JPS60224349A - Detection for power failure - Google Patents

Abstract

PURPOSE:To obtain a compact and low-cost power failure detector without degrading the precision of power failure detection by writing and reading repeatedly data having a specific pattern for power failure detection in a data gathering system which is not protected from power failure. CONSTITUTION:In the monitor and control system where a master station 1 gathers data of slave stations 2-n, each slave station which is triggered by polling from the master station 1 reads data having a specific pattern for power failure detection which is written in a memory and transmits this data to the master station and writes data and repeats this operation. If power failure occurs between polling and polling, power failure information is transmitted to the master station, and the slave station writes said data again. If power failure occurs in the slave station at the polling time, data for power failure detection is not transmitted to the master station, and the master station finds the occurrence of power failure.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a power outage detection method in a data collection system that is not uninterrupted.

(Background technology) Conventionally, in data collection systems that are not uninterrupted, if a power outage occurs between one data collection time and the next data collection time, the reliability of the data collected before the power outage is extremely low. turn into. For this purpose, it is necessary to make the data collection device uninterrupted or to provide a device with a power failure detection function outside the device. As a result, the cost of the entire system increases, resulting in a large-scale device.

(Problems to be solved by the invention) The present invention solves these problems and writes a specific pattern of data for power outage detection into a memory within a data processing system without using an uninterruptible device such as a battery or an external device. It is an object of the present invention to provide a compact and low-cost device using a method of detecting the presence or absence of a power outage based on whether or not a specific pattern of data for power outage detection is read out when attempting to read out the data.

(Detailed Description of the Invention) FIG. 1 is a diagram showing a sequence in an embodiment of the present invention. In the figure, first, when the power is turned on by a controller such as a CPU, two operations are performed: reading (memory read) and writing (data write) a specific pattern of data for power outage detection in the power outage detection memory area. This is repeated at regular intervals (T) using a timer or the like. In the event of a power outage, control operations including the above operations are stopped.

After the power is restored, the controller turns on again, first performs memory clearing, and then starts control operations again including periodic operations of memory read and data write. Therefore, after the power is restored, the controller performs a memory read operation that is performed after the first period T after memory clearing. However, since the memory has already been cleared, the specific pattern data for power outage detection is gone.
This means that it cannot be read when reading memory. Therefore, it is possible to detect that a power outage has occurred at this point. After that, the controller writes data, so that a specific pattern of data for power failure detection is written into the power failure detection memory area again, and a state becomes possible where power failure can be detected.

FIG. 2 is a block diagram showing another embodiment of the present invention. In the figure, l is a monitoring station (hereinafter referred to as a master station), which gives an instruction (hereinafter referred to as a trigger) to each slave station in order to monitor the presence or absence of a power outage in the monitored stations (hereinafter referred to as slave stations) 2 to n. 2 to n are monitored stations (
A slave station (hereinafter referred to as a slave station) performs memory read and data write operations upon receiving a trigger when polling from the master station I.

In this embodiment, instead of installing a timer inside the core controller and performing periodic operations of memory read and data write in the previous embodiment, instructions are given from a remote location to monitor the presence or absence of a power outage. It is.

To explain in detail, as shown in FIG. 2, the master station 1 and the slave station 2
~n, and serves as a monitoring control system that collects data of slave stations.

Each slave station 2 that received a trigger during polling from the master station 1
~n, the controller reads the memory. If a power outage occurs between polls, power outage information is sent to the master station I. Thereafter, each slave station 2 to n performs data write again to write a specific pattern of data for power failure detection. Therefore, when polling, the slave station performs memory reads and data writes and sends them to the master station, so if there is a power outage, data for power failure detection will not be sent to the master station, and the master station will I understand that there was. Therefore, even a master station located at a remote location can monitor the presence or absence of a power outage in a slave station.

(Effects of the Invention) As described above, according to the present invention, power outage detection is achieved by repeatedly writing and reading a specific pattern of data for power outage detection in a data collection system that is not uninterrupted. A compact, low-cost device can be provided without compromising accuracy. Furthermore, since there is no need for uninterrupted power outage and the controller only needs to have standard functions, it can be used for power outage detection in remote monitoring and control equipment.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a sequence in one embodiment of the invention, and FIG. 2 is a block diagram showing another embodiment of the invention. 1-111 monitoring station, 2~n-111 monitored station. Patent applicant: Oki Electric Industry Co., Ltd. Patent application agent: Megumi Yamamoto

Claims (2)

[Claims] (1) In a power outage detection method for a data collection device that has not experienced a fi power outage, it is possible to perform both a read operation from a memory area for power outage detection and a writing operation of a specific pattern of data for power outage detection at a predetermined period. A power outage detection method characterized in that when the data match, it is determined that there is no power outage, and when they do not match, it is determined that there has been a power outage during the predetermined time period. (2) The power failure detection method according to claim 1, wherein the read operation and the write operation are performed by an instruction from an outside. −