XM0-J6

VAV terminal units control the volume flow in a closed loop, i.e. measurement - comparison - correction. The volume flow rate is measured via the differential pressure (effective pressure). This is done using a differential pressure sensor. An integral differential pressure transducer converts the effective pressure into a voltage signal. The volume flow rate actual value is available as a data point. The factory setting is such that 100 % correspond to the nominal volume flow rate (q_vnom). The volume flow rate setpoint value defaults 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_vmax. 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 accordingly.

Compact controllers for VAV terminal units

Compact controller TROVM-024T-05I-DD15-MB with connection socket RJ12

Interface configuration of control component

The communication interface of the control component is pre-set to Modbus at the factory for use with the X-AIRCONTROL zone module. Only the Modbus address must be adjusted by others for supply air or extract air. For other applications, data transmission speed and format must be adapted according to the network environment. Using the analogue interface is not possible in combination with the connection socket RJ12 of the variant XM0-J6. For this reason, the configuration register 122 (interface mode) must not be changed by others. To use an analogue interface, the variant XM0 must be used.

Communication interface Modbus RTU (operating mode M)

* Factory setting: Modbus address 1

R = Register can be read

R,W = Register can be read and written

RAM = Volatile register value

EEPROM = Register value not volatile, but saved permanently (max. 1 million write processes)

Detailed information on register 122 (communication interface setpoint/actual value - Interface Mode)

Note: Only register value 2 makes sense for control component XS0-J6 because the connection socket cannot be used as analogue input or for an analogue feedback signal.

Detailed information on register 568 (Modbus communication parameters)

** Factory setting: Modbus communication parameters

Range of display functions

Display functions

• Volume flow rate actual value (unit optionally m³/h, l/s, cfm)
• 3-character display with positional notation
• Status and error display for various operating states, including display of activated override control, display of diagnostic function

Parameter setting

• Adjustment option for the unit of the volume flow rate display m³/h, l/s, cfm
• Adjustment option for the operating range q_vmin, q_vmax
• Selection of the interface configuration Modbus or analogue including signal voltage range 0 – 10 V or 2 – 10 V DC
• Adjustment option for Modbus communication settings (address, baud rate, stop bits, parity)

Diagnosis functions

• Activation of a test run
• Activation of override controls Open, Closed, q_vmin, q_vmax, motor stop (note prioritisation)
• Display of the voltage value on the analogue input

Commissioning
After installation, wiring and connection of the supply voltage

• When using the Modbus interface: set the Modbus communication parameters using the integral display, the air terminal unit is then ready
• Setpoint value default setting via Modbus register
• When using the analogue interface: air terminal unit is immediately ready for use
• Comply with volume flow rate control range from 4 – 100 % of q_vnom; do not set a volume flow rate which is below the minimum flow rate of the control unit
• Only briefly remove the protective cap of the control component during wiring

Use and description of the display

Pressing the LED push button (< 3 s) selects the next menu item ① - ⑥. The selected menu item can be changed by pressing the LED push button for more than 3 s. Changing is done with the rotary selector switch. Pressing the LED push button again (< 3 s) confirms the selected value. If no entry is made for >= 60 s, the system returns to menu item 1.

Table 1: Description of the menu items

Description of status LEDs and error messages

LED flashing signal	Status	Display
	No supply voltage connected.
	Inform TROX service technicians
	Actuator overload detected (block)
	Synchronisation after Power Up
	Test mode activated
	Overpressure sensor (overpressure)
	Setpoint value or override control position not yet reached (display changes between e.g. Hi = High and actual value)
	Override control position reached (display changes between e.g. Hi = High and actual value)
	Normal operation with the setpoint being maintained. Signalled as long as the actuator does not rotate to readjust the setpoint value.

The flashing signal appears every 2 seconds. 1 = LED is illuminated, 0 = LED is not illuminated

Product details

Modbus operation (operating mode M in the order code)

A smooth exchange of data in the Modbus RTU network (network by others) requires that the communication parameters and the user address for the Modbus interface are set.
The interface offers standardised Modbus register access to the available data points by means of the ReadHoldingRegister (3) and WriteSingleRegister (6) functions.

Setpoint value default setting

• With operating mode M, the setpoint value defaults as a percentage [%] in Modbus register 0.
• The percentage value refers to the volume flow rate range qvmin – qvmax
• Volume flow rate range q_vmin – q_vmax is set in the factory according to the order code
• q vmin or q vmax can be adjusted at a later stage using the setup menu (display), an adjustment device, the Modbus interface or X-AIRCONTROL

Actual value retrieval

• The volume flow rate actual value can be retrieved using the display, an adjustment device or X-AIRCONTROL
• X-AIRCONTROL allows you to retrieve also other data in addition to the volume flow rate actual value

Override control

If necessary, and depending on the situation, the volume flow controller can be set to a special operating mode (override control)
The following modes are available: control based on qvmin, control based on qvmax, damper blade OPEN or damper blade CLOSED

• Values default via X-AIRCONTROL
• Override control for bus timeout monitoring:
• If the communication fails, the controller goes into the status that was last saved (factory setting) Using suitable software, the factory setting can be changed in Modbus register 108 Any communication will reset the timeout of the bus failure monitoring system

Override controls for diagnosis
You can enable these override controls on the diagnosis menu (controller display) or with X-AIRCONTROL

Priority of various default setting options
Service tool defaults have priority over Modbus defaults

• Highest priority: defaults coming from a service tool (service connector), e.g. adjustment device or PC software, for test purposes
• Lowest priority: defaults coming from Modbus 1 or the diagnosis menu on the controller