Regin REGIO EEDO, Manual, Page: 45 / 108

Control functions
2.9 CO
2
control
CO
2
control is a function that enables the controller to regulate based on fresh air demand. CO
2
control is
performed by connecting a CO
2
sensor, and by letting the controller control the VAV output signal based on
the CO
2
setpoint and the current CO
2
level in the room.
CO
2
control can be used together with the controller modes that include a VAV sequence:
✓
H VAV
✓
C VAV
✓ VAV
✓ H C VAV
CO
2
control is managed via the VAV control function, by applying the VAV control configuration setting,
see section 2.6 .
The CO
2
sensor is connected to and configured on an analog controller input by using the value listed in
Table 2-26 . Regin's ED-RU-DOCS room unit has a built-in CO
2
sensor. When an ED-RU-DOCS room unit
is connected, the controller recognizes the built-in CO
2
sensor automatically, and no controller input
configuration is needed.
Table 2-26 CO
2
control configuration value and controller input type.
Configuration value Controller input type
CO2 sensor Analog
CO
2
control provides a specific setting, listed in Table 2-27 , that is only applicable for the controller modes
that include a cooling sequence. This setting is located in the Configuration -> Control functions -> Controller
mode pane in Application tool, and is shown when an applicable controller mode is selected.
Table 2-27 CO
2
control configuration setting.
Configuration setting Description
Cooling sequence controlled by Cooling demand: The cooling output signal is controlled based
on the cooling setpoint and the current room temperature (default
setting).
VAV control selection: The cooling output signal is controlled
according to the VAV control setting, see section 2.6 . That is,
either by:
✓ Cooling demand
✓ CO2 demand
✓ Cooling or CO2, the highest demand
Figure 2-40 illustrates the control behaviour for CO
2
control when a minimum limits is set for the VAV
output signal.
The demand for fresh air increases as the CO
2
level in the room rises. When the CO
2
level rises above the
CO
2
setpoint, VAV signal increases to respond to the fresh air demand. At 100% fresh air demand, VAV
signal reaches its maximum.
When the CO
2
level in the room is lower than the CO
2
setpoint and no fresh air demand exists, VAV signal
is at its minimum.
Regio Eedo manual, Rev. D 45