Applications Guide Tracer Graphical Programming - Trane

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Chapter 2 Writing the exhaust fan program
Aligning blocks
Align the Equip Rm Space Temp block, the 85.0 constant block, and the
Equip Rm Temp Setpoint (°F) comment blocks.
To align blocks:
1. Select the Equip Rm Space Temp block, the 85.0 constant block, and
the Equip Rm Temp Setpoint (°F) comment block. The last block
selected is the reference block, so all of the selected blocks align
according to the position of the last block selected. The selected blocks
are outlined in yellow.
2. From the Alignment menu, choose Left. The blocks align left
(Figure 20).
Figure 20: Blocks aligned left
Adding a Compare block
Compare blocks compare two analog values and output a binary true or
false value, providing an analog to binary conversion. In this case, you
want to add a Greater Than block to the program.
Use the Greater Than block to compare the space temperature with the
setpoint. If the space temperature is greater than the setpoint, the output
of the Greater Than block is true. Otherwise, if the space temperature is
less than or equal to the setpoint, the output of the Greater Than block is
false.
➤ Inputs to a Compare block
For some Compare blocks, the input port you choose for a value is
important. For example, the Greater Than block compares the top
input-port value to determine whether it is greater than the bottom
input-port value. Remember this relationship when working with the
Greater Than, Greater Than or Equal, Less Than, and Less Than or
Equal blocks.
To add a Compare block:
1. From the Blocks menu, choose Compare. From the Compare menu,
choose Greater-Than.
2. Click in the design space to place the Greater Than block (Figure 21
on page 23).
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