Untitled - HUBER

unistat control V3.8.1
Appendix A - Program Directory
(8) POKO Function „UNIPUMP with level monitoring"
This function is used to monitor if the “UNIPUMP” being controlled by the POKO is
operating in synchronisation with the Unistat pump. The operating status of the
“UNIPUMP” is signalled via a contact to the “Level” socket on the Unistat Control.
By non-synchronised operation a fault signal will be generated. This function is
particularly important when the status of the “UNIPUMP” is to be monitored.
Program 9: ‘control parameters’
! Beware: To adjust these functions, a basic knowledge of a PI-/PID- control theory is
required! The appropriate literature should be consulted. Generally, reasonable results
can be obtained using the set parameters for both internal and external control. There
are two control variations. The older (standard) variation uses a pair of variable P and I
and summarises into the so called ‘object mass’. The variant makes it possible to set a
proportional band (in K), before time (in s) and after set time (in s). Both variants have
in common that the parameter sets for internal and external controlling can be set
separately.
STANDARD – variations:
The so called ‘object mass’ is a variable, which is a numerical value from 0 to 15.
There are two different object mass settings, i.e. internal and external. These can be changed
using program 9. This value adjusts the controller parameters for thermoregulation. As
standard the value 5 is used. It might be necessary to set different parameters.
The following list indicates, what effects the ‘object mass’ has on the internal control sizes
‘P’ and ‘I’ (the amplification factors for the proportional and the integral part of the
controller). Please note that it is possible with the ‘object mass’ =15, to set the values for
‘P’ and ‘I’ independent of each other. Program 51 offers the possibility to make the parameter
search easier!
At set ‘object mass’ 15:
The values of ‘P’ range from 0 to 31. A 0 means, that the proportional part (proportional
value) of the controller is small, but not completely switched off. Increasing ‘P’ means that
the proportional part of the controller is having more influence. ‘P’ is an approximate
measurement for the ‘Proportional band’, used in conventional controller philosophies.
Note; The bigger the P value, the smaller the proportional band.
The value range for ‘I’ ranges from 0 to 127. A 0 means is this case, the integral part
(integral value) of the controller is completely inactive, so the ‘PI’ controller turned into a
simple ‘P’ controller. Increasing ‘I’ the integral part of the controller, the ‘I’ has more
influence. ‘I’ is inversely proportionally to the value used for the integral time in other
controller philosophies.
The following table is for the external thermoregulation:
Object mass: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
‘P’-Element 1 1 1 1 2 2 2 2 3 3 3 3 4 4 4
‘I’-Element 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3
Usually good results can be achieved with ‘object mass 15’ (P=4, I=8), for external
thermoregulation.
23