Regio Midi manual
Chapter 7
Control modes
35
Control mode 7: Cooling/Cooling
Split output signal
In control mode Cooling/Cooling, the controller always functions as a cooling controller and
controls according to the basic cooling setpoint plus the setpoint adjustment. The control signal
is divided between the two outputs with a deadband in between. The first output (UO1) works
between 0...48 % of the control signal. When the control signal reaches 52 %, UO2 starts to
operate and will be 10 V when the control signal is 100 %. See the figure below:
Output signal
Cooling 2
Cooling 1
0 %
100 %
100 %
48 %
52 %
Cooling demand
Control mode 8: Heating/Cooling/VAV
This control mode offers the possibility to control three analogue outputs: heating, cooling and
VAV. When the controller is in cooling mode, the control signal is split between cooling and
VAV (this control mode is only available in …C3 models, except RC-C3DFOC), see figure
below:
To avoid Y2 and Y3 opening and closing frequently during switch-over, a saddle point is
implemented. Y2 will output 0…10 V (linear) when the controller output is 0…48 % and Y3
will output 0…10 V (linear) when the controller output is 52…100 %. In the saddle point, the
outputs will always be 100 % for Y2 and 0 % for Y3.
As an addition to the function described above, it is possible to connect a CO
2
sensor to RC-
C3DOC or use the built-in CO
2
sensor in RCC-C3DOCS. The output on Y3 will then be
affected by either cooling demand or by the CO
2
level rising too high. The output from the
CO
2
function is linear between two user-defined setpoints (see figure below).
A max limitation for both cooling and heating is available for Heating/Cooling/VAV-control.
The max limitation is configured 0...100 %, where 0 means the damper is entirely closed and
100 that the damper is entirely open. The function is activated by configuring the appropriate
parameter to a value less than 100. The cooling limitation is present in control modes 4, 5 and
8. The heating limitation is present in control modes 5 and 8.