Applications Guide Tracer Graphical Programming - Trane

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Chapter 3 Modifying the exhaust fan program
2. From the Edit menu, choose Delete. The block and any wires connected
to the block are removed from the design space.
Note:
To delete a block, you can also select the block and then press
the Delete key.
Adding a deadband
Add a Deadband block to the program. The deadband concept is very useful
in HVAC control applications. Its primary purpose is to minimize
equipment cycling. For the purposes of graphical programming, consider
three possible deadband configurations.
• Greater than (assume cooling)
• Less than (assume heating)
• Centered (assume cooling)
Greater than (assume cooling)
In the greater than (assume cooling) mode, the output of the deadband
function turns on when the measured value exceeds the setpoint. The output
remains on until the measured value falls below the setpoint point
minus the deadband (Figure 31).
Figure 31: Deadband function with greater than (assume cooling)
relationship
Less than (assume heating)
In the less than (assume heating) mode, the output of the deadband function
turns on when the measured value falls below the setpoint. The output
remains on until the measured value rises above the setpoint plus the
deadband (Figure 32 on page 33).
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