| 摘要 |
PROBLEM TO BE SOLVED: To provide a control unit of hydraulic construction machinery that can detect the short-circuiting or disconnection of wiring for connecting a solenoid proportional valve to a voltage converter and can stop the drive of the solenoid proportional valve speedily when the short-circuiting or disconnection of the wiring is detected. SOLUTION: The control unit of the hydraulic construction machinery comprises a controller 1, an IC2 for PWM conversion, a first amplifier 3, the multichannel solenoid proportional valve 4, the voltage converter 5, a multiplexer 6, a second amplifier 7, an integral section 8, and an A/D converter 9. The voltage adder 10 adds a prescribed voltage to the voltage converter 5, the amplifier 7, and the integral section 8. The controller 1 determines whether the output value of the A/D converter 9 is equal to 0, and determines whether output from the IC2 for PWM conversion is present or not, detects the short-circuiting or disconnection of wiring (b) for connecting the solenoid proportional valve 4 to the voltage conversion section 5, and controls the stop of PWM output from the IC2 for PWM conversion. COPYRIGHT: (C)2005,JPO&NCIPI
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