West Control Solutions N8800 - Manual (Page 21)

3.5.4 Self-tuning start
Start condition:
w For process evaluation, a stable condition is required. Therefore, the
controller waits until the process has reached a stable condition after
self-tuning start.
The rest condition is considered being reached, when the process value
oscillation is smaller than ± 0,5% of (rnG.H - rnG.L).
w For self-tuning start after start-up, a 10% difference from (SP.LO ... SP.Hi)
is required.
g
Self-tuning start can be blocked via 8800/8840 configurator ® (engineering tool)
( P.Loc).
Strt = 0 Only manual start by pressing keys Ù and È
simultaneously or via interface is possible.
Strt = 1 Manual start by press keys Ù and È simultaneously
via interface and automatic start after power-on and detection
of process oscillations.
3.5.5 Self-tuning cancellation
By the operator:
Self-tuning can always be cancelled by the operator. For this, press Ù and È
key simultaneously.With controller switch-over to manual mode after self-tuning
start, self-tuning is cancelled. When self-tuning is cancelled, the controller will
continue operating using the old parameter values.
By the controller:
If the Err LED starts blinking whilst self-tuning is running, successful self-tuning
is prevented due to the control conditions. In this case, self-tuning was cancelled
by the controller. The controller continues operating with the old parameters in
automatic mode. In manual mode it continues with the old controller output
value.
3.5.6 Acknowledgement procedures in case of unsuccessful self-tuning
Operation
8800 process controller 21 Self-tuning
Ada LED status Signification
blinks Waiting, until process
calms down
lit Self-tuning is running
off Self-tuning not activ
or ended
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°F