JPS61813A - Deciding system for faulty area of sequence controller - Google Patents

Abstract

PURPOSE:To attain a highly general-purpose system for decision of a faulty area with low cost by collating the correspondence between an action signal and a state detecting signal with the stored data for each controlled system when a fault is produced for decision of the fault. CONSTITUTION:The correspondence of variation between the action signal of a controlled system 2 and the state detecting signal of a detector 3 is first stored in a memory 6 in a normal action mode. Then the generation of a fault is first monitored when an automatic continuous operation is started. This operation is discontinued in case a cycle time-over state is produced owing to some fault. Then the correspondence between the action signal and the state detecting signal is checked for each controlled system 2 and then collated with the stored data. When a correspondence having no coincidence with the stored data is detected, it is decided that a fault occurs to the combination between the controlled system 2 and the detector 3. This decision is displayed at a display device 4.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a sequence control device used in industrial equipment.

(b) Conventional technology In equipment that performs sequence control, attempts have been made to automatically determine the problem location when an abnormality occurs.
Examples thereof can be found in Japanese Patent Application Laid-open No. 53-60466 or Japanese Patent Application Laid-Open No. 54-140072. The method described in Japanese Unexamined Patent Publication No. 53-60466 is an example of the use of a so-called watchdog timer, in which the time required for each step of a sequence is monitored by a timer, and if the set time is exceeded, that sequence step is It is determined that a problem has occurred. However, basically only sequence steps can be identified by this method, and in order to find the problem location, it is necessary to further compare the control objects involved in that step. Therefore, the work of creating a comparison table and comparing it with this table is added. Although it is possible to store a comparison table in electronic memory and automatically display the sequence steps in question and the associated control objects, this does not eliminate the effort of inputting them into memory. Japanese Unexamined Patent Publication 1973-14
The method described in the No. 0072 publication is different from this, in that before each sequence step is executed, it is checked whether the conditions that make the execution possible are in place.

Therefore, if there is an abnormality, it can be detected immediately and with high accuracy, but there is a drawback that it requires a great deal of cost to create a failure detection program that is commensurate with the number of sequence steps and to equip a memory to store it.

(c) Purpose of the Invention It is an object of the present invention to provide a failure location determination method that can be prepared at a relatively low cost and is highly versatile.

(d) Configuration of the Invention When the state of the controlled object changes, the state detection signal issued by the detector monitoring its operation also changes. In the present invention, when an operation signal is given to a single controlled object (or when it is turned OFF), if there is a detector whose status detection signal changes accordingly, that controlled object and the detector are associated. The correspondence between the changes in the operating signal and the state detection signal is written into the storage device.Then, when an abnormality occurs, the correspondence between the operating signal and the state detection signal for each controlled object is compared with the stored data, and if it does not match the data. If this is discovered, it is determined that there is a failure in the controlled object or the detector.

(E) Embodiment In FIG. 1, (1) is an operation command means for issuing a sequence execution command, which can be constituted by a switch or a keyboard. (2) is a controlled object such as a motor, solenoid, or air cylinder. (3) is a detector that monitors the operation of the controlled object (2), and (4) is a display device that displays various commands and operating states. (5> is an arithmetic processing device that arithmetic processes the sequence execution command from the operation command means (1) and the state detection signal from the detector (3) and outputs an operation signal to the controlled object (2>).Arithmetic processing Device 5) includes a storage device (
6) is included. (7) and (8) are input devices that serve as an interface between the operation command means (1), the detector (3), and the arithmetic processing unit (5), and (9) and (10) are the controlled objects (2).
and an output device that serves as an interface between the display device (4) and the arithmetic processing device (5).

Next, the mechanism of the fault location determination method using this device will be explained. First, for each of the controlled objects (2), a signal is given that allows only that controlled object to operate. Such a signal is generated by giving a mold movement command from the operation command means (1). When the controlled object (2) operates thereby, the state detection signal of the related detector (3) changes. In the example shown in the figure, limit switch A and limit switch B are arranged for one controlled object (2), and when the operation signal to controlled object (2) is turned ON, the limit switch is switched on after a short time delay. The state detection signal of A is OFF, and the state detection signal of limit switch B is ON.When the operation signal is OFF, the state detection signal is 0N-O.
The F amount relationship is reversed. In this way, the correspondence relationship between changes in the operating signal and the state detection signal during normal operation is stored in the storage device (6). Perform this work for all controlled objects (2). Now, when continuous automatic operation starts,
First, establish a system to monitor the occurrence of failures. This can be achieved, for example, by providing a watchdog timer, which does not need to check side sequence steps, but rather monitors the cycle time of the entire sequence. If the cycle time is over due to some kind of abnormality, stop the operation, check the correspondence between the operation signal and the state detection signal for each controlled object (2), and compare it with the stored data. Go.

As a result, when a correspondence relationship that does not match the stored data is found, it is determined that a failure has occurred in the combination of the controlled object (2) and the detector (3), and a display device t(
4>.

(F) Effects of the Invention The present invention prepares for a failure location determination method by storing the correspondence between changes in operating signals and state detection signals for each controlled object as data. No matter how many devices you use, you can prepare as many storage devices as you want to control, which saves time and storage space.Also, there is no need to create failure location determination programs for each type of device. According to the present invention, a determination method that can immediately identify a failure location can be provided at a relatively low cost.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing an example of the relationship between an operation signal and a state detection signal. <2) Controlled object, <3) Detector (1) Operation command means, (5) Arithmetic processing unit, (6) Storage device.

Claims (1)

[Scope of Claims] 1) A controlled object, a detector that detects the operating state of the controlled object, and an operation command means that issues a sequence execution command;
and an arithmetic processing device that arithmetic processes the sequence execution command and the state detection signal from the detector and outputs an operation signal to the controlled object, when the controlled object is in normal operation. Correspondence data between the operation signal and the state detection signal from the detector is stored in a storage device, and when an abnormality occurs, the correspondence relationship between the operation signal issued at that time and the state detection signal from the detector is stored in the stored data. A failure location determination method for a sequence control device, characterized in that a failure location is determined based on whether the comparison matches or does not match.