Manual Control - Brainchild C21 User Manual

ADJUSTMENT SEQUENCE ADJUSTMENT SEQUENCE
(1) Proportional Band ( PB ) (1) Proportional Band ( PB )
(2) Integral Time ( TI ) (2) Integral Time ( TI )
(3) Derivative Time ( TD ) (3) Derivative Time ( TD )
Figure 3.9 shows the effects of PID adjustment on process response. Figure 3.9 shows the effects of PID adjustment on process response.

3 -13 Manual Control

3 -13 Manual Control
Operation:
To enable manual control the LOCK parameter should be set with To enable manual control the LOCK parameter should be set with
NONE, then press NONE, then press
or or (Cooling output) will appear on the display. Press (Cooling output) will appear on the display. Press
seconds then the MAN indicator (for C91) or the display (for C21) will seconds then the MAN indicator (for C91) or the display (for C21) will
begin to flash. The controller now enters the manual control mode. begin to flash. The controller now enters the manual control mode.
indicates output control variable for output 1, and indicates output control variable for output 1, and
indicates control variable for output 2. Now you can use up- indicates control variable for output 2. Now you can use up-
down key to adjust the percentage values for the heating or cooling down key to adjust the percentage values for the heating or cooling
output. output.
The controller performs open loop control as long as it stays in manual The controller performs open loop control as long as it stays in manual
control mode. control mode.
Exit Manual Control Exit Manual Control
To press To press key the controller will revert to its normal display mode. key the controller will revert to its normal display mode.
SYMPTOM
Slow Response Slow Response
High overshoot or High overshoot or
Oscillations Oscillations
Slow Response Slow Response
Instability or Instability or
Oscillations Oscillations
Slow Response or Slow Response or
Oscillations Oscillations
High Overshoot High Overshoot
Table 3.2 PID Adjustment Guide Table 3.2 PID Adjustment Guide
for several times then for several times then
UM0C911C
SOLUTION
Decrease PB Decrease PB
Increase PB Increase PB
Decrease TI Decrease TI
Increase TI Increase TI
Decrease TD Decrease TD
Increase TD Increase TD
(Heating output) (Heating output)
for 5 for 5
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