Basic Documentation

14 / 42
Siemens VAV Compact Controller Modbus RTU A6V10631862_en--_e
Smart Infrastructure 2021-10-26
3 Functionality / application
3.1 Fields of application
VAV Compact Controllers are primarily used for controlling a variable or constant
air volume flow.
System environments:
• Building automation systems using Modbus RTU (third-party integration and
freely programmable devices)
Application fields:
• Supply air control
• Extract air control
• Supply/extract cascade control with
– Ratio control 1:1
– Ratio control (positive/negative pressure)
– Differential control (positive/negative pressure)
• Air dampers with a nominal torque of up to 5 or 10 Nm
VAV Compact Controllers are not suitable for environments where the air is
saturated with sticky or fatty particles or contain aggressive substances.
3.2 Application examples
VAV Compact Controllers can be used in supply air and in supply / extract air
control applications. Demand-controlled ventilation (DCV) is possible when a
communication link to the supply / extract air fans of the air-handling unit (AHU) is
established, and the AHU controller offers the required control algorithm.
3.2.1 Supply and extract air control
If one VAV Compact Controller is used for supply air and one for extract air, these
are usually controlled individually by the supervisory controller. By setting their
volume flow limits (V
min
and V
max
) according to the setting instructions in section 0,
constant, positive, or negative pressure in a zone or a room can be achieved.
When omitting the extract air part, a simple supply air control application can be
realized. Disadvantages are that ventilation conditions in the room or zone can’t be
controlled precisely.
Bus
T
MV
.
MV
.
N2
N1
N2
Bus
Bus
Bus
Application
Note
Supply / extract air
control
Legend:
Bus Fieldbus (Modbus, BACnet,
KNX etc.)
N1 Room unit with temp. sensor
N2 VAV Compact Controllers
(supply air / extract air)