JPH04137010A - Fault diagnostic device for sequencer - Google Patents

Abstract

PURPOSE:To easily and quickly inspect and repair a faulty part by reading a stroke where the execution of the program of a sequencer is stopped, picking up external input included in the stroke by tracing the stroke in a direction opposite to an execution order, and displaying it on a display device. CONSTITUTION:This device is equipped with a means 3 to read the program of the sequencer, a means 3 which traces the stroke where the execution of a read program is stopped in an order opposite to the execution order and picks up the external input included in the stroke, and the display device 6 to display picked up external input. Therefore, the stroke where the execution of the program of the sequencer is stopped is traced in the direction opposite to the execution order of the stroke, and the external input included in the stroke is picked up, and is displayed on the display device 6. Thereby, it is possible to easily inspect and repair the faulty part by inspecting displayed external input.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a fault diagnosis device for a sequencer.

BACKGROUND OF THE INVENTION As a control device for controlling equipment and machinery in a production process, a sequencer is well known, which provides commands for sequentially executing logical operations set on a time axis to force devices to be controlled.

FIG. 4 is a ladder diagram showing an example of a program set in such a computer.

In this ladder diagram, the normally open switch R-SW is a switch built into an external input device, that is, an external device to be controlled. This switch R-3W, a normally closed contact 000a connected in parallel to this, a normally closed contact 001b not connected in series to this parallel part, and a normally closed contact 001
One stroke OO of the program is expressed by the excitation coil 0OOR connected in series to b.

Further, the normally open switch L-3W is also a switch built into the external device to be controlled, that is, an external input. This switch L-3W, a normally closed contact 001a connected in parallel to this, a normally closed contact 000b connected in series to this parallel part, and an excitation coil 001R connected in series to the normally closed contact 000b. So Pro 7 Ram Pond 1st leg 01
is expressed.

Among the above contacts, the normally open contact 000a and the normally closed contact 000b are contacts that operate by excitation of the excitation coil 0OOR, and this excitation coil 000R serves as an output that prompts the external device to perform a predetermined operation. It has become.

Further, the normally open contact 001a and the normally closed contact 001b are contacts that operate by excitation of the excitation coil 0OIR, and this excitation coil 0OIR serves as an output that prompts the external device to be controlled to perform another operation.

That is, in this program, when the switch R-SW in the external device is turned on, the normally closed contact 001 is turned on.
Since the excitation coil 0OOR is on, the excitation coil 0OOR is excited, and an output is given to the external device to prompt a predetermined operation. In other words, process 00 is executed. When the external device starts operating, the switch R-3W returns to off, but at this time, the normally open contact 000a is already on, so the excitation coil 0 is turned off.
00R is self-maintained.

As a result of the operation in step 00 by the external device, when the switch L-SW in the external device is turned on next, the excitation coil 001R is excited, and an output that prompts the external device to perform a predetermined operation is provided. In other words, step 01 is executed. The start of this operation of the external device causes the switch L-SW to
returns to off, but at this time 'l/; open contact 001a
is already turned on, so the excitation coil 0OIR is self-maintained.

FIG. 5 is a diagram showing the program of the above ladder diagram in a normal flowchart. Following the start of step n1,
Steps up to step n2 and step o3 correspond to the process of process OO, and steps up to the next step n4 and step n5 correspond to the process of process 01.

By the way, since the above-mentioned program does not use a status flag or a status counter that indicates the stroke position, that is, it does not use a step flow, even if a failure occurs and the sequencer stops,
It is not easy to find the stroke position where program execution has stopped. As a result, it becomes difficult to identify the cause of the failure.

Therefore, even in the ladder one-way program mentioned above,
Using status flags and status counters that indicate each step of the program, it is expressed as a step-by-step program.
Attempts have been made to make it easier to locate the stopped process in the event of a failure.

Figure 6 shows the status counter C added to the program in Figure 4.
It is a diagram showing a step-by-step program created by adding.

In this program, when the excitation coil 0OOR is excited, the normally open contact 000a is turned on and the status counter C is cleared, thereby confirming that the stroke oO is being executed.

Also, when the exciting coil 001R is excited, the normally open contact 00
1a is turned on and the value of status counter C is incremented to 1, which confirms that step 01 is being executed.

In this case, by identifying the stopped process,
Since the range of the failure location is limited, it is easy to inspect and check the failure location.

However, even when creating a program using the Ste-Knob flow described above, there are large differences in program expression due to individual differences among programmers, and there is no unified programming method. Due to the fact that it has not yet been determined, no diagnostic device has been developed that can appropriately determine failures for sequencers with such programs.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a fault interrupting device for a sequencer that can quickly and easily confirm a fault in a sequencer set with a step-by-step program.

Means for Solving the Problems The present invention provides a method for solving the problems when the operation of a sequencer in which a step-by-step program is set that gives instructions for sequentially executing logical operations to a device to be controlled stops. A fault diagnosis device for a sequencer that diagnoses where in a sequencer program a failure has occurred has a means for reading the sequencer program and a means for reading executed or stopped steps in the read program in the reverse order of execution. This is a fault diagnosis device for a sequencer, characterized in that it includes means for tracing and picking up external inputs included in the process, and a display device for displaying the picked up external inputs.

According to the present invention, a step in the sequencer program whose execution has been stopped is traced in the reverse direction of its execution order, and external inputs included in that step are picked up and displayed on the display device. By checking the external input that has been received, it is possible to easily check and repair the malfunctioning part.

Embodiment FIG. 1 is a front diagram showing an electrical connection configuration between a fault diagnosis device 1 for a sequencer, which is an embodiment of the present invention, and a sequencer 2 whose fault diagnosis is performed by this fault diagnosis device 1. be.

The above fault diagnosis device 1 for a sequencer includes a central processing unit (C
internal ProcessinHUni and below,
3. Read-only memory (abbreviated as CPU)
OnlyMemory: Hereinafter abbreviated as ROM)4
, Random write/read memory (Random^ccess
It is composed of a memory (hereinafter abbreviated as RAM) 5, a display device 6, an interface 7, and the like.

The ROM 4 is a memory in which a diagnostic program for the fault diagnostic device of the sequencer 2 is written, and the CPU 3 executes the program.

The RAM 5 is a memory for storing programs read out from the sequencer 2 by executing the diagnostic program, data used in failure diagnosis processing, and the like.

The display device 6 is a device that has the function of displaying the results of failure diagnosis.

The interface 7 is a device that performs data communication with the sequencer 2 when reading a program or the like from the sequencer 2.

FIG. 2 shows a flowchart showing the procedure of the fault diagnosing device 1 for a sequencer, and FIG. 3 is a ladder diagram showing an example of a program set in the sequencer 2.

The ladder diagram in FIG. 3 is a step-by-step program similar to the program shown in FIG. 6 earlier, and its processing steps are basically the same as those in FIG. 6.

In this program, a step number is assigned to each process. That is, step number 00 is assigned to process 00, and step number 01 is assigned to process o1.

Further, for each process, a mark (hereinafter referred to as a transition) is provided to give an opportunity to move the process from that process to the next process. That is, the transition 00 has a life of 001, and the transition 01 has a transition of a line 01.

These transitions have an element attached to them that indicates the end of the process. That is, line 01 has normally open contact 00 corresponding to excitation coil 0OOR as its element.
0a is connected to the line OO, and the normally open contact 001a corresponding to the excitation coil 001R is connected as an element to the line OO.

That is, in this case, the program executes step 01 and outputs the exciting coil o as an output to an external device (not shown) that is controlled by the sequencer 2.

When the IR is energized, the normally open contact 001a is turned on, and the transition on line 00 triggers the process to move to the next step oO, and when step oo is executed, the exciting coil 000R is output as an output to the external device. When excited,
It is created so that the normally open contact 000a is turned on and the transition of line 01 provides an opportunity to move the process to the next step 01.

Next, with reference to the flowchart of FIG. 2 and the ladder diagram of FIG. 3, the operation of diagnosing the sequencer 2 by the sequencer failure diagnosing device will be described.

When the operation of the sequencer 2 is stopped due to a failure, data communication is started between the sequencer failure diagnosis device 1 and the sequencer 2.

At this time, as shown in FIG. 2, the fault diagnosis device 1 for the sequencer first checks the current state of the step-by-step program shown in FIG. Read out the process, that is, the process when execution is stopped. Specifically, the step number corresponding to the process whose execution has stopped is read. The read step number is stored in RAM5.

In the next step S3, the process portion corresponding to the step number is read out of the program of the sequencer 2.

That is, in FIG. 3, if the execution of the program is interrupted because excitation coil 001R is not excited, line OO, which is a transition, does not trigger the process to move to the next step 00, so in this case, Step number 01 is read out, and the program portion shown in FIG. 3 is read out accordingly. The read program portion is also stored in the RAM 5.

After all, in this case, it is determined that the failure location is within the range of step 01 of the program from the read step number 01.

In the next step S4, the stopped process O1 is traced in reverse order to search for a failure location.

Specifically, as shown by the arrow in FIG. 3, a search is first made from line 00, which is the transition corresponding to the stopped process 01 as No. 2, to the element connected thereto, that is, the normally open contact 001a. .

Since there are no more elements on the line that includes this transition, the next item is the excitation coil 0OI, which is the output.
The search proceeds on the same line from R to the normally closed contact 000b on the left.

Next, as the 0th point, the search proceeds to the switch L-SW side among the switch L-3W and the normally open contact 001a that are connected in parallel to each other on the same line.

As mentioned earlier, these switches L-5' and V are switches built into the external device that is controlled by the sequencer 2, that is, they are external inputs for the sequencer 2, so this switch L-S W is searched so far and is displayed on the display device 6 as a candidate for the cause of the failure.In other words, in the failure diagnosis of this embodiment, it is assumed that there is no failure in the internal gates of the sequencer 2. Therefore, it is excluded as a candidate for failure cause.

There are no other elements on the branch line that surprises the above switch L - SW, even if the search is continued further to the left, so the search path is temporarily moved back to the normally closed contact ooob, and then as the , the search proceeds to the branch line including the normally open contact 001a connected in parallel to the switch L-SW.

Since there is no element in that branch line other than the normally open contact 001a, the search path is temporarily retracted to the normally closed contact 000b, and then the search proceeds to the 0th excitation coil 000R.

Hereinafter, the same procedure as the above-mentioned search on the line including the excitation coil 0OIR is repeated to search for the switch R-SW which is an external input, and this switch is displayed on the display device 6 as a candidate for the failure cause.

Through such a procedure, when external inputs near the stop stroke position of the program of the sequencer 2 are sequentially picked up as failure cause candidates, the failure diagnosis process is completed in step s5.

The operator of this fault diagnosis device 1 semi-automatically performs fault diagnosis by checking external inputs, that is, switches L-3W and R8W on the external device side, which are displayed on the display device 2 as candidates for fault causes. I can do what I want to do.

In addition, in the above embodiment, in order to simplify the explanation, it is assumed that the search for relays in the sequencer 2 itself is not faulty, and only the external input is picked up as a candidate for the fault cause. A well-known processing technique that automatically searches for failures in relays and the like inside the sequencer 2 may be used in combination with the above embodiment.

Effects of the Invention As described above, according to the fault diagnosis device for a sequencer of the present invention, a process in a sequencer program that has stopped execution is read out, the process is traced in the reverse direction of the execution order, and the process is executed. Since the included external inputs are picked up and displayed on the display device, the failure location can be easily and quickly inspected and repaired by inspecting the displayed external inputs.

[Brief explanation of the drawing]

FIG. 1 is a program diagram showing a combination of a sequencer fault diagnosis device and a sequencer, which is an embodiment of the present invention; FIG. 2 is a flowchart showing a fault diagnosis procedure of the sequencer fault diagnosis device; Figure 3 is a ladder diagram showing an example of a step-by-step program set in the sequencer, Figure 4 is a ladder diagram showing an example of a program that does not use step-prolow, and Figure 5 is a ladder diagram of the program set in the sequencer. FIG. 6 is a ladder diagram showing an example of a step-by-step program set in a sequencer. fault diagnosis device for sequencer, 3...CPU, 4-
ROM, 5...RAM, 6 - Display device, 7. Interface agent Patent attorney Number of strokes Keibu 2nd

Claims (1)

[Claims] When the operation of a sequencer that is set with a step-by-step program that provides instructions for sequentially executing logical operations on a device to be controlled stops, which of the programs in that sequencer is A fault diagnosis device for a sequencer that diagnoses whether a failure has occurred at a location includes a means for reading the program of the sequencer, a step in the read program that has stopped execution, and a method that traces the step in the read program in the opposite order of execution. A fault diagnosis device for a sequencer, comprising means for picking up included external inputs, and a display device for displaying the picked up external inputs.