Applications Guide Tracer Graphical Programming - Trane

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Chapter 4 Cooling tower with two-speed fan example
Figure 55: Sump temperature alarm logic
Indicating an alarm for any temperature sensor failure
You want to indicate an alarm when any temperature sensor fails. These
sensor-input temperatures include Sump Temp, Supply Temp, Return
Temp, and Outdoor Air Temp. Add a Fail block to monitor temperature
sensors for failure and make the appropriate connections. Because there
are four temperatures, use one Fail block and expand it to accommodate
all four temperature inputs.
➤ Expandable blocks
Several blocks expand to accommodate a number of inputs. Each of
the properties dialog boxes for these blocks allows you to specify the
number of inputs. The minimum number of inputs depends on the
block. All expandable blocks expand to a maximum of eight input
ports.
To indicate an alarm for any temperature sensor failure:
1. Place a Fail block in the design space.
2. Double-click the Fail block. The Fail Properties dialog box appears
(Figure 56).
Figure 56: Fail Properties dialog box
3. In the Number of Inputs field, type:
4
4. Click OK. The Fail block changes to include four input ports.
5. Connect the Sump Temp, Supply Temp, Return Temp, and Outdoor
Air Temp input blocks to the Fail block (Figure 57 on page 59).
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