JPS5930102A - Malfunction preventing circuit of electronic control device - Google Patents

Abstract

PURPOSE:To prevent a malfunction, by masking a common line of a contact of an output relay, until an operating signal is inputted from the first start signal, when service interruption is reset after it is detected. CONSTITUTION:A commercial electric power source 1 is applied to an operating circuit 5 through a constant-voltage radio wave 2. This circuit 5 is reset by an auto-resetting circuit 8 when the electric power source 1 is turned on or service interruption is reset. Also, the circuit 5 applies a control output signal corresponding to a signal of inputs 41-4m to relays 71-7n through an output interface 6, at the time of a normal operation. When a service interruption detecting circuit 3 detects service interruption, the circuit 5 executes processing of service interruption, and a common line cotrolling circuit 9 turns off a relay 10, and turns off a common line of output relay contacts 71a-7na by a contact 10a. This state is held until a start signal or an operating signal is inputted from the input signals 41-4m, after recovery of service interruption, the circuit 9 operates the relay 10 by these signals, and thereafter, the common line is turned on.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic control device, and more particularly to a malfunction prevention circuit for an electronic control device suitable for preventing malfunction in a transient state where a power source is turned off.

As shown in FIG. 1, a conventional electronic control device of this type receives input from an AC power supply 1 to a constant voltage power supply 2 and supplies DC voltage to each circuit. If a power outage occurs for some reason,
Before a complete power outage occurs, a signal is output from the power outage detection circuit 3 and the necessary processing is performed by the arithmetic circuit 5. Next, after the power is restored, when the power is turned on, the auto-reset circuit 8 is activated to issue an auto-reset pulse to initialize the arithmetic circuit. The circuit is now enabled and inputs 41 to 4 n
The arithmetic circuit 5 calculates according to the signal t, and operates the relays 71 to 7n via the output interface circuit 6.
Contact output circuit 71a outputs ~71Lσ. I was getting depressed. In this circuit, all contacts on the three lines are common, and when relays 71 to 7n operate, a direct signal is output, so if the DC voltage suddenly drops during a power outage, the control circuit will become uncontrollable, causing movements that do not match logic. and relay 7
When 1 to 7rL operated, erroneous signals were likely to be selected to the outside. Further, even when a power failure returns, an auto-reset pulse is generated from the rise of the DC power supply and the arithmetic circuit is in an uncontrolled state while the arithmetic circuit is initialized.

SUMMARY OF THE INVENTION An object of the present invention is to provide a malfunction prevention circuit for an electronic control device that solves the above-mentioned drawbacks.

The electronic control device of the present invention starts when a power outage is detected and after the power outage is restored, by masking both the contacts of the output relay from the first start signal until the operation signal is manually input. 'IIL 'J(+') This is to prevent unintended output malfunctions in transient states at the time of on/off.

Below, one embodiment of the present invention will be described with reference to FIG. Parts with the same numbers as in FIG. 1 indicate the same parts. When a shutdown occurs, it is usually the case that the performance n0 circuit is still fully operational.
When the power failure detection circuit 3 outputs a power failure signal "g", the power failure processing is performed in the circuit 5 and the common line control circuit 9 turns off the relay 10 until t. Therefore, no matter how the contact output circuits 71a to 77L (Z, relays 71 to 7rL operate), all signals remain in the OFF state.Next, when the power is restored, the arithmetic circuit 5 completes initialization with an auto-reset pulse. too,
The common line 1 control circuit 9 keeps the relay 10 off and masks the operations of the contact output cuffs 1a to full a to make them ineffective. The common line control circuit 9 is set and the relay 10 is activated only when the first start signal or operation signal is input from the input signals 41 to 41). The contact IQa is now turned on, and the signals at the points r+a, -'IILCL become valid. In this example, the human power (No. 1'i' hc contact signal) is used, but it is not limited to this.According to the present invention, the output side is completely masked in the transient state when the power is turned off or turned on. Therefore, it is possible to prevent unintended malfunctions due to the uncontrollable head Jψ1 in a transient state.This has the effect of increasing reliability and safety.

[Brief explanation of the drawing]

FIG. 1 is a control tltt diagram of a conventional example, and FIG. 2 is a control diagram of the present invention. 1. Exchange 10. Source 2: Constant voltage IL source circuit
3...R'ffl>; Detection circuit 41~4 m・
...Contact manual power 5...Arithmetic circuit 6...Output interface circuit 71~7n...') V-71α~
77Lσ...J point 1 corresponding to relays 71 to 7 n
14 power 8...Auto reset 0...Common line flill ml') and -
10cI... Contact of relay 10, r+-

Claims (1)

[Claims] In an electronic control device whose output circuit is composed of relay contacts, a common line control circuit is connected to the output side of a power failure detection circuit connected to a constant voltage power supply, and a common line control circuit is connected to the output side of the common line control circuit. After connecting the relay, processing the power failure signal from the power failure detection circuit in the arithmetic circuit, and turning off the common line control relay via the common line control circuit, the common line control circuit is set using only the input signal. A malfunction prevention circuit for an electronic control device, characterized in that the common line control relay is operated.