Despatch Protocol Plus Controller (Heat/Cool) - Manual (Page 25)

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PID Page
The PID Page contains parameters which control the response to the setpoint and
process variable input. To access the PID Page, enter the Setup Mode. Press the Page
key until PID is displayed. Press the Menu key. Each parameter can be changed by
pressing the Menu key until the desired parameter is displayed, and then pressing the
keys to change the value.
Menu Item Display Description Range
Display units PID Temp Unit Set display units to °C or °F
°
C or
°
F
Proportional band PID PB(H) Set proportional band for tuning 1 to 56
°
C (1 to 100
°
F )
Integral reset PID I(H) Rep/min Set integral reset for tuning 0 to 100 Sec/repeat
Derivative Rate PID D(H) in sec Set derivative rate for tuning 0 to 500 Sec.
AutoTune PID AutoTune Enable auto tuning function DIS EN
Proportional band PID PB(C) Set proportional band for tuning 1 to 56
°
C (1 to 100
°
F )
Integral reset PID I(C) Rep/min Set integral reset for tuning 0 to 100 Sec/repeat
Derivative Rate PID D (C) in sec Set derivative rate for tuning 0 to 500 Sec.
Heat Offset PID Heat Offset Set PB up or down from Setpoint -6 to 6
°
C (-11 to 11
°
F )
Cool Offset PID Cool Offset Set PB up or down from Setpoint -6 to 6
°
C (-11 to 11
°
F )
The AutoTune parameter disables or enables the AutoTune function. To utilize
AutoTuning:
1. Access the Setup Mode.
2. Press the Page key until the display reads AutoTune. Press the
key to enable
the AutoTune.
3. Press the Page key for three seconds to exit Setup Mode.
4. Cycle power to the instrument.
5. Set Manual Mode to run. The display will alternately display AutoTune and
Manual.
If the Manual Mode setpoint is less than 50 degrees higher than the actual process
temperature, the AutoTune function will create an error condition. This can be cleared
by either cooling off the process temperature or increasing the setpoint until there is
more than 50 degrees between them. Once the AutoTune function is allowed to
complete tuning, the AutoTune parameter will disable by itself.
If you wish to cancel the AutoTune function, press the STOP key, access the PID page
in Setup Mode, and set the AutoTune parameter to Disable.