LON-WA TDC

Functional description

Adjustable air terminal devices with actuators are used to achieve the best possible air distribution in high and large rooms with changing thermal loads. Type LON-WA TDC control modules control actuators based on the supply air to room air difference.

Supply air temperature and room air temperature are measured with external sensors and transmitted as voltage signals or LonWorks network variables Characteristic curve values translate into discharge angles, and the actuators are set accordingly.

Override functions are available to set various operating modes.

The program sequence of the control module includes a watchdog and a heartbeat function to monitor and maintain operation.

Operating modes

Temperature difference control

• Calculation of the supply air to room air temperature difference
• Discharge angle corresponds to characteristic
• Standard operating mode if temperature difference control has been configured
• No override functions

Variable operation

• Direct control of the discharge angle with a voltage signal (AI1) or with a network variable (nviManCntrl)
• Temperature difference is neglected
• Standard operating mode if variable operation has been configured
• No override functions

Cooling

• Override function, the discharge angle is reduced to the minimum
• Minimum angle is defined with SCPTminRnge (nvoActuatorPos)
• Set via DI1 or nviDI1_State

Isothermal operation

• Override function, the discharge angle is neutral
• Neutral position is defined with SCPTdischargeAirHeatingSetpoint
• Set via DI2 or nviDI2_State

Heating

• Override function, the discharge angle is increased to the maximum
• The maximum angle is defined with SCPTmaxRnge (nvoActuatorPos) and SCPTdischargeAitCoolingSetpoint
• Set via DI3 or nviDI3_State

Heating up

• Override function, the discharge angle is reduced to the minimum
• Set via DI4 or nviDI4_State

Inputs

Two analogue inputs

• Analogue inputs with configurable characteristic for signalling the supply air temperature and the room air temperature
• With variable operation: Analogue input for signalling the setpoint discharge angle

Four digital inputs

• Digital inputs for volt-free switches
• Override functions for variable operation, cooling, heating and isothermal operation

Outputs

One analogue output

• Analogue output with configurable characteristic for signalling to modulating actuators

Two digital outputs

• Digital outputs for signalling to heating/cooling actuators, 2-wire control (3-point)

Interface to the central BMS

• Actual operating values and fault messages of the control module are transferred via the network
• Supply air temperature, room air temperature, discharge angle
• Status of the digital inputs and voltage at each analogue input

Description of network variables (SNVT)

All variables and parameters are based on standard network variables (SNVT); this ensures integration of LON-WA TDC with a LonWorks network.

Operating mode default setting

• Input variables nviDI1_State, nviDI2_State, nviDI3_State, nviDI4_State for operating modes
• nviDI1_State has the highest LON priority
• nviDI4_State has the lowest LON priority
• The valid binding of an input variable results in a valid operating mode default setting
• The invalid binding of an input variable does not result in an operating mode default setting in LON

Data points

Configuration parameters