XS0-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.

Product details

Modbus mode (order code, operating mode M)

For smooth data exchange in the Modbus RTU network, the communication parameters and user address must be set for the Modbus interface.

The interface offers standardised Modbus register access to the available data points via the functions ReadHoldingRegister (3) and WriteSingleRegister (6).

Setpoint value default setting

• In the operating mode M, the setpoint defaults as a percentage [%] in the Modbus register 0.
• The transferred percentage value refers to the volume flow rate range specified by qvmin – qvmax.
• Volume flow rate range qvmin – qvmax is set at the factory as per the order key data
• Subsequent adjustment of qvmin or qvmax is possible in the setup menu on the display, with the adjustment device or using the Modbus interface or X-AIRCONTROL.
  
  

Actual value as feedback

• The actual volume flow rate can be called up using the display, adjustment device or X-AIRCONTROL
• In addition to the volume flow rate actual value, further information can be read out via X-AIRCONTROL
  
  
  

Override control options

For special operating situations, the volume flow controller can be put in a special operating mode (override control).

The following modes are possible: control qvmin, control qvmax, damper blade in the OPEN position or damper blade CLOSED.

• This is set via X-AIRCONTROL.

Override control for bus timeout monitoring:

• When there is a failure in communication, the controller executes the last saved status as a result of its factory setting. Using suitable software, the factory setting can be changed via the Modbus register 108. Each communication resets the timeout of the bus failure monitoring.

Override controls for diagnostic purposes

Activation of the diagnostic menu on the display of the controller or via X-AIRCONTROL.

Prioritisation of various default setting options

Defaults via service tools are prioritised over Modbus defaults.

• Highest priority: defaults via the service connector (adjustment device, PC software) for test purposes
• Lowest priority: defaults via Modbus 1 or the diagnostic menu on the controller

Compact controllers for VAV terminal units

Compact controller TROVM-024T-05I-DS10-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 XS0-J6. For this reason, the configuration register (interface mode) must not be changed by others. To use an analogue interface, the variant XS0 is 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: For the control component XS0-J6, only the register value 2 is practical, as the analogue input and the analogue feedback signal are not available on the connection socket.

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
• For the variant with RJ12 connection socket, only the Modbus interface configuration is suitable
• Adjustment option for Modbus communication settings (address, baud rate, stop bits, parity)

Diagnosis

• Activation of a test run
• Activation of override controls Open, Closed, q_vmin, q_vmax, motor stop (note prioritisation)

Commissioning

• After installation, wiring and connection of the supply voltage
• Set the Modbus communication parameters via the integral display, the air terminal unit is then ready
• Setpoint value default setting via X-AIRCONTROL
• 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 socket cover 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