Woodward GCP-30 Series - Page 35

Manual 37365A GCP-30 Series Packages - Genset Control
© Woodward Page 35/179
CAUTION
The following must be ensured when tuning a controller:
• Ensure that the emergency shutdown system is operational
• While determining the critical frequency, pay attention to the amplitude and frequency
• If the two values change uncontrollably, initiate
 EMERGENCY SHUTDOWN 
Initial state: The start position of the speed or voltage controller is determined using the initial state of the con-
troller. If the controller output is disabled, the basic setting can be used to output a fixed controller position. If
the MANUAL operation mode has been selected, the initial state signal is output only after the engine "START"
button has been pressed. Even when the analog controller output is disabled, the initial state can be freely ad-
justed (e.g. the speed controller can be controlled in a linear manner). When the "STOP" button is been pressed,
the analog controller is turned off.
Controller outp.
Init.state= 000%
Initial state of the actuator 0 to 100 %
The value entered for the initial state is the start reference point for a speed or vol-
tage controller. If the output to that particular controller has been disabled, the out-
put will act as a control position reference point.
General settings: The setting rule described below only serves as an example. It cannot be assumed that this is
the proper method of control for your system since every system behaves uniquely.
There are various methods of setting a controller. The setting rules of Ziegler and Nichols are explained below
(determination for abrupt disturbances on the system input); this setting method assumes a pure lag element con-
nected in series with a first-order lag system.
1. The controller is operated as a P-loop only controller (where T
n
= ∞ [screen setting: T
n
=0], T
V
= 0).
2. Increase gain K
PR
(P-gain) until K
P
= K
Pcrit
and the control loop starts to oscillates continuously.
ATTENTION
If the engine starts to oscillate uncontrollably, carry out an emergency shutdown and alter the screen set-
ting accordingly.
3. At the same time, measure the critical cycle duration T
crit
4. Set the parameters: