© Danfoss A/S (DCS-IMCGPD/sw), 2015-03
DKRCC.PS.R1.A3.02 / 520H9752
11
Manual
Electronic superheat controller, type EKC 312
Appendix 4
Regulation algorithms for the superheat. (loop ctrl.).
There are two algorithms to choose between.
They are set in ”o56”.
Loop Ctrl.=1
This regulation algorithm is used for the classical method
and is recommended for known applications – e.g. for earlier
installations with a Danfoss controller. For a start the values
for Kp, and Tn can be set to values corresponding to the earlier
ones.
Loop Ctrl. =2
This setting is recommended if only one regulation of the
superheat is required.
The regulation algorithm necessitates the mounting of a
temperature sensor in the media.
The S4 and T0 temperatures also form part of an inner loop
regulation.
Start of controller
When the electric wires have been connected to the controller,
the following points have to be attended to before the regulation
starts:
1. Switch off the external ON/OFF switch that starts and stops the
regulation
2. Follow the menu survey on page 6, and set the various
para-meters to the required values
3. Switch on the external switch, and regulation will start
4. Follow the actual superheat on the display
If the superheating fluctuates
When the refrigerating system has been made to work steadily,
the controller’s factory-set control parameters should in most
cases provide a stable and relatively fast regulating system.
If the system however fluctuates this may be due to the fact that
too low superheat parameters have been selected:
Adjust: n09 and n10.
Alternatively it may be due to the fact that the set regulation
parameters are not optimal.
If the time of oscillation is longer than the integration time:
(T
p
> T
n
, (T
n
is, say, 240 seconds))
1. Increase T
n
to 1.2 times T
p
2. Wait until the system is in balance again
3. If there is still oscillation, reduce K
p
by, say, 20%
4. Wait until the system is in balance
5. If it continues to oscillate, repeat 3 and 4
If the time of oscillation is shorter than the integration time:
(T
p
< T
n
, (T
n
is, say, 240 seconds)).
1. Reduce K
p
by, say, 20% of the scale reading.
2. Wait until the system is in balance.
3. If it continues to oscillate, repeat 1 and 2.