Calibrating an LVDT
Model 493.02 Controller Service
Calibration
109
Task 3 Verify the conditioner polarity
This task checks the polarity of the conditioner. Different types of test
systems are configured with different conditioner polarities. The
polarity of the conditioner, the polarity of the valve driver, and the
orientation of system cabling all play a role in controlling the actuator
and determining how signals are displayed. This procedure assumes
the servovalve polarity is set to Normal on the Station Setup Drive
panel Valve tab.
1. Check the sensor connection.
Be sure the displacement sensor is properly connected.
2. Apply a positive actuator command.
Stand-Alone— Enable the front panel Dial, and then use the Dial
to increase the Setpoint adjustment for a positive command.
Automated — Open the Manual Command window, and then
click on the Enable Manual Command check box to enable
manual command. Increase the Manual Cmd adjustment for a
positive command.
3. Monitor the displacement feedback.
If the signal value is positive for actuator extension, the
conditioner polarity is correct. If desired, you can change the
conditioner polarity to make the signal value negative for actuator
extension.