the clamp cylinder 74, the feed motor 46 of the moving table 52, the drive motor 58 of the drill 3B, and the cutting oil supply motor that make up the machine tool. The correspondence relationship between the operation control signals sent out based on the operation control signals and the state response signal that responds to the sequencer 12 indicating that each operation unit has performed a predetermined operation according to these operation control signals and entered the planned transition state is as follows. The result will be as shown in the figure.

Next, the operation of the machine tool IO explained in the time chart of FIG. 3 will be explained in terms of the relationship between the operation control signal for each operation unit of the machine tool IO from the sequencer 12 and the state response signal when each operation unit operates. . That is, as shown in FIG. 4, when the sequence program is started and the operation control signal Y2 is sent from the sequencer 12 to the clamping cylinder 74, the clamping cylinder 74 clamps the workpiece W and the limit switch LS4 is activated. A status response signal X8 is generated and transferred to the sequencer 12. After confirming the status response signal X-, the sequencer 12 outputs an operation control signal Ys (advance without cutting) to the feed motor 46 of the moving table 52 to be operated next.

When the moving table 52 reaches the cutting start position, the limit switch LS2 transfers the status response signal Xs to the sequencer 12. Thereafter, the operation control is similarly performed in the order shown in the time chart of FIG.

Here, the relationship between the operation control signal Yt (i=1.2, . . . ) and the status response signal Yes, this causal relationship is r if X then
It can be expressed using the rule "Y5". This relationship is made into rules for all control logics and stored in the memory 28 of the operation control unit 14 as a first rule group.

On the other hand, what state and how much time does the machine tool 10 change in response to the operation control signal Yt, that is, what state response signal X i * 1 is generated from what unit of operation?
The causal relationship showing whether is obtained is ' if Y= the
It can be expressed using the rule n Xt+1 J. This relationship is made into a rule for all control logic, and as a second rule group, the memory 28
Store it in

Therefore, if the machine tool IO fails and stops in a certain state, the operation control section 14 can monitor the operation control signal Y1 from the sequencer 12 and the status response signal Xi from the machine tool 10. In this case, for example, the display 34
, an inquiry is made as to why a certain operation control signal Y is not sent from the keyboard 36.

Based on this inquiry, the CPU 26 searches the memory 28 and extracts the rule containing Y from the first rule group.The CPU 26 then compares the status response signal Xi of each extracted rule group with the monitored Xi. , state response signal Xi
Extract those for which is not true. Then, the CPU 26 searches the memory 28 for the extracted X direct, and extracts a rule that includes Xl in the second rule group. Furthermore, a new operation control signal Y included in each of the extracted rules is added.
, , are confirmed on the monitor. The above steps are repeated and the first and second rule groups are sequentially traced back to infer the cause of the failure.

FIG. 5 shows the operation sequence of the machine tool 10 shown in the time chart of FIG. 3 and the first rule group and second rule group using the operation control signal Yi and the status response signal XI shown in FIG. This is a diagram. In FIG. 5, sequence 12 is a status response signal X, and when there is an operation control signal Y2.
is generated, and then in response a status response signal X2
is generated, and so on.

Note that the first rule group and the second rule group are each rif
X1then Y1+ if Y, then X
1*1J represents the above-mentioned causal relationship.

For example, if it is assumed that the limit switch LS4 has failed and the status response signal X2 is not generated, the operator inquires of the operation control unit 14 as to why the operation control signal Y4 is not present. Therefore, the CPU 26 extracts a rule including Y4 from the first rule group. In this case, it can be seen that this is because X does not exist. Next, from the second rule group, this
Extract the rules that include , and if there is no X4, it is Y.

It turns out that this is because it is not possible. Furthermore, a rule containing Y3 is extracted from the first rule group, and it is found that the reason why Y is absent is because X is not valid. Next, from the second rule group,
By extracting the rules that include Y2, we find that the reason why there is no X3 is because there is no Y8. Furthermore, when we extract the rules that include Y2 from the first rule group, we find that the reason that there is no Yz is because there is no X2. I understand. In this way, by sequentially repeating the first and second rule groups and going back, it is possible to infer that the machine tool 10 has stopped because the limit switch LS4 has failed and the status response signal X2 has not been generated. I can do it.

[Effects of the Invention] As explained above, the fault diagnosis support system according to the present invention provides a first system for associating a plurality of operation control signals given to an operation unit of a controlled object with a status response signal sent from the operation unit. Based on a rule group and a second rule group that associates the operation control signal with a status response signal from an operation unit that should change after a predetermined time according to the operation control signal, the operation control signal or the operation control signal related to the failure location is determined. The system is configured to automatically extract state response signals. Therefore, when the machine tool to be controlled stops due to a failure or abnormal condition, it is possible to trace back the first and second rule groups in order to prevent it from being handled by an expert with special experience. This makes it possible to analyze the cause of failure.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments.
Of course, various improvements and changes in design are possible without departing from the gist of the present invention.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of a system using a sequence control device to which a failure diagnosis support system according to the present invention is applied; FIG. 2 is a configuration diagram of a machine tool to which a failure diagnosis support system according to the present invention is applied; Figure 3 is a time chart showing the operating procedure of the machine tool shown in Figure 2, Figure 4 is an explanatory diagram of the relationship of each signal between the sequencer and each operation unit of the machine tool, and Figure 5 is the same as in Figure 3. FIG. 2 is an explanatory diagram of the relationship between a sequence shown in a time chart and first and second rule groups. 10...Machine tool 12...Sequencer 14
...Operation control unit 16, □, 18...Interface 20...Memory 22...CP
U24... Tsukasa 10 boat 26... cpu28... memory 30... I10 port 34...
Display 36...Keyboard 38...Drill 40...Machining section 42...Working part
W...Work LSI~LS5...Limit switch FIG, 5

Claims (1)

[Claims] (1) A failure diagnosis support system for a sequence control device that controls the operation of a controlled object according to a sequence program, wherein a plurality of operation control signals output to a plurality of operation units forming the control object and the operation control signal a first rule group that associates the state response signal sent from the corresponding operation unit based on the operation control signal, and the state response signal from the operation unit that should change after a predetermined time according to the operation control signal and the operation control signal. a second rule group to be associated with each other; and an extraction means for extracting a rule including the operation control signal or the status response signal from the first and second rule groups based on the specification of the operation control signal or the status response signal, 1. A failure diagnosis support system for a sequence control device, characterized in that it can support inference of a cause of a failure by sequentially going back through the rules.