West Control Solutions N4400 - Manual (Page 16)

6 USING THE PRE-TUNE FACILITY
The Pre-Tune facility is used to set the Setpoint Programmer’s PID control parameters to
values which are approximately correct in order to provide a base from which the Self-Tune
facility may subsequently optimise tuning. Pre-Tune may be activated as follows:
1. With the Set point Pro gram mer in Base Mode (with the RUN and HLD
in di ca tors OFF), press the Scroll key un til the Mes sage Dis play shows:
and the lower Main Dis play shows:
2. Press the MODE and Up keys to change the lower Main Dis play to:
in di cat ing that the Pre- Tune fa cil ity is now ac ti vated.
NOTES
1. If the process variable is within 5% of the input span from the
setpoint, the Pre-Tune facility cannot be activated and any attempt
to do so will have no effect.
2. Since the Pre-Tune facility is a single-shot operation, it will
automatically de-activate itself once the operation is complete.
To de-activate the Pre-Tune facility manually (with the Setpoint Programmer in Base
Mode), press the Scroll key to obtain the same Message Display as above; then press the
MODE and Up keys to change the lower Main Display from On to OFF.
Page 6-1 59215-6
59215