Woodward ProAct I, Product Manual

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ProAct I/II Manual 04121
42 Woodward
Stability, Actuator Compensation, Gain Ratio, Window Width
11. Stability (also known as Reset) compensates for the lag time of the engine.
It adjusts the time required for the control to return the speed to zero error
after a disturbance. Stability is adjusted to prevent slow hunting and to
minimize speed overshoot after a load disturbance.
12. Compensation compensates for the actuator and fuel system time constant.
13. Gain Ratio operates in conjunction with the Window Width and Gain
adjustments by multiplying the Gain set point by the Gain Ratio when the
speed error is greater than the Window Width. This makes the control
dynamics fast enough to minimize engine speed overshoot on start-up and
to reduce the magnitude of speed error when loads are changing. This
allows a lower gain at steady state for better stability and reduced steady-
state actuator movement.
14. Window Width is the magnitude (in ± rpm) of a speed error at which the
control automatically switches to fast response. The control does not use
the absolute value of speed error, but an “anticipated” speed error, to make
this switch. This method provides for quick switching to the high gain value
when an off speed occurs, and early switching to the low gain value when
recovering from the speed transient. This provides smoother switching than
if the absolute speed error were used for the window.
Menu 2—Alternate Dynamics Settings
Menu 2 should be programmed similar to Menu 1, but with the alternate fuel or
other operating condition expected. The four Gain settings and breakpoints may
be set like those used in Menu 1. The Stability, Compensation, Gain Ratio, and
Gain Window will probably be quite different if different fuels are being used.
If the engine will not use the alternate operating condition, the menu will not have
to be programmed or it can be programmed identically with the Menu 1 to
prevent unintentional changes in the dynamics program.