JPH04181303A - Detecting method for momentary power failure time of programmable controller - Google Patents

Abstract

PURPOSE:To enable a user to recognize a momentary power failure time by measuring the time from when a power unit has a power supply break on its primary side to the time of a system reset stop, storing the measured time as the momentary power failure time in a memory means, and reading it out of the memory means and detecting the momentary power failure time. CONSTITUTION:When the secondary-side voltage drops below a specific value, the system is reset and stopped and the time from the power break of the primary side of the power unit 7 to the system reset stop is measured. This measured time is stored as the momentary power failure time in the memory means 5 and then read out of the memory means 15 to detect the momentary power failure time. Thus, the programmable controller 11 itself automatically measures and stores the momentary power failure time in the memory means 15, so even if the system is reset and stopped when the secondary voltage drops larger than a specific time below a rate voltage, the user can exactly recognize the momentary power failure time without trouble by reading the memory means 15.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a programmable controller used for various sequence controls, and particularly relates to a method for detecting instantaneous power outage time for detecting the time from the generation of 1JIIT to the occurrence of a system reset stop. It is something.

(Prior Art) Programmable controllers, especially programmable logic controllers using CPUs, which can efficiently perform various sequence controls in various factory automation etc. using changeable programs, have been well known and widely used. It is widespread.

In a programmable controller, when the system program is running, the CPU of the programmable controller
If the power supply to the memory is stopped, there is a risk that the system progera j1 and other memory contents will be destroyed.
Is it necessary to perform a system reset stop before stopping power supply to the memory?

In general, programmable controllers are powered by a commercial AC power source, and are operated by being supplied with a predetermined DC secondary voltage from a power supply device including a transformer. Even if voltage is no longer applied, that is, even if a power outage occurs, the secondary voltage does not disappear instantly, so the CPU of the programmable controller
, it is possible to perform a system reset stop prior to stopping power supply to the memory.

Even if a power outage occurs, the secondary side voltage does not disappear instantly, so if the power outage is instantaneous within the secondary voltage holding time, the secondary side voltage will not disappear even if a power outage occurs. Since it is continuously held, there is no need to reset and stop the system at this time, that is, when there is a momentary power outage.

For this reason, in a programmable controller such as a "double series", the power outage time is measured by a hardware or software timer, and the power outage time is set to a predetermined value, that is, the instantaneous power outage time (system reset stop tolerance). time), the system does not reset and stop, but when the power outage time or instantaneous power outage time (instantaneous power outage time) is exceeded, the system reset and stop is performed to prevent system reset -1 from occurring as much as possible. It is like that.

(Problem to be Solved by the Invention) Even if a power outage occurs, the time during which the secondary side voltage is maintained after that, that is, the secondary side voltage holding time, is determined by the I10 unit (input/output crab unit) connected to the programmable controller.
10m5ec ~ 200m5e depending on the load etc.
It changes to c.

On the other hand, in the case where the power outage time is measured by a hardware timer, the instantaneous power outage time is fixed and cannot be changed, and the instantaneous power outage time is set to a short value in consideration of safety, for example, 1Qmsec to 40m5ec. is set to

In this case, the system reset stop may be performed even though the secondary voltage is maintained at the time of power interruption and there is no need to perform the system reset stop. When a system reset stop is performed, it takes time to reboot the system, and depending on the plant to be controlled by the programmable controller, the plant may return to its initial operation and malfunction.

In the case where the power outage time is measured using a software timer, the instantaneous power outage time can be changed and adjusted by the user, but this setting is done arbitrarily based on the user's experience, etc., and the optimum setting for this is required. This takes time and may result in incorrect settings. If the instantaneous power outage time is erroneously set to be longer than the appropriate value, there is a risk that the secondary voltage will disappear before the system reset is stopped, and the memory contents will be destroyed.

In view of this, it has been considered to monitor the secondary voltage and perform a system reset stop when the secondary voltage drops to a predetermined value or more below the rated voltage. In this case, there is no need to set the instantaneous power outage time in advance, but the user cannot recognize the instantaneous power outage time.

The present invention has been made in view of the above-mentioned problems, and provides an instantaneous system reset in a programmable controller that performs a system reset stop when the secondary voltage drops to a predetermined value or more than the rated voltage. It is an object of the present invention to provide a method for detecting instantaneous power outage time of a programmable controller by which the power outage time can be recognized by the sound used.

(Means for resolving the problem) According to the present invention, the above-mentioned object is to provide a method for detecting instantaneous power outage time of a programmable controller that operates by receiving a predetermined secondary voltage from a power supply device including a transformer. In this case, a system reset stop is performed when the secondary side voltage decreases beyond a predetermined value, and the time from when the power cut occurs on the primary side of the power supply device to when the system reset stop occurs is actually measured. This is achieved by a method for detecting instantaneous power outage time for a programmable controller, which is characterized in that the instantaneous power outage time is detected by storing the time that has occurred as the instantaneous power outage time in a memory means and reading it from the memory means.

(Function) According to the instantaneous power outage time detection method for a programmable controller according to the present invention, the instantaneous power outage time is automatically measured by the programmable controller itself and stored in the first stage of memory, and by reading from the first stage of the memory, the user can instantly Accurately recognize power outage time.

(Example) The present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a block diagrammable controller used to implement the instantaneous power failure time detection method according to the present invention.

The programmable controller includes a CPU device 1 as a main body of the programmable controller, a power supply device 3, and an I/O device.
10 units and 5.

The CPU device 1 includes a CPU 7, a system memory 9 that stores system programs, etc., a user program memory 11 that stores user programs, and an I10 memory]3
, a work memory 15, a clock generation stage 17, and a C
A reset circuit 19 that outputs a system I (reset)/stop command to the PU 7, a momentary power failure detection circuit 21, an interface 23, and an internal bus 25 that connects these to each other.
and h'.

The power supply device 3 has a well-known structure including a transformer, one stage rectifier, etc., and is supplied with an AC voltage from a commercial AC power source as a secondary power source, and a predetermined DC voltage as a secondary side voltage. A voltage, for example, 5 cm of direct current is applied to the CPU device 1. In addition, the power supply device 3 sends a signal indicating that the primary power supply has been cut off to the instantaneous power failure detection circuit 2 of the CPU device 1.
It is designed to output to 1.

The I10 unit 5 is connected to the interface 23 of the CPU device 1 via an external bus 27.

The reset circuit 19 monitors the secondary voltage, and outputs a system reset/reset stop command to the MPU 7 when the secondary voltage drops to a predetermined value or more below the rated voltage.

The instantaneous power failure detection circuit 21 monitors the interruption of the primary power source of the power supply device, that is, the occurrence of a power outage, and outputs an instantaneous power outage interrupt command to the CPU 7 when a power outage occurs.

When the CPU 7 accepts the instantaneous power failure interrupt command, it executes the instantaneous power failure interrupt processing routine. is actually measured and stored in the momentary power failure time=1 measured value storage area of the work memory 15.

FIG. 2 shows an example of a momentary power failure interrupt processing routine.

In this case, first, in step 10, the measured value Tn is
Then, in step 20, the software determines whether a change has occurred in the lm5ec timer. If a change occurs in the 1m5ec timer, the measured value Tn is increased by 1 m5ec. Next, the measured value Tn is stored in the instantaneous power failure time measured value storage area of the work memory]5.

The instantaneous power failure time measurement value storage area of the work memory 15 is configured to individually store a plurality of, for example, four, measurement values T1 to T4.

1- The instantaneous power failure interrupt processing routine as described above is forcibly terminated by system reset, and the measured value Tn at this point is retained in the instantaneous power failure time 51 measurement value storage area of the work memory 15. =1 measurement of the time measurement value storage area (i'jTn is the actual measurement value of the time from when the power cut occurs until the system reset stop is executed.

When the power is restored and the system reset is canceled, the third
The general program as shown in the figure is executed,
Power-on processing is performed in step 100, and then, in step 200, main processing as a programmable controller is performed.

FIG. 4 shows a power-on processing routine, in which first, in step 110, measured values T1 to T4 are respectively read out from the instantaneous power failure time measured value storage area of the work memory 15, and then In step 120, the measured value T
The representative instantaneous power outage time (representative instantaneous power outage time) T is determined by majority vote from 1 to T4. This is the measured value T1
~ If there is an incorrect value within T4, it is removed by majority voting processing to obtain a normal value. In this case, majority voting processing means to select the most common measured value Tn among the measured values Tl-74. This is a process of setting the value to a normal value (representative value). This normal value is stored as the representative instantaneous power outage time T in the instantaneous power outage time storage area of the I10 memory 13.

The representative instantaneous power outage time T stored in the instantaneous power outage time storage area of the I10 memory 13 can be freely read out by a user's external command. This allows the user to recognize the instantaneous power outage time.

(Effects of the Invention) As understood from the above explanation, according to the instantaneous power outage time detection method for a programmable controller according to the present invention,
The instantaneous power outage time is automatically measured by the programmable controller itself and stored in the memory means. By reading the information, the user can accurately recognize the instantaneous power outage time without any trouble.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a programmable controller used to implement the instantaneous power outage time detection method according to the present invention, and FIG. 2 is a block diagram showing an embodiment of the programmable controller used to implement the instantaneous power outage time detection method according to the present invention. FIG. 3 is a flowchart showing an example of a general program of a programmable controller; FIG. 4 is a flowchart showing an example of a programmable controller power-on processing routine in which the instantaneous power failure time detection method according to the present invention is implemented. It is a flowchart. 1... CPU device 3... Power supply device 5... I10 unit 7... CPU 9... System memory 11... User program memory 13... I10 memory 15... Work memory 17...・Clock generation means 19 ・Reset circuit 21 ・Momentary power failure detection circuit 23 ・Interface 25 ・Internal bus 27 ・External bus Patent applicant OMRON Co., Ltd. Agent Patent attorney Sei Wada Rule 11:21?1 Power source Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. In a method for detecting instantaneous power outage time of a programmable controller that operates by being supplied with a predetermined secondary voltage from a power supply device including a transformer, the secondary voltage exceeds a predetermined value. When the voltage decreases, a system reset stop is performed, the time from the occurrence of a power cut on the primary side of the power supply device to the system reset stop is actually measured, and the measured time is stored in a memory means as an instantaneous power outage time. A method for detecting instantaneous power outage time for a programmable controller, characterized in that the instantaneous power outage time is detected by reading out from the memory means.