Belimo VRD2 - TROX
Belimo VRD2 - TROX
Belimo VRD2 - TROX
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
<strong>Belimo</strong> <strong>VRD2</strong><br />
Characteristic of Actual Value Signal Description of Function<br />
V · nom<br />
(100 %)<br />
Volume flow<br />
V · min pub.<br />
A 2 to 10 VDC (standard)<br />
V · actual = V · nom<br />
U 5 - 2<br />
8<br />
B 0 to 10 VDC<br />
V · actual = V · nom<br />
Adjustment<br />
range<br />
0<br />
0 2 Actual value signal U5 10 VDC<br />
U 5<br />
10<br />
Characteristic of Volume Flow Control Variable<br />
Volume flow<br />
V · max<br />
V · min<br />
A 2 to 10 VDC (standard)<br />
V · set = U3 - 2<br />
(V<br />
8<br />
· max -V · min) + V · min<br />
V · nom<br />
(100 %)<br />
V · min pub.<br />
0<br />
0 2 Control signal U3 10 VDC<br />
B 0 to 10 VDC<br />
V · set = U 3<br />
10<br />
(V · max -V · min) + V · min<br />
3<br />
The volume flow is measured on the dynamic differential<br />
pressure principle. The effective pressure ∆p w of the<br />
differential pressure sensor in the terminal unit allows the<br />
detection of a partial volume flow passing trough the<br />
transducer. This partial volume flow which is proportional<br />
to the total volume flow is measured, temperature compensated<br />
and linearised with two temperature-dependent<br />
resistors.<br />
The measurement range is set to suit the unit size during<br />
factory calibration, so that 10 VDC always corresponds<br />
to the unit nominal volume flow rate (V · nom).<br />
The signal is processed by a microprocessor. The actual<br />
volume flow is available as a linear voltage signal U 5.<br />
The required volume flow is set by the room temperature<br />
controller via the control signal within the limits of V · min<br />
and V · max.<br />
It is possible to select either 2 to 10 VDC (standard) or<br />
0 to 10 VDC as the voltage range for signal transmission.<br />
This facilitates an adjustment to the working ranges<br />
of different room temperature controllers or DDC outstations.<br />
The set volume flow can be overridden using<br />
switched controls.<br />
The <strong>VRD2</strong> determines the required volume flow in<br />
accordance with the characteristic shown and compares<br />
this with the actual value. The damper actuator is controlled<br />
according to the deviation.<br />
The <strong>Belimo</strong> volume flow controller <strong>VRD2</strong> can only operate<br />
with the matched <strong>Belimo</strong> actuators which are optimised<br />
for volume flow control. It is not possible to connect<br />
other 3-point or 0 to 10 VDC actuators.
Change language