| 摘要 |
PURPOSE:To protect a solenoid exciting circuit and to confirm a failed solenoid valve quickly and properly by detecting a voltage between output triac terminals of an SSR so as to protect the solenoid exciting circuit employing the SSR and sending an alarm signal to a PC at the occurrence of a fault. CONSTITUTION:If a solenoid valve driven by a solenoid 8 is faulty and an overcurrent takes place in the solenoid, a voltage between terminals 11 of a triac 10 rises and it is detected by a voltage detection section 16 through the terminal 11. When the detected value is more than a reference voltage for circuit protection set by a reference section 17, a transistor of an output driver 19 is turned on by a comparison section 18 and an alarm signal is sent to a PC input section 21. In receiving said alarm signal, the PC input section 21 activates an alarm processing program to turn off a PC output exciting a relay coil 22. Further, which solenoid valve hes a fault is discriminated by the input address of said alarm signal at the same time. |
