CONTREX MLP-Trim - Manual (Page 181)

C - 13
CP-64 DISPLAY MODE FOLLOWER
In the Follower mode of operation, Display Mode Follower (CP-64) determines how the data will
display in Tach (CP-40).
Enter "2" to display the ratio of feedback to lead, in E.U. (Follower)
Enter "1" to display the feedback in E.U.s/Time (Master)
CP-65 GAIN (PROPORTIONAL)
To achieve an acceptable level of speed error, adjust Gain (CP-65) until the system stabilizes.
With Integral (CP-66) and Derivative (CP-67) set to “0” , reduce the Gain (CP-65) value until the
system becomes unstable, then increase it slightly until the system stabilizes. Reduced values
will increase Gain. To verify the stability of the speed changes, you can access Tach through
either the Tach key or the Tach (MP-40).
CP-66 INTEGRAL
In systems that require greater accuracy, it may be necessary to adjust the value of Integral (CP-
66) to reduce any remaining speed error. In systems with low inertia, the speed error will be
reduced more quickly if you enter low values in Integral (CP-66). An entry that is too low,
however, can create instability or overshoot the setpoint before reaching the correct value.
Generally, use larger entries for Integral (CP-66) on systems with a large inertia. While switching
between the high and low setpoints, decrease the Integral's default value of “2000” until the
speed error is reduced within an acceptable time frame. To verify the stability of the speed
changes, you can access Tach through either the tach key or the Tach (MP-40).
CP-67 DERIVATIVE
In systems with a very large inertia, use Derivative (CP-67) to reduce the overshoot from the
integral term. Decrease the value of Derivative (CP-67) until the overshoot is acceptable. The
system may operate erratically or become unstable if the value of Derivative (CP-67) is too
small.
CP-69 TRIM AUTHORITY
Trim Authority determines how much influence the PID term has on the control output. If stability
cannot be obtained through the standard tuning procedure, reduce CP-69 until stable tuning is
achieved.