Delta Controls
Document Edition 4.2 Page 17 of 43
2. CONTROLLER OPERATION
Heating
Setpoint
-100%
Cooling
Heating
Day Setpoint
Cooling
Setpoint
Day
Differential
Deadband
Proportional BandProportional 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 ON at the same time
If the Input temperature is less than (Day Setpoint – (Day Differential + ½ Deadband)) then the
controller is in HEATING
If the Input temperature is greater than (Day Setpoint + (Day Differential + ½ Deadband)) then the
controller is in COOLING
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.
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