JPH02253306A - Fault diagnosing device - Google Patents

Abstract

PURPOSE:To decrease the software quantity and at the same time to attain a quick diagnostic operation by performing the comparison in sequence between an actual state signal and the data on action condition table and deciding the occurrence of abnormality in a cycle where no coincidence is obtained from the comparison. CONSTITUTION:A CPU 8 stores the states of the starting and arriving terminal elements which are decided by the cycles working before each cycle forming a sequence in an action condition table 6 for each cycle based on the data on a cycle line chart table 5. When the abnormality is decided based on a fact whether each cycle is through within a reference time counted by a timer 7, the CPU 8 compares sequentially the actual signal states of the start and arriving terminal elements 1a of an equipment 1 to be controlled which are inputted via a programmable controller 2 with the data on the table 6 for each cycle. Then the CPU 8 decides the occurrence of abnormality in a cycle where no coincidence is obtained from the comparison and detects a faulty element. Thus a fault can be quickly and accurately diagnosed with a small quantity of software.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a fault diagnosis device that diagnoses a fault in a controlled device controlled by a programmable controller based on a sequence program stored in a memory.

<Prior art> Conventionally, as this type of failure diagnosis device, for example,
There is one described in Japanese Patent No.-148178. This fault diagnosis device is attached to a programmable controller that controls a controlled device equipped with a human and an output element based on a sequence program stored in memory, and a cycle counter that counts cycle numbers according to the operation steps of the controlled device. The computer detects an abnormality by monitoring the cycle number of the cycle counter, and diagnoses the cause by searching the sequence program. Then, this computer uses its software to find the cause of the failure from the signal states of the output element and reaching end element of the operation step corresponding to the cycle number at the time of the abnormality occurrence, and selects a program corresponding to this failure cause from among the above sequence programs. At the same time, the found program is simulated to find the operation switching failure condition of the output element, and this failure condition is output to the alarm display section.

<Problems to be Solved by the Invention> However, in the conventional fault diagnosis device described above, a computer searches for a program corresponding to the cause of a fault from among a sequence program that is described in detail at the level of a ladder diagram (expanded connection diagram). Since it sequentially simulates the found program to find the operation switching failure condition,
The drawback is that the amount of software needed for this is enormous and that diagnosis takes a long time. Furthermore, if a sequence program, ie, a ladder diagram, which is stored in the memory of the programmable controller is incorrectly input, there is a drawback that an accurate search for the cause of the failure cannot be made and correct failure diagnosis cannot be performed.

On the other hand, as a simple fault diagnosis method, there is a method of time monitoring based on a cycle diagram that sequentially describes the cycle number, source end, destination end, output element, reference time, etc. of each cycle that makes up the sequence. This cycle diagram has the disadvantage that the accuracy of diagnosis deteriorates because the conditions necessary for interlock and transition to the next cycle cannot be directly determined.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a fault diagnosis device that can quickly perform accurate fault diagnosis with less software by improving the conventional cycle diagram-based diagnosis method.

Means for Solving the Problems> In order to achieve the above object, a fault diagnosis device of the present invention diagnoses a fault in a controlled device controlled by a programmable controller based on a sequence program stored in a memory. A cycle diagram table that stores at least data regarding the cycle number, origin element, arrival end element, cycle number before and after output element 1, and reference time of each cycle constituting the sequence, and data regarding the operating conditions of each of the above-mentioned cycles. an operating condition table that stores the reference time of each cycle stored in the cycle diagram table, and a timer that measures the reference time of each cycle stored in the cycle diagram table; A calculation means that performs calculations related to failure diagnosis based on the status signal, sequence program, and timing of the above-mentioned timer, and the above-mentioned cycle diagram table showing the states of the origin and arrival end elements determined by the previous cycle for each cycle. operating condition extraction means for searching and extracting as data and storing it in the operating condition table for each cycle; and when an abnormality is detected by time monitoring of the arithmetic means, inputted via the programmable controller. A detecting means is provided for comparing the actual status signals of the originating end and reaching end elements of the controlled equipment with the data in the operating condition table for each cycle to detect a failed element.

<Operation> The cycle diagram table shows the cycle number, source end, destination end, output element, and
Data regarding previous and subsequent cycle numbers, reference time, etc. is stored. The operation condition extraction means sequentially extracts the states of the origin and destination elements determined by the previous cycle for each cycle based on the data of the cycle diagram, and extracts the extracted data for operation for each cycle. Store it in the condition table. When the sequence control starts, the calculation means determines whether each cycle ends within the above-mentioned reference time measured by the timer, that is, the origin element of the cycle is turned off, the reaching end element is turned on, and the output is determined. Whether the element is turned on or not is monitored based on the actual state signal input via the programmable controller, and when it is not, it is determined that there is an abnormality. Thus, when an anomaly is detected, the detection means determines that if only the output element corresponding to that cycle of the controlled device does not turn on, and this is not due to an anomaly in the output element itself, the anomaly is caused by that cycle. It is determined that this is not due to an abnormality, but rather to an abnormality in the elements of the previous cycle. Then, the actual state signals of the source end and destination end elements corresponding to the previous cycles inputted via the programmable controller are successively compared with the data in the above operating condition table for each cycle, and the actual state is determined. It is determined that an abnormality has occurred in a cycle in which the signal and the data in the operating condition table do not match, and the failed element is detected.

<Example> Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

FIG. 1 is a block diagram showing an embodiment of the failure diagnosis device of the present invention, and l is a controlled object that operates in sequence, having a source end such as a limit switch Ia, a destination end element, and an output element such as a coil Ib. 2 is a programmable controller that controls the controlled device 1 based on a sequence program stored in a memory (not shown); 3 is connected to the programmable controller 2;
This is a fault diagnosis device that diagnoses faults in.

The failure diagnosis device 3 includes a programmable controller 2
and an interface circuit 4 that transmits and receives data, the cycle number of each cycle composing the sequence, the primitive element,
A cycle diagram table 5 that stores data regarding the reaching end element, cycle numbers before and after the output element 9, reference time, etc.; an operating condition table 6 that stores data regarding the operating conditions of each cycle; and the cycle diagram table 5. A timer 7 measures the reference time of each cycle stored in the interface circuit 4, and status signals and sequence programs of the source end, destination end, and output element of the controlled device I inputted through the interface circuit 4, and the timer 7. C as a calculation means for performing calculations related to failure diagnosis based on time measurement
Consists of PU8.

The CPU 8 is equipped with operating condition extracting means and detecting means as software in the form of a driving program, and the former detects the state of the origin 2 reaching end element determined by the previous cycle for each cycle. The cycle diagram table 5 is searched and extracted as data, which is stored in the operating condition table 6 for each cycle.
A failed cycle is detected by comparing the actual status signals of the origin and destination elements 1a of the controlled equipment 1, which are inputted through the control unit 1, with the data in the operating condition table 6 for each cycle.

The operation of the failure diagnosis device 3 having the above configuration will be described below with reference to FIGS. 2 to 4.

FIG. 2 shows an example of a cycle diagram in which cycles constituting a sequence are sequentially arranged and described. The numbers ■, ■, ■, ... in the figure are cycle numbers indicating the operation order of each cycle, and the corresponding numbers A, E, F', ...
* indicates the output element of the cycle (see 1a in FIG. 1). Also, -C1-G, -I, ・
... is the origin element of the cycle (see 1a in Figure 1), the right end glue of each output element, H, J,... is the end element of the cycle (see 1a in Figure 1) ) are shown respectively. When one cycle is executed, the primitive element is turned off and its destination element and output element are turned on, so the primitive element is marked with a negative sign (-). Further, C and D of cycle 2 and cycle 2 indicate that they are the same element, and cycle 2 and cycle 2 are executed simultaneously and in parallel.

The operator creates data as shown in FIG. 3 for each cycle in the cycle diagram of FIG. 2, and stores this data in the cycle diagram table 5 via a keyboard (not shown) and the CPU 8. That is, regarding cycle (2), as shown in FIG. 3, cycle number 5. The following data is stored in the cycle diagram table 5: original end, arrival end M, specific output, previous cycle number 41, next cycle number 6, first cycle No. 1, end cycle No., and reference time T.

On the other hand, the operating condition extracting means searches the data in the cycle diagram table 5 and extracts, for each cycle, the states of the origin and destination elements determined by the previous cycle as shown in FIG. , this is stored in the operating condition table 6. That is, regarding cycle (■), the previous cycle is determined based on the previous cycle number in the data.

■, ■, ..., restore sequentially to the beginning of the loop ■, read out the data of the restored cycles in order of distance from the cycle ■, turn off the source end, turn on the destination end, and string -C ,D.

G, H, -I, J, . . . are obtained. In addition, if the same origin and destination end appear as in cycles ■ and ■, the contents of the later cycle ■ are given priority, the first 10 and D are deleted, and the final result is shown in Figure 4. Character string shown -〇, H, -I, J, -D,
Obtain C, -L,M. And this string is a cycle■
This data is stored in the operating condition checker 6 as data. Of course, such operation condition extraction work is performed for each cycle.

Next, when the sequence control of the controlled equipment l by the programmable controller 2 starts, the CP of the fault diagnosis device 3
U8 determines whether the cycle i ends within the reference time Ti measured by the timer 7, that is, the origin element of cycle i is off and the arrival end element is on.

Whether or not all output elements are turned on is monitored by the actual state signal of each element inputted via the programmable controller 2, and when it is not, it is determined that an abnormality has occurred. Thus, when an abnormality is detected, the detection means determines, based on the status signal, whether only the origin element of the current cycle does not turn off, only the reaching end element does not turn on, or only the output element does not turn on. If it is determined that the cycle does not turn on due to an abnormality in itself, it is diagnosed that an abnormality has occurred in the cycle itself. On the other hand, if it is determined that only the output element is not turned on due to some other abnormality, it is determined that the operating condition related to this cycle, that is, the previous cycle is abnormal. Then, the actual state signals of the source end and destination end elements corresponding to the previous cycle inputted via the programmable controller 2 are successively compared with the data in the operating condition table 6 forward for each cycle. , it is diagnosed that an abnormality has occurred in a cycle in which the two do not match.

It goes without saying that the present invention is not limited to the illustrated embodiment.

<Effects of the Invention> As is clear from the above explanation, the fault diagnosis device for controlled equipment controlled by the programmable controller of the present invention has the cycle number, original end, and destination end of each cycle in the cycle diagram table. , cycle numbers before and after output element 1,
Data related to reference time, etc. are stored, and this cycle diagram table is searched by the operating condition extracting means, and for each cycle, the origin is determined by the cycle that operates before it.

The state of the reaching end element is stored in the operating condition table, and when an abnormality is detected by the time monitoring of the calculating means, the detecting means converts the data of the operating condition table into the actual state signal of the origin end and reaching end element. Since each cycle is compared successively and an abnormality is diagnosed in a cycle where the two do not match, even if there are conditions that do not appear in the cycle diagram or complicated interlocks during the sequence, the abnormality can be detected. In addition to being able to accurately diagnose, since the diagnosis is not based on a conventional ladder diagram, there is no misdiagnosis due to human error in the ladder diagram, and with less software, it is possible to perform an economical and quick diagnosis.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the failure diagnosis device of the present invention, FIG. 2 is a diagram showing an example of a cycle diagram of sequence control, and FIG. 3 shows the data of the cycle diagram table of FIG. 1. The figure shown in FIG. 4 is a diagram showing data of the operating condition table of FIG. l...Controlled equipment, 2...Programmable controller, 3...Fault diagnosis device, 5...Cycle diagram table, 6...Operating condition table, 7...Timer, 8... CPU0 Patent applicant: Sharp Corporation and 1 other representative Patent attorney: Aohaku Ao and 1 other person

Claims (1)

[Claims] (1) A failure diagnosis device that diagnoses failures in controlled equipment controlled by a programmable controller based on a sequence program stored in a memory, which includes the cycle number, source element, and destination element of each cycle that constitutes the sequence. , a cycle diagram table that stores at least data regarding output elements, previous and subsequent cycle numbers, and reference time; an operating condition table that stores data regarding the operating conditions of each cycle; and each cycle stored in the cycle diagram table. a timer that measures the reference time of the controller, and the status signals and sequence programs of the origin, destination, and output elements of the controlled equipment inputted via the programmable controller, and calculations related to failure diagnosis based on the timing of the timer. calculation means;
For each cycle, the states of the origin and destination elements determined by the previous cycle are searched in the cycle diagram table and extracted as data, and operation condition extraction is stored in the operation condition table for each cycle. and when an abnormality is detected by the time monitoring of the calculation means, the actual state signals of the source and destination elements of the controlled equipment inputted via the programmable controller are combined with the data of the operating condition table. A failure diagnosis device that includes a detection means that compares each cycle to detect a failed cycle.