MTS Series 793 - Manual (Page 56)

MTS Series 793 Tuning and Calibration
How to Set Servovalve Polarity
Tuning Procedures 56
How to Set Servovalve Polarity
Servovalve polarity refers to the direction the servovalve moves the actuator in
response to a positive command. It can be set to normal or invert.
Typically, a servovalve with a normal polarity extends the actuator in response to
a positive command. Conversely, a servovalve with an inverted polarity retracts
the actuator in response to a positive actuator command.
Before you can set servovalve polarity, you must determine if the current
servovalve polarity follows the normal convention.
The procedures that follow determines servovalve polarity by having you
observe actuator movement while applying a positive Setpoint command to the
actuator. Procedures for both Standalone and Automated Controllers are
described.
Please note the following:
• The polarity of the servovalve must be checked before sensor calibration
begins and before hydraulic pressure is applied for the first time.
• The polarity of any servovalve is generally set when the valve is installed.
Important The combination of the conditioner polarity and the servovalve
polarity affects the final output signal. The conditioner polarities
should be set before the servovalve polarity because they do not
need hydraulics to be turned on. In general, you will set the
conditioner and servovalve polarity the same.
1. Get things ready.
Standalone FlexTest SE Controllers:
A. Ensure the actuator can be fully extended without contacting anything.
You may need to remove any obstructions.
B. Press the Status button twice to display the Status menu, and for
Control Mode, select displacement.
C. For Access Level, select Tuning.
Automated Controllers:
A. Ensure that the actuator can be fully extended without contacting
anything. You may need to remove any obstructions.