Modifying Overshoot; Improving The Stabilization Time And Slow Overshoot; Improving The Response Time; Checking Hunting Operation - GE FVP110 Maintenance Manual

Moderate Response with a Flat
❑
If necessary, decrease the value for SERVO_GAIN to 2/3 or 1/2 of the originally
entered value.
❑
If necessary, set the SERVO_DEADBAND. Set a value in approximately the
range of a limit cycle (recommended upper limit is 2%).
❑
If the limit cycle is not eliminated, check the piping and feedback lever installation
by referring to Section 18.4.

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 necessary, increment the value for SERVO_RESET by 5.
❑
The same boost value is set on both the air delivery and exhaust sides by 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], without changing the value of 0 in X_BST_ON_THRESHOLD [1] [2] and
X_BST_OFF_THRESHOLD [1] [2]. First, try to input a negative value of half that
of BOOST_VALUE [1] [2], and if necessary, increment or decrement the value by
1.

Improving the Stabilization Time and Slow Overshoot

Decrease the value for SERVO_RESET to improve the capability of tracking the target
value. However, if the value is too small, the hunting operation or limit cycle may occur.
Verify the 10% step response and decrement the value by 2 to 3.

Improving the Response Time

❑
Increment or decrement the value for BOOST_VALUE [1] [2] and
X_BOOST_VALUE [1] [2] by 2, respectively.
❑
If necessary, increment the value for SERVO_GAIN by 30.

Checking Hunting Operation

Input a value in a large step of approx. 80% to ensure the hunting operation does not
occur. If the hunting operation does occur,:
1. Decrease the value for SERVO_GAIN to 2/3 or 1/2 of the originally entered value.
2. Increase the value for SERVO_RESET by approx. 1.5 times.
After tuning the control parameters, re-check each parameter if necessary.
257
Manual Tuning Guideline