JP2527803B2 - Fault diagnosis device - Google Patents

Description

The present invention relates to a failure diagnosis device for diagnosing a failure of a controlled device controlled by a programmable controller based on a sequence program stored in a memory.

<Prior Art> Conventionally, as a failure diagnosis apparatus of this type, for example, Japanese Patent Laid-Open No.
There is one described in Japanese Patent Publication No. 148178. This fault diagnosis device is added to a programmable controller that controls a controlled device having input and output elements based on a sequence program stored in a memory, and a cycle counter that counts a cycle number according to an operation step of the controlled device. And a computer that detects an abnormality by monitoring the cycle number of this cycle counter and searches the sequence program for the cause of the abnormality and diagnoses it.
Then, this computer finds a failure factor from the signal states of the output element and the reaching end element of the operation step corresponding to the cycle number at the time of occurrence of an abnormality by the software, and the program corresponding to this failure factor is selected from the sequence program. At the same time as finding, the found program is simulated to find the operation switching failure condition of the output element, and the failure condition is output to the alarm display section.

<Problems to be Solved by the Invention> However, in the above-described conventional failure diagnosis device, the computer searches for a program corresponding to the failure factor from the sequence program described in detail at the level of the ladder diagram (expansion connection diagram), Since the program found is sequentially simulated to find the operation switching failure condition, there is a drawback that the software for that is huge and the diagnosis takes a long time. Further, if the sequence program to be stored in the memory of the programmable controller, that is, the ladder diagram is erroneously input, there is a drawback in that the failure factor cannot be accurately searched and correct failure diagnosis cannot be performed.

On the other hand, as a simple fault diagnosis method, there is a method of performing time monitoring based on a cycle diagram in which the cycle number, original end, reaching end, output element, reference time, etc. of each cycle constituting a sequence are sequentially described. In this cycle diagram, the conditions required for interlocking and transition to the next cycle cannot be directly understood, so that there is a drawback that the accuracy of diagnosis deteriorates.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a failure diagnosing device capable of quickly performing an accurate failure diagnosis with a small amount of software by improving a conventional diagnosis method based on a cycle diagram.

<Means for Solving the Problems> In order to achieve the above object, the failure diagnosis apparatus of the present invention is
A fault diagnosis device for diagnosing a fault in a controlled device controlled by a programmable controller based on a sequence program stored in a memory, the cycle number of each cycle constituting a sequence, a source end element, a reaching end element, an output element. , A cycle diagram table that stores at least data related to cycle numbers before and after, and reference time, an operation condition table that stores data related to operation condition of each cycle, and a reference time of each cycle stored in the cycle diagram table A timer for counting the time, a source and a destination of the controlled device input via the programmable controller, a state signal of an output element and a sequence program, and an arithmetic means for performing an operation relating to a failure diagnosis based on the timing of the timer. , Before each cycle An operating condition extracting means for searching the cycle diagram table for extracting the states of the original end element and the reaching end element, which are determined by the cycle to be created, as data, and storing the data in the operating condition table for each cycle, and the computing means. When an anomaly is detected by the time monitoring of, the anomaly stored in the operating condition table is the actual state signal of the original end and reaching end elements of the controlled device input via the programmable controller. Compared with the cycle data, only the raw end element is not turned off,
If it is determined that only the reaching element does not turn on or that only the output element does not turn on due to its own abnormality, it is diagnosed that an abnormality has occurred in the cycle itself, while only the output element turns on due to another abnormality. If it is determined that the previous cycle is abnormal, it is determined that the cycle is abnormal, and the actual state signals of the original end and reaching end elements corresponding to the previous cycle input through the programmable controller are used as the operating conditions. A detection unit is provided that sequentially compares the data in the table with each cycle forward and diagnoses that an abnormality has occurred in a cycle in which the two do not match.

<Operation> The cycle diagram table stores data on the cycle number of each cycle constituting the control sequence, the original end, the reaching end, the output element, the preceding and succeeding cycle numbers, the reference time, and the like. The operating condition extracting means sequentially extracts the states of the original end element and the reaching end element, which are determined by the cycle that operates before that, based on the data in the cycle diagram table, and operates the extracted data for each cycle. Store in the condition table. When the sequence control starts, the arithmetic means determines whether or not each cycle ends within the reference time measured by the timer, that is, the original end element of the cycle is turned off, the reaching end element is turned on, and the output element is turned on. Whether or not is turned on is monitored based on the actual state signal input via the programmable controller, and when it is not, an abnormality is detected. When the computing means detects an abnormality, the detecting means compares the actual state signals of the original end and the arriving end element of the controlled device at that time with the data of the cycle stored in the operation condition table, and the original end is detected. If it is determined that only the element does not turn off, only the reaching end element does not turn on, or only the output element does not turn on due to its own abnormality, it is diagnosed that an abnormality has occurred in the cycle itself, while the output element If it is determined that only one of them is not turned on due to another abnormality, it is determined as an abnormality in the previous cycle and the actual of the original end and reaching end elements corresponding to the previous cycle input via the programmable controller The state signal of is compared with the data of the operating condition table forward for each cycle, and it is diagnosed that an abnormality has occurred in a cycle in which the two do not match.

<Examples> Hereinafter, the present invention will be described in detail with reference to illustrated examples.

FIG. 1 is a block diagram showing an embodiment of the failure diagnosis device of the present invention, in which 1 is a controlled device that has a source end such as a limit switch 1a, a reaching end element, and an output element such as a coil 1b to perform a sequence operation. A device, 2 is a programmable controller for controlling the controlled device 1 based on a sequence program stored in a memory (not shown), and 3 is a failure diagnosis device connected to the programmable controller 2 for diagnosing a failure of the controlled device 1. is there.

The failure diagnosis device 3 includes an interface circuit 4 for transmitting and receiving data to and from the programmable controller 2, a cycle number of each cycle forming a sequence, a source end element, a reaching end element, an output element, preceding and following cycle numbers, and data relating to a reference time. And the like, a cycle diagram table 5 for storing the above, an operation condition table 6 for storing data relating to the operation condition of each cycle, a timer 7 for measuring the reference time of each cycle stored in the cycle diagram table 5, From the CPU 8 as an arithmetic means for performing an arithmetic operation relating to a failure diagnosis based on the original signal, the arriving signal of the controlled device 1 input via the interface circuit 4, the state signal of the output element and the sequence program, and the timing of the timer 7. Become.

The CPU 8 is provided with operating condition extracting means and detecting means as software in the form of a driving program. In the former, the states of the original end element and the reaching end element which are determined by the cycle operating before each cycle are described above. While the cycle diagram table 5 is searched and extracted as data and stored in the operating condition table 6 for each cycle, the latter is the programmable controller 2 when the CPU 8 detects an abnormality by time monitoring of each cycle. Original end and reaching end element 1a of controlled device 1 input via
The actual state signal of is compared with the data of the operating condition table 6 for each cycle to detect the failed cycle.

The operation of the failure diagnosis device 3 having the above configuration will be described with reference to FIG.
Next, referring to FIG.

FIG. 2 shows an example of a cycle diagram in which the cycles forming the sequence are sequentially arranged and described. The numbers in the figure ... Cycle numbers indicating the operation order of each cycle, and the corresponding A, E, F, ... Indicate output elements of that cycle (see 1b in FIG. 1). . Further, -C, -G, -I, ... At the left end of each output element is the original end element of the cycle (see 1a in FIG. 1), and D, H, at the right end of each output element.
J, ... are the end elements of the cycle (see 1a in Fig. 1)
Are shown respectively. When one cycle is executed, the original end element is turned off, and the arrival element and the output element are turned on. Therefore, the original end element is given a negative sign (-).
Further, the cycle and the C and D of the cycle indicate that they are the same element, and the cycle and the cycle are executed concurrently in parallel.

The operator creates data as shown in FIG. 3 for each cycle of the cycle diagram of FIG. 2, and this data is sent to the cycle diagram table 5 via the keyboard (not shown) and the CPU 8.
To memorize. That is, regarding the cycle, the third
As shown in the figure, the data of cycle number 5, source end-L, reaching end M, output K, previous cycle number 4, next cycle number 6, start cycle no, end cycle no, and reference time T ₅ is the cycle diagram. Stored in Table 5.

On the other hand, the operating condition extracting means retrieves the data in the cycle diagram table 5 and extracts the states of the original end and the reaching end elements determined by the cycle operating before each cycle as shown in FIG. , Are stored in the operating condition table 6. That is, regarding the cycle,
For the previous cycle number in the data, list the previous cycles up to the beginning of the loop, read the data of the listed cycles sequentially in the order distant from the cycle, turn off the original end, and set the reaching end. It is turned on to obtain the character strings -C, D, -G, H, -I, J, ... When the same original end and reaching end appear as in a cycle, the contents of the subsequent cycle are given priority, the first -C and D are deleted, and the character string shown in Fig. 4 is finally given. −G, H,
-I, J, -D, C, -L, M are obtained. Then, this character string is stored in the operation condition table 6 as cycle data. Of course, such operation condition extraction work is performed for each cycle.

Next, when the sequence control of the controlled device 1 by the programmable controller 2 is started, the CP of the failure diagnosis device 3 is started.
U8 determines whether or not the cycle i ends within the reference time Ti measured by the timer 7, that is, whether or not the original end element of the cycle i is off, the reaching end element is on, and the output element is on. This is monitored by an actual state signal of each element input 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, that only the original end element of the current cycle is not turned off, only the reaching end element is not turned on, or only the output element is itself turned on. If it is determined that the power will not be turned on due to the abnormal condition, the abnormality is diagnosed in the cycle itself. On the other hand, when it is determined that only the output element is not turned on due to another abnormality, it is determined that the operation condition regarding this cycle, that is, the abnormality of the cycle before that. Then, the actual state signals of the original end and reaching end elements corresponding to the previous cycle input via the programmable controller 2 are sequentially compared with the data of the operation condition table 6 forward every cycle, It is diagnosed that an abnormality has occurred in a cycle in which the two do not match.

Needless to say, the present invention is not limited to the illustrated embodiment.

<Effects of the Invention> As is apparent from the above description, the failure diagnosis device for controlled equipment controlled by the programmable controller of the present invention has the cycle number, the original end, and the arrival end of each cycle in the cycle diagram table. , Output element, preceding and following cycle numbers, reference time, and other data are stored, and the operation condition extraction means searches this cycle diagram table to determine the original end and arrival end elements for each cycle. The state of is stored in the operating condition table, and when an abnormality is detected by the time monitoring of the calculating means, the detecting means outputs the actual state signals of the original end element and the reaching end element to the data of the operating condition table for each cycle. Since it is diagnosed that an abnormality has occurred in a cycle in which the two do not match by successive comparison, the cycle Abnormal parts can be accurately diagnosed even if there are conditions or complicated interlocks that are not shown in the diagram, and since it is not based on the conventional ladder diagram diagnosis, there is no misdiagnosis due to the input mistake of the ladder diagram, and the software A small number, excellent in economic efficiency, and capable of quick diagnosis. In addition, since the actual state signal and the normal data stored in advance are sequentially compared from the cycle in which the abnormality is detected to the preceding cycle, the abnormality is diagnosed in the cycle in which the two do not match, so it is better than other diagnostic methods. Therefore, it is possible to make a diagnosis by storing only the data relating to the cycle number, the source end element, the reaching end element, the output element, the preceding and following cycle numbers, and the reference time in the cycle diagram table. The capacity can be increased.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the failure diagnosis apparatus of the present invention, FIG. 2 is a diagram showing an example of a sequence control cycle diagram, and FIG. 3 is data of the cycle diagram table of FIG. 4 and FIG. 4 are views showing the data of the operation condition table of FIG. 1 ... Controlled device, 2 ... Programmable controller, 3 ... Failure diagnosis device, 5 ... Cycle diagram table, 6 ... Operating condition table, 7 ... Timer, 8 ... CP
U.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-59-218523 (JP, A) JP-A-1-38809 (JP, A) JP-A-63-303407 (JP, A) JP-A-1- 15809 (JP, A)

Claims (1)

(57) [Claims] 1. A failure diagnostic device for diagnosing a failure of a controlled device controlled by a programmable controller based on a sequence program stored in a memory, wherein the cycle number of each cycle constituting a sequence, a source end element, and an arrival. A cycle diagram table that stores at least data on end elements, output elements, cycle numbers before and after, reference time, an operation condition table that stores data on operation conditions of each cycle, and a cycle diagram table stored on the cycle diagram table A timer for counting the reference time of each cycle, a source signal of the controlled device input via the programmable controller, a reaching end, a status signal of the output element and a sequence program, and a calculation for failure diagnosis based on the timing of the timer. And the calculation means for each cycle And an operating condition extracting means for extracting the states of the original end and the reaching end elements determined by the cycle operating before that as the data by searching the cycle diagram table and storing the data in the operating condition table for each cycle. , When an abnormality is detected by the time monitoring of the calculating means,
The actual state signals of the source and destination elements of the controlled device, which are input via the programmable controller, are compared with the cycle data in which an abnormality is detected stored in the operating condition table, and the source element is compared. If it is determined that only the reaching end element does not turn on, or that only the output element does not turn on due to its own abnormality, it is diagnosed that an abnormality has occurred in the cycle itself, while only the output element If it is judged that the other cycle does not turn on, it is judged as an abnormality in the previous cycle, and the actual elements of the original end and reaching end corresponding to the previous cycle input via the programmable controller are actually detected. The status signal is successively compared with the data in the above operating condition table forward for each cycle, and an error occurs in the cycle where the two do not match. Fault diagnosis apparatus having a detecting means for diagnosing that.