t.a.c. TAC 200, User Manual

Page: 20 / 40

TAC AB, Feb 2000
4:3
Special functions, P:16 -
TAC 200 User’s Manual
4.3 Control functions
TAC 200 has three separate control functions:
– one controller to limit the power consumption
– one controller for the room temperature
– one controller for the supply water temperature
The controller for the room temperatur is used only when there is a room
sensor. It is recommended to use a room sensor, as the room temperature
controller is very efficient in utilizing the heat stored in the building.
The influence of the outdoor temperature on the supply water temperature is
determined by the reset curve. SP
curve
is modified with SP
offset
, directly or via
the room temperature controller, by the variable Night setback or Morning
boost.
If the room temperature controller is active, SP
offset
will also be affected by the
requested setpoint value, the current room temperature and the min/max-
limits, if specified.
The resulting value may in turn be reduced by min/max-limits, resulting in the
SP value. This value is compared to SP
powlim
, the maximum allowable setpoint
calculated by the power limit controller.
The least of these is used as SP
supply
for the supply temperature controller.
The pump can be made to turn off at high outdoor temperatures or if SP
supply
has a low value.
Each of these functions is described in more detail in the following.
Reset
curve
Night setback
Morning boost
Time
pgm 1
Out-
door
temp.
SP dial
or
P:05/06
+
SP
room
REG
Room
temp.
MV
room
Min/max
limits
Room
temp.
(With room sensor)
(Without room sensor)
SP
offset
+
SP
curve
Min/max
limits
SP
powlim
SP
supply
SP
Least of-
function REG Supply
temp. Heating
unit
Supply
water
temp.
MV
supply
REG
Power
Pump
on/off
SP
maxpower
MV
power
Pump
Block diagram for the controllers of the TAC 200.