Manual Setting - Chauvin Arnoux STATOP 4849 Notice De Fonctionnement

3.10.3 Dwell function
The dwell function is enabled by configuring the alarm output to act as a dwell timer. The parameter
" ALm1 " needs to be set to the value 13. The alarm contact will now operate as a timer contact, with the
contact being open on initial start up. The timer begins to count down once the setpoint temperature is
reached. After the setting at " ASP1 " has elapsed, the alarm contact closes.
The dwell function may be used to operate an external device, such as an alarm siren (for example)
when a soak time has been reached.
In the example below, the ramp rate has
been set to 0, " ALm1 " = 13 and
" ASP1 " = 12 (minutes). Initial start up
is at zero time and the process climbs to
the 125°C setpoint. Once setpoint is
reached, the dwell timer begins to count.
After 12 minutes the alarm contact
closes. The STATOP 4849 will continue
to operate as a fixed setpoint controller.

3.11 Manual Setting

3.11.1 Manual P-I-D Adjustment
Whilst the Auto-tuning function selects control settings which should prove satisfactory for the majority
of processes, you may find it necessary to make adjustments to these arbitrary settings from time to
time. This may be the case if some changes are made to the process or if you wish to " fine-tune " the
control settings.
It is important that prior to making changes to the control settings, that you record the current settings for
future reference. Make slight changes to only one setting at a time and observe the results on the
process. Because each of the settings interact with each other, it is easy to become confused with the
results if you are not familiar with process control procedures.
Tuning Guide
Action
Proportional
Integral (reset)
Derivative (rate)
NOTE : These terms refer to the settings the controller uses to optimise control of the process. If you
aren't familiar with these terms - don't worry ! The Auto Tuning procedure of the controller will pre-set
them for you.
Symptom
Slow response
High overshoot or oscillations
Slow response
Instability or oscillations
Slow response or oscillations
High overshoot
Solution
Decrease Pb
Increase Pb
Decrease Ti
Increase Ti
Decrease Td
Increase Td
38
Control
Alarm
t (10')