DNT-T103 & DNT-T221 Application Guide
Page 16 of 41
Document Edition 4.1
2.
C
ONTROLLER
O
PERATION
Heating
Setpoint
-100%
Cooling
Heating
Day Setpoint
Cooling
Setpoint
Day
Differential
Deadband
Proportional Band
Proportional Band
Controller
Output
(Cooling)
0%
100%
Controller
Output
(Heating)
0%
Temperature
NORMAL CONTROLLER ACTION
Deadband is a span of 0.2 around setpoint (heating or cooling) over which neither heating nor cooling
takes place.
Here are a few rules and restrictions to how the internal Loop Controller functions:
•
Heating and Cooling will not be O
N
at the same time
•
If the Input temperature is less than (
Day Setpoint
– (
Day Differential
+
½ Deadband
)) then the
controller is in H
EATING
•
If the Input temperature is greater than (
Day Setpoint
+ (
Day Differential
+
½ Deadband
)) then the
controller is in C
OOLING
•
If the Input temperature is between these two extents for Heating and Cooling, then the controller is
in
A
null zone
For all control applications (except when
Box Mode
is heating in VAV or VVT) the
Controller Status
(AV14) will modulate from -100 to 100% and sequence any necessary output stages. A value of 0 to
100% represents heating output from the controller, while a value of 0 to -100% represents cooling
output from the controller.
