Types Of Regulation - Danfoss EKC 316A Reference Manual

Types of regulation

Single Loop (address o56 Reg.type = 1)
The EKC 316A has the traditional PI controlling function with the
Kp factor for Proportional Gain and Tn for Integration Time in se-
conds. This also is known as the Single loop control with only one
PI block as shown in the diagram below.
Superheat Ref.
+
-
Instability cause by too much Proportional Gain can be corrected
by reducing to value of the Kp factor. This should be done redu-
cing with small steps at a time and observing the results before
making further reductions.
If the superheat response is slow to changes, it can be increased
by reducing the value of the Integration Time Tn.
When tuning the superheat stability, it is good practise to have a
fixed superheat reference by making SH max the same as SH min.
8
SHref
PI Control
Superheat
(S2 – S1)
-
+
Refrigerant Temp.
Reference manual RS8ED102 © Danfoss 03-2006
Kp factor and Tn settings
ETS Valve Evaporator
Evaporator Temp. S1
S2
EKC 316A