Micromod MOD: Modcell 2050R Users Guide - Manual (Page 160)

IB-23C650
TUNING
Tuning Procedure
The following procedure for tuning a controller is applicable to controllers set
up for P (gain), PI (gain plus integral), PD (gain plus derivative), and PID (gain
plus integral plus derivative) responses. If a recorder is available to record the
process variable, it will be helpful in determining optimum controller settings.
1. Start up controller in manual mode as described in the Setup section.
2. When process and set-point are together, switch to automatic mode.
3. For PI, PD, and PID controllers, turn off integral and derivative responses
as follows.
a. Access the TUNE MENU using the tag and UP keys.
b. In the TUNE MENU, scroll to [GAIN] and use the UP or DN key to set
a value of 1.0.
c. Scroll to [RESET ENABLE] and enter NO to turn off the integral
response.
d. Scroll to [PREACT] and set the value to “0” to turn off the derivative
response.
e. Return to the DISPLAYS MENU. This procedure has removed all but
the gain response from the system.
4. Create a disturbance in the system by adjusting the set-point a small
amount either up or down.
The resulting disturbance must be large enough to observe, but not so
large that it causes signal saturation at any point in the control loop. This
means that the controller output should be within its working range of 0 to
100% at all times during the recovery, and the process variable change
during recovery should be small enough to be considered linear about the
set-point.
5. Hold the set-point at this value until the process variable begins to move,
then return the set-point to its original value.
6. Compare the recorded oscillation with Figure 17. Cycle B should be
approximately 1/4 of cycle A as shown in the figure. If it is not, change
the gain setting and repeat Steps 4 and 5.
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