Belimo VRP-M - Page 17

VRP-M VAV
Adaptive VAV controller
www.belimo.eu Product information S4-VRP-M VAV • en • v2.0 • 11.2006 • Subject to changes 17 / 28
Bus operation
(Continued)
Note

mid
not available with DC 24 V supply.
Operating volumetric flow setting 
min
/ 
max
The setpoint selected over the MP-Bus is resolved by means of the 
min
and 
max
settings on
the VRP-M.
Function Volumetric flow Range

nom
Nominal OEM-specific value, depending on the application and the VAV unit type

max
Maximum 30 ... 100% of 
nom

min
Minimum 0 * ... 100% of 
nom
* The minimum volumetric flow setting 
min
varies according to the type of VAV unit and is also influenced
by the creep flow limitation function (see «Creep flow limitation / minimum setting limit»).
Open operating volumetric flow setting
The 
min
-/
max
setting can be left open if necessary, i.e. 
min
0% / 
max
100%. In this case, the
volumetric flow must be limited in the higher-level system.
This operating setting allows the limitation of the volumetric flow to be adjusted without altering
the parameters on the VAV controller.
Responsibility for the limiting function passes from the unit manufacturer to the system supplier
or integrator.
Priorities for bus signal (MP setpoint)
and control inputs 6 (z1) / 7 (z2)
Note
Note the speed of the MP-Bus!
If several signals appear simultaneously, they are processed according to the following table of
priorities.
Terminal Priority Function
6 z1 1 OPEN
7 z2 2 CLOSED / 
min
/ 
mid
/ 
max
3 MP override function
1 OPEN
2 CLOSED
3 
max
4 
min
5 
mid
6 –
7 
nom
4 MP setpoint 0 ... 100% = 
min
... 
max
Last setpoint
Bus fail function
The VRP-M saves the current setpoint, i.e. the last setpoint to have been received from a bus
master (VRP-M-Tool, UK24LON). If the MP network fails, the connected VRP-M detects this and
retains this setpoint until it receives a new one from the MP master.
Initial setpoint after power failure
The VRP-M starts with its MP initial status (setpoint 0%, corresponding to 
min
setting) if a power
failure occurs in the intervening period.
Reference signal
(e.g. UK24LON nviRelStpt)
[%]
[
max
]
CLOSED
OPEN

nom

max

mid
[
min
]

min
Volumetric flow actual value signal
(e.g. UK24LON nvcActualValue)
Volumetric flow [% 
nom
]
Reference signal
(e.g. UK24LON nviRelStpt)