摘要 |
PROBLEM TO BE SOLVED: To enhance the safety by invalidating the emergency reset when a solenoid valve drive switch is not closed. SOLUTION: A current detection circuit 14 detects the state where all solenoid drive switches Q1-Q3 are closed under emergency reset through a current limit resistor 13. When all solenoid drive switches Q1-Q3 are not closed, an emergency reset limit circuit 20 is closed thus invalidating an emergency reset signal 19. |