Tester for proportional directional-control and throttle valves
The WPG1 tester is used for actuation of proportional directional-control valves and also of non-position-controlled proportional throttle valves. The device adjusts the setpoint selected proportionally to the magnet current using Potentiometer P1. The rated current is selected using Selector Switch S4, as follows: 0.1A (Position 1), 0.4A (Position 2) or 1.2A (Position 3).
Switch S3 is used to optionally display measured data for Setpoint or Current in the coil of the valve on the display. Switch S2 is used for Fast (+/–10V) or Slow (+/–5V) movement. Switch S1 (Enable) is used to enable the end stages; instantaneous state is indicated by means of LED L1 (green). Switch S5 switches the output for a black-white valve.
The end stages of the WPG1 are equipped with a two-channel PWM (Pulse Width Modulation) current source. This permits precise current control of the output magnets, irrespective of any changes in the coil resistance. The two outputs are protected against ground fault and short- circuit in the coil. In addition, the end stages are also protected by means of self-resetting PTC fuses. If a short-circuit occurs, the supply voltage is switched off and the short-circuit is signa- lised as a fault by LED L2 (red).
The device can be returned to use once the short-circuit has been eliminated and the PTC fuses have cooled down.