TECO speecon 7200ma Instruction Manual page 112

The above parameters are factory set for optimum results for most applications, and
generally do not need to be changed.
The PID Primary Delay Time is a parameter that adds a filter to the PID output to keep
it from changing too quickly. The higher the setting, the slower the PID output will change.
All of these parameters are interactive, and will need to be adjusted until the control
loop is properly tuned, i.e. stable with minimal steady-state error. A general procedure
for tuning these parameters is as follows:
1. Adjust Proportional Gain until continuous oscillations in the Controlled Variable
are at a minimum.
2. The addition of Integral Time will cause the steady-state error to approach zero.
The time should be adjusted so that this minimal error is attained as fast as possible,
without making the system oscillate.
3. If necessary, adjust derivative time to reduce overshoot during startup. The drive's
acceleration and deceleration rate times can also be used for this purpose.
Output
Output
Output
Output
Before
After
Time
After
Before
Time
Before
After
Time
Before
After
Time
If overshoot occurs, shorten the derivative
time (D) and lengthen the integral time (I).
To rapidly stabilize the control conditions
even when overshooting occurs, shorten the
integral time (I) and lengthen the derivative
time (D).
If oscillation occurs with a longer cycle
than the integral time (I) setting, it means
that the integral operation is strong. The
oscillation will be reduced as the integral
time (I) is lengthened.
If oscillation cycle is short and approx. the
same as the derivative time (D) setting, it
means that the derivative operation is
strong. The oscillation will be reduced as
the derivative time (D) is shortened. If even
setting the derivative time (D) to 0.00
cannot reduce oscillation, then either
decrease the proportional gain (P) or raise
the PID primary delay time constant.
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