BC0

VAV terminal units control the volume flow in a closed loop, i.e. measurement – comparison – correction. The volume flow rate is measured via the effective pressure. This is done via an effective pressure sensor. An integrated differential pressure transducer converts the effective pressure into a voltage signal. The volume flow rate actual value is available as a voltage signal. The factory setting is such that 10 V DC always corresponds to the nominal flow rate (q_vNom). The volume flow rate setpoint value comes from a higher-level controller (e.g. room temperature controller, air quality controller, central BMS). Variable volume flow control results in a value between q_vmin and q_max. It is possible to override the room temperature control, e.g. by a complete shut-off of the duct. The controller compares the differential pressure setpoint value to the actual value and controls the actuator accordingly if there is a difference.

Compact controllers for VAV terminal units

Note: ¹ LMV-D3-MP TR with clamping device can be used as a replacement part for LMV-D3-MP-F TR with positive lock connection

Compact controllers BC0, LMV-D3L-MP-F TR

Compact controllers BC0, LMV-D3-MP TR and LMV-D3-MP-F TR

Compact controllers BC0, NMV-D3-MP TR and NMV-D3-MP-F TR

Compactregler BC0, SMV-D3-MP TR

Commissioning

• On-site adjusting is not required
• As the volume flow rates are factory-set, the terminal units have to be installed at the specified locations
• After successful installation and wiring, the controller is ready for use by using the analogue interface
• Comply with the volume flow rate control ranges of the VAV terminal units, do not set a volume flow rate which is below the minimum flow rate
• For operation with MP-Bus interface: additional commissioning steps such as assigning a participant address are necessary

LED display and operation
Adjustment LED (green):

• Off: No supply voltage
• On: Operation
• Press key: Triggering of the rotation angle adjustment

Address LED (yellow):

• Off: Normal operation
• Flickering: MP communication active
• On: Adjustment or synchronisation in progress
• Flickering: Request for addressing from the MP master
• Press key: Confirmation of addressing 

Service tool range of functions

R,W = Read and write access.

R = Read only

W = Write only

- = Function is not available with this service tool.

Product details

Analogue interface 0 – 10 V DC or 2 – 10 V DC
The analogue interface can be set for signal voltage range 0 – 10 V DC or 2 – 10 V DC using the service tools. The assignment of the setpoint value or actual value of the volume flow rate to the voltage signal is shown in the characteristic line displays. 

Setpoint value default setting
Variable operation:

• In the variable operating mode, the setpoint value setting is set at cable wire Y with an analogue signal
• The selected signal voltage range 0 – 10 V or 2 – 10 V DC is assigned to the set volume flow rate range q_vmin – q_vmax
• Volume flow rate range q_vmin – q_vmax is set in the factory according to the order code
• Subsequent adjustment of q_vmin or q_vmax is possible using service tools, TROX FlowCheck App, adjustment device ZTH-EU or PC-Tool

Constant value mode:

• In the constant value mode operating mode, an analogue signal is not required at cable wire Y
• The set flow rate constant value q_vmin is used
• Volume flow rate q_vmin is set in the factory according to the order code
• Subsequent adjustment of q_vmin is possible using service tools, TROX FlowCheck App, adjustment device ZTH-EU or PC-Tool

Actual value as feedback for monitoring or tracking control

• The actual volume flow rate measured by the controller can be tapped as a voltage signal at cable wire U in the default setting
• The selected signal voltage range 0 – 10 V DC or 2 – 10 V DC is mapped to the volume flow rate range 0 – q_vNom
• The actual value output U can be reconfigured by others to output the damper position
• Selected signal voltage range 0 - 10 V DC or 2 - 10 V DC is then mapped to the damper blade position 0% (CLOSED) - 100% (OPEN).

Override control

For special operating situations, the volume flow controller can be put in a special operating mode (override control). The following modes are possible: control q_vmin, control q_vmax, damper blade in the OPEN position, damper blade CLOSED. Override control can be activated by:

• A suitable connection at signal input Y as per the connection diagrams through connection with external switching contacts/relays. OPEN and CLOSED are only available if the controller is supplied with alternating current (AC).
• Service tools such as ZTH-EU, PC-Tool or TROX Flow-Check app are activated
• A bus timeout monitoring is activated. (only in MP-Bus operation)
• A control signal at signal input Y is activated (only override control CLOSED). See the following table (only in operation with analogue setpoint value)

Override control CLOSED via control signal on control signal Y

The override control CLOSE can also be activated by observing certain conditions with the command signal. The following table summarises the boundary conditions.

Notes:

¹ Activation of control operation with 0 –10 V and q_vmin set to = 0:

The applicable volume flow rate range depends on the basic unit (TVJ/TVT: 20 – 100% of q_vnom; all other basic units: 10 – 100 % of q_vnom). This means that setpoint defaults can be achieved only from 2 V DC (with TVJ/TVT) or 1 V DC (with other basic units).

² Shut-off voltage 0.1 V DC or 0.5 V DC:

If there is a possibility or risk that the 0.1 V setpoint may not be undershot on a system (DDC output or long cable length), the shut-off voltage can be changed to 0.5 V with PC-Tool. This is only possible with signal voltage range 2 – 10 V DC.

Note on mode setting 0.1 V DC or 0.5 V DC

If there is a possibility or risk that the 0.1 V setpoint may not be undershot on a system (DDC output or long cable length), the shut-off voltage can be changed to 0.5 V with PC-Tool. This is only possible with signal voltage range 2 – 10 V DC.

Digital communication interface MP bus

General information

MP bus is not an open system, but manufacturer-dependent bus system for which Belimo and its partner companies provide components and software. Examples include the TROX XAIR-ZMO-MP zone module and software for the X-AIRCONTROL room control system, also the UK24xxx Belimo gateways and the fan optimiser.

MP bus allows you to have setpoint defaults and override controls preset and to read out damper positions and volume flow rates. As for the network, any topology can be used: star, ring, line, tree and hybrid topologies.

Neither special cables nor terminal resistors are required for the wiring, but the cable lengths are limited and depend on:

• the combined performance data of the connected MP devices
• whether AC 24 V or DC 24 V voltage is used
• the cable cross section

Example: MP bus with 5 LMV-D3-MP compact controllers on 24 V AC supply. Total power rating: 5 × 4 VA = 20 VA.

• A cable with 0.75 mm² cross section must not be longer than 28 m.
• A cable with 1.5 mm² cross section must not be longer than 54 m.

For more information on MP buses see the Belimo documentation at https://www.belimo.com.

VAV compact controller with MP bus

Control component BC0 is fitted with an MP bus communication interface and can be interconnected with up to 8 TROX/Belimo MP devices (damper actuators, valve actuators, VAV controllers) on a Belimo MP bus. The controller on the MP bus receives its control signal from the higher-level central BMS so that the volume flow rate setpoint can be achieved.

MP bus mode starts automatically as soon as the control component is assigned an MP address with a service tool. A standard Compact controller with an MP address becomes a bus-compatible system controller with a wide range of additional benefits.

MP bus requires that the U connection is used. The U connection can then no longer be used for analogue actual value feedback.