Applications Guide Tracer Graphical Programming - Trane

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Writing the mode and setpoints program
Figure 128: Heat/Cool mode decision
Determining the heat/cool mode
Now that you have all the setpoints you need, start to use them. What do
you know from the sequence of operation about determining the active
mode, heating or cooling?
• In any occupancy mode, the heat/cool decision is based on the effective
occupied or occupied standby cooling and heating setpoints.
• The air handler changes to cooling if the space temperature exceeds
the effective cooling setpoint plus 1°F.
• The air handler changes to heating if the space temperature falls
below the effective heating setpoint minus 1°F.
UsetheTGPmoduleinFigure128tomaketheheat/cooldecision.Usea
Deadband block to switch between heating and cooling modes and wireless
connections to provide the effective cooling and heating setpoints calculated
in another part of the program. Store the heat/cool mode in a
binary variable for use in another program.
Figure 129: Completed modes and setpoints program
Offset calculation
The mode and setpoints program completes the VAV air-handling unit.
Compile and download this final program (Figure 129) to the controller.
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