Configuration Manual
Version Document
A
001
A
ccess V4.X Configuration manual
21 (56) 2018-07-11
DX
DX with exchanger control
Operation settings: Data & Settings > Temperature control > Cooling (Cooling 2)
Water cooler
Control
When the unit is in running mode the heating valve is controlled by the analogue
output and digital output for pump control and/or signal for start heating.
Pump indication
A feedback from pump can be used, running indication or alarm indication.
DX cooler
Step controller Heating / DX cooling
As alternative or complement to the above mentioned analogue control, heating
and cooling can be activated in steps. The internal signal is then used to activate
digital outputs for control of the heaters/chillers. Up to four heater outputs and
three cooler outputs can be configured. There are two possible modes:
Sequential control
Each output step has individually settable on and off values in percent of the
control signal. The number of steps is equal to the number of heater/chiller groups.
Minimum on and off times can be set, i.e. the minimum time the step has to be
inactive or active for a change to occur.
Binary control
The heater power outputs should be binary weighted (1:2:4:8). The number of
loads to be controlled is set. Thereafter the program will automatically calculate
the individual Activate levels. Switching differential and minimum on/off times can
be set.
DX cooling with room or extract air control
If DX cooling is used in conjunction with room temperature control or extract air
temperature control, there are two Configure alternatives, DX cooling or DX
cooling with exchanger control.
DX cooling without exchanger control
When running cascade control, the supply air controller setpoint is normally
controlled by the room/extract air controller output signal.
When DX cooling is activated, the supply air controller setpoint is lowered to five
degrees (adjustable) below the setpoint given by the room/extract air controller.
This prevents the DX cooling from being activated/deactivated too often.