Danfoss EKC 531D1 Manual De Instrucciones página 21

EKC 531D1 — Supplement to the manual
The PC reference
You may choose between four different regulation modes.
Basically 1 or 2 are recommended. But if the plant is unstable it
may become necessary to change over to 3 or 4.
1. PI regulation. Fixed reference i.e. constant condensing pressure.
2. PI regulation. Floating reference with outdoor temperature i.e.
variable condensing pressure.
3. As "1", but with P regulation. A somewhat higher condensing
pressure than indicated by the reference must be accepted here.
4. As "2", but with P regulation. A somewhat higher condensing
pressure than indicated by the reference must be accepted here.
1. PI regulation with fixed reference
Ref
The reference at any time, on the basis of which the controller
regulates, can be seen in "r29".
A reference (r28) is set here which with certainty can cope with all
kinds of loads.
2. PI regulation with floating reference
Ref
The reference follows the outdoor temperature Sc3. If the outdoor
temperature drops one degree the reference will also drop one
degree. The reference is adjusted according to the compressor
capacity with max. Xp value.
If you need to raise the condensing temperature for, say, heat
recovery, the setpoint (r28) must be set to this temperature.
EKC 531D1
This part will be added to the manual in
the coming update in October 2005.
Supplement to the manual - RS8DD502 © Danfoss 06-2005
To limit the variation in the reference, if floating reference is
choosen (mode 2 & 4), two limit values will have to be set. A max.
limit (r30) and a min. limit (r31). The total regulation reference (r29)
will not be able to go beyond these limits.
As a safeguard against too high condenser temperature a Pc max.
value (A30) also has to be set. If the temperature approaches this
value a cutout of the compressor will be started.
The different regulation modes are as follows:
Setpoint
If you need to raise the condensing temperature for, say, heat
recovery, an offset value (r34) has to be set.
The DI5 function must be defined to 1.
When a signal is subsequently received on the DI5 input the
reference will be raised.
The DI5 function must be defined to 1.
When a signal is subsequently received on the DI5 input the
reference will be changed to the r28 setting.
The reference at any time, on the basis of which the controller
regulates, can be seen in "r29".
Recommended setting for Xp is the ∆T of the condenser, typically
10 to 15 K.
If there is sensor failure on the outdoor temperature sensor the
reference will change over to the r28 setting.
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