5:6 (16), 0-004-7516-1 (GB)
TAC AB, 1999-08-18
TAC Xenta 102 Handbook
Functional description
5.2.4 Setpoint calculation
Zone temperature setpoints
nciSetpoints defines temperature setpoints; heating setpoint
comfort mode, cooling setpoint comfort mode, heating setpoint
economy mode, cooling setpoint economy mode.
The smallest accepted deviation between the heating and cooling
setpoints is 0,5 °C, and the heating setpoints must be lower than
the cooling setpoints. If the heating setpoints are higher or equal
to the cooling setpoints, the controller resets the heating setpoint
to 0,5 °C lower than the cooling setpoint. Table 5.2 shows accept-
ed values and default values for the four temperature setpoints in
nciSetpoints.
The setpoints for comfort and economy mode are basic
setpoints, which can be changed with nviSetpoint,
nviSetPntOffset and the setpoint knob.
Calculation
The current setpoint, nvoEffectSetpt, depends on the current op-
eration, nvoUnitStatus, the desired operation mode, nviApplic-
Mode, and nviSetpoint, nviSetpntOffset, nciAppOptions, nciSet-
points and a possible local setpoint adjustment via the wall
module. Figure 5.2 shows an overview over the relation
between the variables used for setpoint calculation.
nviSetpoint is used to allow the temperature setpoints in comfort
and economy mode to be changed via the network. If there is a
valid value on nviSetpoint, the controller calculates the setpoints
for comfort and economy mode with method A or method B
(the methods are described in Appendix A). The choice of
method is made via nciAppOptions, bit 9. If bit 9=0 method B is
used, and if 9=1 method A is used. If there is no valid value on
nviSetPoint, no recalculation of the temperature setpoints in
nciSetpoints is made.
Setpoint
Min.
Max.
Default
Cooling setpoint comfort
10 °C
35 °C
23 °C
Heating setpoint comfort
10 °C
1
35 °C
21 °C
Cooling setpoint economy
10 °C
35 °C
25 °C
Heating setpoint economy
10 °C
1
35 °C
19 °C
Table 5.5 Setpoints in nciSetpoints.
1
If the cooling setpoint is 10 °C, the heating setpoint is set to 9,5 °C.