JPH0486094A - Centralized control system safety device for equipment using commercial power supply - Google Patents

Abstract

PURPOSE:To improve reliability and durability by providing a circuit which interrupts continuous response transmission that is the malfunction of a microcomputer at each equipment side using a commercial power source. CONSTITUTION:A watchdog 19 programmed to monitor the runaway of the microcomputer i.e., the continuous response transmission is provided at the microcomputer 11, and also, a reset circuit 20 which transfers the microcomputer 11 to a stoppage program when the continuous response transmission is found out by the watchdog 19 is provided. Therefore, the continuous response transmission that is the malfunction of the microcomputer can be interrupted by the circuit 20 that is hardware even when the microcomputer 11 performing the malfunction is disabled to be transferred to the stoppage program by the watchdog that is software. Thereby, it is possible to maintain the whole system in a working state even when the runaway of the microcomputer 11 of equipment occurs.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a central control system safety device for equipment using commercial power, such as forced air supply and exhaust oil heaters.

(Prior Art) As a conventional centralized control system, one is known that uses a power line or a signal line to centrally control a plurality of devices that use commercial power.

(Problems to be Solved by the Invention) In the conventional system described above, when the microcomputer of the device goes out of control, in other words, when the microcomputer sends a continuous response that is a malfunction, the communication line of the device equipped with the malfunctioning microcomputer Either a relay or the like is used to turn off the runaway, or a watchdog programmed into the microcomputer detects the runaway, and if the malfunctioning microcomputer is malfunctioning, a reset circuit is used to put it into a stop program.The former In this case, there are disadvantages such as a lack of reliability and durability as well as high costs.In the latter case, depending on the cause of the malfunction, the microcomputer cannot be transferred to the stop program, and the runaway continues, which may cause communication problems. This has the disadvantage that the entire line is monopolized and the entire system becomes unusable.

(Means for Solving the Problems) The present invention aims to solve the above-mentioned disadvantages, and includes:
A system for collectively centrally controlling a plurality of devices using commercial power using power lines or signal lines, characterized in that each device is provided with a circuit that interrupts continuous response transmission due to microcomputer malfunction.

(Function) According to the present invention having the above configuration, even if a software watchdog cannot shift a malfunctioning microcomputer to a stop program, a hardware circuit can prevent a malfunctioning microcomputer from continuing. Response transmission can be interrupted, and even if the microcomputer of the device goes out of control, the entire system can be maintained in a usable state.

(Embodiment) Next, an embodiment of the present invention will be described based on the drawings, in which the device using a commercial power source is a forced air supply/exhaust oil heater.

FIG. 1 shows a schematic explanatory diagram of a system for centrally controlling a plurality of forced air supply/exhaust oil heaters 2 using a power line 1 as a power line.

Reference numeral 3 denotes an electric light, to which power is supplied via a switchboard 4.

The switchboard 4 consists of an overall breaker 5, a blocking filter 6 for preventing control signals within the system from leaking to the outside, and a breaker 71.72 for each power line 11.12.

8 is an operating unit connected to both power lines 11 and 12,
An operation/stop command signal is transmitted to each kerosene heater 2 using a serial data communication method, and the status of each kerosene heater 2 is displayed on the monitor.

The terminal circuit of each oil heater 2 is as shown in FIG.
Coupling circuit 9, receiving circuit 10, and microcomputer 11
and a transmitting circuit 12.

The coupling circuit 9 includes a coupling capacitor 3 and a step-down transformer I.
4 and a capacitor 15, a smoothing capacitor J7, and a diode 18 for adding DC voltage.

The receiving circuit 10 is for converting, for example, a 125 KHz analog operation command signal or stop command signal sent from the operation unit 8 into a digital signal and sending it to the microcomputer 11 at the next stage.

The microcomputer 11 is provided with a programmed watchdog 19 for monitoring its runaway, in other words, continuous response transmission, and when continuous response transmission is detected by the watchdog 18, the microcomputer A reset circuit 20 is provided for transitioning the program 11 to the stop program.

The transmission circuit 12 receives as input signals 4 a digital response transmission signal from the microcomputer 11 and a digital signal from an oscillator 28 of, for example, 1.25 KHz for synchronizing with the command signal from the operating unit 8. AND
a circuit 21, an amplification circuit 22 that amplifies and transmits an output signal from the AND circuit 21, and the microcomputer 1.
When capacitor 1 goes out of control and the response transmission signal continues, capacitor 2
3 is charged and consists of a pump-up circuit 24 which stops transmission from the amplifier 22.

Next, the operation of the system safety device having the above configuration will be explained.

Normally, the microcomputer 11 of each kerosene heater 2 processes the operation command signal or stop command signal sent from the operation unit 8 via the power line 1, the coupling circuit 9, and the receiving circuit 10. Each oil heater 2 depending on the content
is started or stopped, and the processing contents of the microcomputer 1 are sent as a response to the operation unit 8 via the AND circuit 21 of the transmission circuit 12, the amplifier circuit 22, the coupling circuit 9, and the power line 1, and the operation is performed. The status of each oil heater 2 is displayed on the unit 8 on a monitor.

However, the microcomputer 11 of the oil heater 2 consisting of
In an abnormal situation where the microcomputer 11 goes out of control and responds continuously, the software watchdog 19 may not be able to shift the malfunctioning microcomputer 11 to the stop program.

In this case, the capacitor 23 of the transmitting circuit 12 is charged, and the transistor 2L 27 of the amplifier circuit 21 is turned off via the NOT circuit 25 of the pump-up circuit 24.
Transmission from the amplifier circuit 22 is interrupted.

As a result, since there is no response from the terminal circuit including the malfunctioning microcomputer 11, the operation unit 8 determines that only that terminal circuit is abnormal, and operates other kerosene heaters other than the kerosene heater 2 having this terminal circuit. In the second operation, stop control is continuously performed.

In addition, although the above-mentioned Example is a case where the equipment using commercial power supply is a forced air supply/exhaust type oil heater, it is not limited to this.

Incidentally, although the above-mentioned embodiment uses a light line as a power line, a similar safety device can also be formed using a signal line.

(Effects of the Invention) As described above, according to the present invention, since a circuit is provided on each device that uses a commercial power supply to interrupt continuous response transmission, which is a malfunction of the microcomputer, if the microcomputer transmits a continuous response, the malfunction can be prevented. Compared to the conventional system safety device, which disconnects the communication line of equipment equipped with a microcomputer using a relay or the like, it has superior reliability and durability, and has the effect of lower cost. This has the effect of reducing the failure rate compared to the conventional system safety device that causes the microcomputer to enter a stop program.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing an example of the implementation of the present invention when the device using commercial power is a forced air supply/exhaust oil heater;
FIG. 2 is a terminal circuit diagram of each oil heater. 1.11.12...Electric light line (power line) 2...Forced air supply/exhaust oil heater (equipment using commercial power supply) 3...Light light 8...Operation unit 11...Microcomputer] 2 ...Transmission circuit 19...Watchdog

Claims (1)

[Claims] A system for centrally controlling a plurality of devices that use commercial power using power lines or signal lines, characterized in that each device is equipped with a circuit that interrupts continuous response transmission due to microcomputer malfunction. A central control system safety device for equipment that uses power.