Hydraulic drive system has monitoring unit that receives control signal and pressure signal from control unit and pressure sensor to produce error signal based on comparison signals for displaying error of switching valve

摘要

The hydraulic drive system (10) has pump (12) that conveys hydraulic fluid to actuator (14). A switching valve (13) sequentially stops and releases appropriate fluid. A control unit (20) controls switching valve by control signal (21). A pressure sensor (22) provided at downstream and/or upstream of the switching valve measures pressure of hydraulic fluid and produces a pressure signal (23). A monitoring unit (24) receives control signal and pressure signal to produce an error signal based on comparison of control signal and pressure signal for displaying error of switching valve.