VI.KT.G6.02 © Danfoss | 2016.05 | 27
Maintenance
If you want to tune the PI regulation precisely, you can use the following
method:
• Set the ‘Tn’ (integration time constant line 6185) to its max. value (999 sec.).
• Decrease the value for the ‘Xp’ (proportional band line 6184) until the system starts
hunting with a constant amplitude (it might be necessary to force the system by setting
an extreme value).
• Find the critical time period on the temperature recording or use a stop watch.
Temp. Critical time period
Time
This time period will be characteristic for the system, and you can evaluate the settings from
this critical period.
‘Tn’ = 0.85 x critical time period
‘Xp’ = 2.2 x proportional band value in the critical time period.
If the regulation seems to be too slow, you can decrease the proportional band value by
10%.
