GE FVP110, Maintenance Manual

Page: 270 / 292

FVP 110 Fieldbus Valve Positioner Manual
254
GE Energy
If you cannot obtain expected response characteristics by Auto Tuning:
1. Change the modes of the AO function block and transducer block to O/S.
2. Verify the 10% step response and compare your response waveform with the three
types of response waveforms shown in “Control Parameter Tuning Procedure” on
page 254.
3. Adjust parameters by referring to the procedure of a waveform that has
characteristics similar to those of your waveform.
If Auto Tuning fails:
1. Adjust the zero-point and the span.
2. Set the parameters by referring to the default settings (factory settings) or tuning
examples in “Examples of Tuning Control Parameters” on page 258.
3. Verify the 10% step response and adjust the parameters according to the procedure
described in “Control Parameter Tuning Procedure” on page 254. For detail about the
control parameters, see “Description of Control Parameters” on page 259.
Control Parameter Tuning Procedure
Fast Response
Figure 86 Fast Response
Modifying overshoot
❑
Increase the value for SERVO_RATE to reduce an excessively rapid response.
Verify the 10% step response and increment the value by 0.2.
❑
If a significant improvement effect cannot be obtained by only incrementing the
value for SERVO_RATE in small steps of approximately 5% or less, input the value
in small steps in BOOST_ON_THRESHOLD [2] and decrement the value for
BOOST_VALUE [1] by 2 to decrease the boost.
❑
The same boost value is set on both the air delivery and exhaust sides using Auto
Tuning. If the overshoot on the exhaust side is larger than that on the air delivery
side for a double-acting model, input a negative value in X_BOOST_VALUE[1][2],