Siemens Milltronics BW500 Operating Instructions Manual page 118

PID Control
9.4 PID Setup and Tuning
8. Again observe the oscillation of the control output. Compare results to the figures 4,5 and 6
below.
9. The
the
direction of change of the process variable. The
where the material control point is far away from the measuring point. An example of this
would be a weigh belt or conveyor with a belt scale (constant speed) being fed from a pre-
feeder some distance or more than a few seconds process time from the scale.
A properly set
6. A D term set too high induces high oscillations, as in figure 4. Omission of the
set too low, shows no effect on the system.
10.The above closed loop cycling procedure allows ease in start up, but final adjustments may
be necessary in actual process operation.
116
D
term is not critical in typical shearing type weigh feeder applications. The purpose of
D
term is to anticipate where the process is heading by looking at thetime, rate, and
D
term will make the initial oscillations around the setpoint smaller, as in figure
D
term becomes very useful in applications
Operating Instructions, 12/2016, A5E33482052-AD
D
term, or
BW500 and BW500/L