XB0

A closed control circuit for regulation of the volume flow rate, i.e. measuring - comparing - adjusting, is characteristic of air terminal units.
The volume flow rate is measured via the differential pressure (effective pressure). This is done via a differential 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 volume flow rate (q_vNom).
The volume flow rate setpoint value is specified by a higher-level controller (e.g. room temperature controller, air quality controller, central BMS). Variable volume flow control results in a value between qv_min and qv_max. It is possible to override the room temperature control, e.g. by a complete shut-off of the duct.
The controller compares the volume flow rate setpoint value to the actual value and controls the integral actuator according to the system deviation.

Compact controllers for VAV terminal units

Compact controller XB0, 227V-024-10-DD3

Compact controller XB0, TR0V-024T-05I-DD15

Release of a test function

Pressing the LED push button for > 2 seconds activates the test drive.

Description of status and error messages via LED flashing signal for TROV-024T-05l-DD15

Flashing signal of LED button	Flashing signal in words	Status
	LED off	No supply voltage
	LED lights up permanently.	Regulated. Signalled as long as the actuator does not rotate to readjust the setpoint value.
	LED flashes 1 time in a 2-second interval.	Setpoint value or override control position not yet reached.
	LED flashes 2 times in a 2-second interval.	Override control position reached.
	LED flashes once briefly at 2-second intervals.	Synchronisation drive after Power Up
	LED flashes once briefly at 2-second intervals.	Test mode activated
	LED flashes 2 times in quick succession at 2-second intervals.	Overpressure sensor (overpressure)
	LED flashes 2 times in quick succession at 3-second intervals.	Actuator overload detected (block)
	LED flashes 4 times in quick succession at 2-second intervals.	Inform TROX service technicians

The flashing signal always describes a 2-second interval. 1 = LED lights up, 0 = LED does not light up.

Product details

Analogue interface 0 – 10 V or 2 – 10 V DC (operating mode V, F)

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

• The set signal voltage range always applies equally for setpoint value and actual value signals.
• The signal voltage range is pre-set in the factory according to the order code entries.
• The signal voltage range can be adjusted by others with an adjustment device

Setpoint value default setting

In the operating mode V (variable operation), the setpoint value is specified with an analogue signal on terminal Y. 

• The selected signal voltage range 0 – 10 V or 2 – 10 V DC is assigned to the volume flow rate range q_vmin – q_vmax .
• Volume flow rate range q_vmin – q_vmax is preset at the factory according to the order code
• Subsequent adjustment of q_vmin or q_vmax is possible with adjustment device
• In operating mode F (constant value mode), an analogue signal at terminal Y is not required
  The volume flow rate constant value set by q_vmin is controlled
• Volume flow rate q_vmin is preset at the factory according to the order code
• Subsequent adjustment of q_vmin is possible with adjustment device

Actual value as feedback for monitoring or tracking control

• The actual volume flow rate measured by the controller can be captured as a voltage signal at terminal U
• 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 blade position
• The selected signal voltage range, 0 – 10 V DC or 2 – 10 V DC, is then mapped to the damper blade position as a percentage value between 0 % (CLOSED) and 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 P_vmin, control q_vmax, damper blade in the OPEN position or damper blade CLOSED.

Override control via signal input Y

With appropriate wiring on the signal input Y, the override controls can be activated according to the connection diagrams via wiring with external switch contacts/relays. OPEN and CLOSED are only available if the controller is supplied with alternating current (AC).

Override control CLOSED via control signal Y

• With signal voltage range 0 – 10 V DC: CLOSE is activated if q_vmin = 0 and the control signal on Y < 0.5 V DC
• With signal voltage range 2 – 10V DC: CLOSE is activated if control signal Y < 0.8 DC (*1)

(*1) 0.8 V DC = factory setting

Override control for diagnostic purposes

• For test purposes, the override control can also be activated via the service tools (adjustment device, PC software).

Prioritisation of various setting options

• High priority: settings via the service connector (adjustment device, PC software) for test purposes
• Low priority: settings via Y signal input of the controller

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
• 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
• Remove the terminal cover of the control component only temporarily for wiring (applies only to XB0 for TVE).