JPH0277449U - - Google Patents

Description

[Brief explanation of drawings]

FIG. 1 is a block diagram of the safety circuit of the combustion control device of the present invention. Figure 2 is a block diagram of the safety circuit of a conventional combustion control device. FIG. 3 is an operation timing diagram of the safety circuit of a conventional combustion control device. FIG. 4 is an operation timing diagram of the safety circuit of the combustion control device of the present invention. 1... Microcomputer, 2... Relay drive section, 3... Relay section, 4... Relay power supply section, 5
... Relay power cutoff section, 6 ... Single pulse generation section, 7 ... Counter section, 8 ... Oscillator, 9 ... OR
Gate, 10... Combustion equipment monitoring department.

Claims (1)

[Scope of utility model registration request] a relay section 3 that drives various loads of combustion equipment;
Relay power supply unit 4 that supplies power to the relay unit 3
, a microcomputer 1 that controls the entire combustion equipment, a counter 7 and an oscillator 8 for detecting abnormal operation of the microcomputer 1,
A one-shot pulse generator 6 sends a reset signal to the microcomputer 1 only once in response to an overflow signal from the counter 7, and an emergency stop signal A (=overflow signal) from the counter 7 and an emergency stop signal B from the microcomputer 1. An OR gate 9 that takes a logical sum, and a relay power cutoff unit 5 that turns ON/OFF the power supply from the relay power supply unit 4 to the relay unit 3 based on the output signal of the OR gate 9.
and a combustion equipment monitoring unit 10 that monitors the operation of the combustion equipment, and when the microcomputer 1 is operating normally, the combustion equipment monitoring unit 10 monitors the operation of the combustion equipment, and in the event of any abnormality, the microcomputer 1 operates a relay power cutoff unit. 5 through the OR gate 9 to turn off each load on the combustion equipment and safely stop the combustion equipment. On the other hand, in the event that the microcomputer 1 becomes abnormal, the oscillator 8 and the counter 7 As a result, an emergency stop signal A is output to the relay power cut-off section 5 through the OR gate 9 to safely stop the combustion equipment, and a reset signal is issued once by the one-shot pulse generator 6 in order to return the microcomputer 1 to normal operation. The safety circuit for combustion control equipment is characterized in that the oscillation of an oscillator 8 is stopped and an overflow signal of a counter 7, that is, an emergency stop signal A is continued to be held until the microcomputer 1 returns to normal.