Applications Guide Tracer Graphical Programming - Trane

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Writing the cooling tower fan module
Figure 81: Adding the fan at high speed
Transitioning the fan based on time
To implement the time delay, use the Delay on Start block. The on/off control
input of the Delay on Start block comes from the output of the And
block. The delay countdown begins when the fan starts at low speed. Use
another And block to ensure that both of the previously mentioned criteria
apply to control of the binary output, Fan High.
To transition the fan based on time:
1. Place a Delay on Start block in the design space and assign its units
to seconds.
2. Place a Constant block in the design space and assign the value 30.0
to it.
3. Place another And block in the design space.
4. Connect the first And block to the On/Off Control port of the Delay on
Start block.
5. Connect the 30.0 constant block to the Delay port of the Delay on
Start block.
6. Connect the Delay on Start block and the second Deadband block to
the second And block.
7. Connect the second And block to the Fan High output block.
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