BLOCK-CONTACT 1111324 - Caterpillar

The response of the throttle actuator can be adjusted with the Caterpillar Electronic Technician (ET). Use Cat ET to change these three parameters:
Proportional gain
Integral gain
Derivative gainThese adjustments are provided in order to obtain optimum responses to changes in the load and in the speed. The adjustments also provide stability during steady state operation.Note: Adjustment of the proportional gain directly affects the speed of the throttle actuator when there is a difference between the actual engine speed and the desired engine speed. An excessive increase of the proportional gain may amplify instability.To change the gain, stability, or compensation, use the "Real Time Graphing" feature on the "Information" drop-down menu of Cat ET. The graph provides the best method for observing the effects of the adjustment.After you make adjustments, always test the stability by interrupting the engine speed and/or load. Use the "Bump" feature on Cat ET. Operate the engine through the entire range of speeds and of loads in order to ensure stability.To set the proportional gain, increase the proportional gain until the actuator becomes unstable. Slowly reduce the proportional gain in order to stabilize the actuator. Use Cat ET to bump the engine speed. Observe that the engine operates properly with little overshoot or undershoot.The adjustment of integral gain dampens the actuator's response to changes in load and in speed. Increasing the integral gain provides less damping. Decreasing the integral gain provides more damping. To reduce overshoot, decrease the integral gain. To reduce undershoot, increase the integral gain.Note: An increase of the integral gain may require a decrease of the proportional gain in order to maintain a stable operation.Note: Adjustment of the integral gain directly affects the damping of the throttle actuator. An excessive increase of the derivative gain may amplify instability.Decrease the derivative gain until a slow, periodic instability is observed. Then, slightly increase the derivative gain. Repeat the adjustments of the proportional gain and of the integral gain. Continue to increase the derivative gain and readjust the proportional gain and the integral gain until stability is achieved and the engine's response to changes in load and in speed is optimized.