Survey Of Functions - Danfoss AK-PC 420 User Manual

Survey of functions

Function
Normal display
If the two displays are mounted:
The regulation temperature is displayed on EKA 164 (the one with buttons) (Pc or S7
or S8)
Pc will be shown on EKA 163. Both readouts will be in temperature
Reference
Unit
Here you can select whether the display is to indicate temperatures in °C or °F
0: Will give °C / bar
1: Will give °F / psig
Start/stop of refrigeration
Start/stop of refrigeration may also be performed with an external contact function
connected to the input named "ON input". (The input must be wired).
Set point
When "r33 ctrl.mode" is set at 1 or 3, it is regulated according to the set value + a pos-
sible displacement from a 0-10 V signal.
See also page 18.
Reference variation. See also page 18.
Regulation with setting 1 (or 2 if the reference is to vary with the outdoor tempera-
ture) will give the best regulation if the system is in balance. But if a lot of fans are
connected, it may be necessary to select setting 3 instead (or 4, if there is regulation
with the outdoor temperature). (Settings 3 and 4 will generally be preferable if a off-
set can be accepted between the reference and the actual regulation temperature)
1: No change of the reference. Regulation based on set setpoint + displacement with
a 0-10 V signal.
If there is a heat recovery signal, the reference will switch to the preset set point in
"r64".
2: Outdoor temperature forms part of the reference. The outdoor temperature is
measured with Sc3 sensor and the reference will always have a fixed value "r56 Min
tm K" over the measured outdoor temperature.
If there is a heat recovery signal, the reference will switch to the preset set point in
"r64".
Setting 1 and 2 operate with a PI regulation, but if the system is unstable and the PI
regulation not satisfactory the I element may be left out, so that the controller will be
with P regulation only.
3: As 1, but with P regulation (xp-band)
4: As 2, but with P regulation (xp-band)
5: As for 1, but with a minimum reference limit in accordance with outdoor tempera-
ture Sc3
6: As for 3, but with a minimum reference limit in accordance with outdoor tempera-
ture Sc3
Reference
The regulation reference is shown here.
Set point limitation
With these settings the setpoint can only be set between the two values.
(This also applies to regulations where the Xp band lies above the reference).
Max. permissible setpoint value. (Is set as an absolute value)
Min. permissible setpoint value. (Is set as an absolute value when "r33" = 1-4)
Correction of pressure measurement Pc
An offset adjustment of the registered pressure can be made.
Dimensioning temperature Min tm
The mean temperature difference across the condenser at low capacity (tm differ-
ence at max. load). This is the temperature difference between the air and condensing
temperature.
When "r33 Ctrl. Mode" is set at 2 or 4, regulation takes place according to a reference
that is "Min tm" over the measured outdoor temperature.
Reading of regulation temperature
This is where you can see the actual temperature being measured by the sensor cho-
sen for capacity regulation. The value is displayed in °C.
Set point value for heat recovery
When a heat recovery signal is received, regulation takes place according to the value
set here + any displacement via 0-10 V signal.
Average value for reference changes
A switch in the reference will be ramped up or down over this period of time. Set in
Kelvin/minute.
8 Manual RS8EL402 © Danfoss 03-2010
Para- Parameter by operation via
meter data communication
S7 °C
Pc °C
S8 °C
Condenser control
r05 Unit
(In AKM only °C is used, whatever the
setting)
r12 Main Switch
r28 Set Point °C
r33 Ctrl. mode
r29 Ref. °C
r30 RefMax °C
r31 RefMin °C
r32 AdjustPc
r56 Min tm K
r58 Ctrl temp
r64 Heat SP°C
r65 RefRamp
AK-PC 420