5.2.4 Control constant volume flow rate
q
vmin
or q
vmax
(switching)
S1
24 V AC/DC
Compact
- +
+
Y U B+ A-
-
Fig. 16: Switching between volume flow rates q
vmin
and
q
vmax
If the volume flow rate is to be switchable between two
fixed values (e. g., day/night changeover), a volt-free
switch contact provided by the customer can be used to
switch between the volume flow rate setpoint values
q
vmin
and q
vmax
(factory setting).
Switch S1 open
- q
vmin
Switch S1 closed - q
vmax
5.2.5 Control variable operation / override
controls
If the volume flow rate is to be switchable between sev-
eral fixed values (e. g., day/night changeover /
CLOSED / OPEN), it is possible to switch between four
or five different fixed operating states using potential-
free switching contacts provided by others. The
switches must be interlocked to avoid short circuits. For
the adjustment of the volume flow rate setpoint values,
functional overview’ on page 27
S1
T
VOC
CO
2
DDC
24 V AC/DC
Compact
- +
+
Y U B+ A-
-
y
S3
S4
S5
Fig. 17: Step operation 0 – 10 V DC
S2
S1
T
VOC
CO
2
DDC
24 V AC/DC
Compact
- +
+
Y U B+ A-
-
y
S3
S4
S5
Fig. 18: Step operation 2 – 10 V DC
T
Temperature sensor
VOC Room air quality sensor
CO
2
Carbon dioxide sensor
DDC Office automation
The functions shown in the table below refer to the
respective operated switch.
The switches must be locked against each other.
Never operate more than one switch.
Override controls OPEN / q
vmin
/ q
vmax
/ CLOSED
Switch
Control input signal
0 – 10 V
2 – 10 V
All open
Minimum volume flow rate q
vmin
S1 closed
Room temperature control
S2 closed
Not used
OPEN
S3 closed
Maximum volume flow rate q
vmax
S4 closed*
Damper blade CLOSED
S5 closed*
Damper blade OPEN
* Only with supply voltage 24 V AC; with the DC supply, the func-
tions S4 and S5 are not available.
Wiring
Connection diagrams > Control variable operation / override controls
Control component Compact XM0 • XS0 for VAV terminal unit TVE
20
