Danfoss AR05, Operation Instructions Manual, Page: 4 / 25

4 Reglermanual - VMGFF102
Figure 1 - Control board
3.2 - Electrical supply to boards
All boards are supplied from a common 24 V a.c. supply
referred to earth.
CAUTION: Maintain the correct polarity of the power supply
connection of the boards, to ensure that they are not
damaged.
In the event of a power supply interrupt, the unit restarts
automatically without the need for an external command.
However, any faults active when the supply is interrupted are
saved and may in certain cases prevent a circuit or unit from
restarting.
3.3 - Light emitting diodes on boards
All boards continuously check and indicate the proper
operation of their electronic circuits. A light emitting diode
(LED) lights on each board when it is operating properly.
•
The red LED that fl ashes for a two-second period - one
second on, one second off - indicates correct operation. A
diff erent rate indicates a board or a software failure.
• The green LED fl ashes continuously on all boards to
show that the board is communicating correctly over its
internal bus. If the LED is not fl ashing, this indicates a
LEN bus wiring problem.
• The orange LED of the master board fl ashes during any
communication via the CCN bus.
3.4 - The sensors
Pressure sensors
Two types of electronic (high and low-pressure) sensors are
used to measure the suction and discharge pressure in each
circuit.
Thermistors
The heat exchanger water sensors are installed in the enter-ing
and leaving side. The outdoor temperature sensor is
mounted under a metal plate. An optional water system
temperature sensor can be used for master/slave assembly
control (in the case of leaving water control).
In heat pump units a sensor placed on an air heat exchanger
pipe ensures defrost operation.
3.5 - The controls
Water circulation pump
The controller can regulate one or two water heat exchanger
pumps and takes care of automatic change-over between
pumps.
Heaters
They protect the heat exchanger (and the piping for units
without pump) against frost, if the unit has stopped and is
left energised.
Boiler
This output authorises start/stop of a boiler.
3.6 - Connections at the user terminal block
3.6.1 - General description
The contacts below are available at the user terminal block
on the NRCP2-BASE boards. Some contacts can only be used
if the unit operates in remote operating type (Remote).
\\MAINMENU\STATUS
Circuit B Total Capacity
CAPB_T 0 %
DEM_LIM 100 %
SP 4.2 °C
CTRL_PNT -28.9 °C
EMSTOP dsable
ENTER START/STOP
Contrast control
wheel
Back to the previous
screen
On/off key
- Unit stopped
- List of available operating
modes (only in local mode)
Green LED
Unit has stopped
Unit starts up
Unit in operation
Red LED
No alarm
Warning
Circuit or complete unit error
Up/Down key
- Navigation
- Modifi cation
Enter key
- Validation
- Selection access