FUNCTION CODE 150 CALIBRATION
TUNING THE CONTROLLER GAIN
B - 4
I-E96-322A
®
TUNING THE CONTROLLER GAIN
The practical method of setting controller gain requires an indi-
vidual with turbine control experience. The individual tuning
the system should be familiar with plant operation under nor-
mal conditions, know turbine start-up procedures and have
experience in tuning control systems. In cases where the valve
is a distance from the control cabinet or separated by barriers,
two people are needed to tune the system. One person observes
the valve operation while the other person sets the controller
gain and enters position demand. Communication by tele-
phone or intercom is recommended. The radio frequency inter-
ference from walkie-talkies can cause problems with the
control system. Exercise extreme care if using a walkie-talkie.
When keying the unit, the operator should be at least two
meters away from the cabinet and the cabinet doors closed.
Before tuning the controller gain, verify that the following con-
ditions exist:
1. Calibration of the HSS module, hydraulic actuator and
LVDT transformer is complete.
2. The controller gain is set to 1 (dipswitch S3 pole 8 is
closed). Refer to Table
for controller gain switch settings.
3. The calibration command bit in the block address specified
in S3 is set to 0 (normal operation).
4. The GO/HOLD bit in the block address specified in S4 is
set to 0 (HOLD).
5. The turbine is off-line.
To tune the controller gain:
1. Enter position demands (via the operator interface) of 25%,
50%, 75% and 90%, opening the valve. Observe the response of
the throttle valve at each demand level. The valve should
respond without oscillating at any level of demand.
2. Enter position demands (via the operator interface) of 25%,
50%, 75% and 90%, closing the valve. Observe the response of
the throttle valve at each demand level. The valve should
respond without oscillating at each level of demand.
3. Check valve operation. If the valve operates smoothly at all
demand levels, continue. If the valve oscillates go to Step 7.
4. Remove the HSS module and raise the controller gain
(switch 2) to the next setting. For example, if the gain is 1 (pole
8 is closed), change the gain to 2 (close pole 7, open pole 8).
