5:8 (16), 0-004-7516-1 (GB)
TAC AB, 1999-08-18
TAC Xenta 102 Handbook
Functional description
5.2.5 Control sequence with TAC Xenta 102-B
The controller changes between the heating and the cooling
sequence by a central command from the network. The heating
sequence is enabled when the variable nviApplicMode has the
value HVAC_HEAT. The cooling sequence is enabled when
nciAppOptions bit 2=1 or when the variable nviApplicMode has
the value HVAC_AUTO, HVAC_COOL or HVAC_NIGHT_-
PURGE. The diagram below shows the heating and the cooling
sequence for TAC Xenta 102-B:
5.2.6 Control sequence with TAC Xenta 102-EF and 102-VF
The air flow (cooling) and an electric heating coil or radiators for
TAC Xenta 102-EF or a heating water coil for TAC Xenta 102-VF
sequence controls the temperature. When the cooling sequence
should be run, the controller calculates an air flow setpoint to
VAV-Compact. Then the air flow controller sets the air flow to the
desired flow.
If the heating sequence should be run, the controller sets an
output to the heating coil, the thermo-actuators or the heating
valve. The air flow is set to a minimum value.
If the controller has a fan as an option, the fan is on when the
heating valve is open in TAC Xenta 102-VF or the electric
heating coil is on in TAC Xenta 102-EF.
The diagrams below illustrates the fan’s function for the
different control sequences.
Index Variable name
Description
14
nviApplicMode
Application mode input
24
nciAppOptions
Application options
Figure 5.3 Control sequence for TAC Xenta 102-B
Heating
Air flow
Cooling
Cooling demand
min.
max.
Changeover via
network variable
