West Control Solutions N8840 - Manual (Page 15)

g
Saved alarms (Err-LED is lit) can be acknowledged and deleted with the digital
input di1/2/3, the è-key or the Ò-key.
Configuration, see page 37: ConF / LOGI / Err.r
g
If an alarm is still valid that means the cause of the alarm is not removed so far
(Err-LED blinks), then other saved alarms can not be acknowledged and deleted.
Self-tuning heating ( ADA.H) and cooling ( ADA.C) error status:
3.5 Self-tuning
For determination of optimum process parameters, self-tuning is possible.
After starting by the operator, the controller makes an adaptation attempt,
whereby the process characteristics are used to calculate the parameters for fast
line-out to the set-point without overshoot.
The following parameters are optimized when self-tuning:
Parameter set 1:
Pb1 - Proportional band 1 (heating) in engineering units [e.g. °C]
ti1 - Integral time 1 (heating) in [s]
r only, unless set to OFF
td1 - Derivative time 1 (heating) in [s]
r only, unless set to OFF
t1 - Minimum cycle time 1 (heating) in [s]
r only, unless Adt0 was set to “no self-tuning” during
configuration by means of 8800/8840 Configurator.
Pb2 - Proportional band 2 (cooling) in engineering units [e.g. °C]
Operation
8840 profiler 15 Self-tuning
Error status Description Behaviour
0 No error
3 Faulty control action Re-configure controller (inverse
i
direct)
4 No response of process
variable
The control loop is perhaps not closed: check sensor,
connections and process
5 Low reversal point Increase ( ADA.H) max. output limiting Y.Hi or
decrease ( ADA.C) min. output limiting Y.Lo
6 Danger of exceeded
set-point (parameter
determined)
If necessary, increase (inverse) or reduce (direct) set-point
7 Output step change
too small (∆y > 5%)
Increase ( ADA.H) max. output limiting Y.Hi or reduce
( ADA.C) min. output limiting Y.Lo
8 Set-point reserve too
small
Acknowledgment of this error message leads to switch-over
to automatic mode.If self-tuning shall be continued,
increase set-point (invers), reduce set-point (direct)
or decrease set-point range
(r PArA / SEtp / SP.LO and SP.Hi )
9 Impulse tuning failed The control loop is perhaps not closed: check sensor,
connections and process