Thermalert ET Series Operator's Manual
2-3
2.1.5 Wiring
Sensor power will connect to 12 VAC, which should be as “noise free” as possible. Do
not ground the secondary of the transformer.
CAUTION
When routing the interface cable, avoid paths running near sources of
interference such as large electric motors, welders and generators.
Note that when using thermocouple output models, be sure to use the appropriate
thermocouple wire.
2.1.6
Multiple Sensors
There are two types of interfacing to consider when connecting more than one sensor
to a controller (or other device): differential and single-ended. Differential configura-
tions are preferred over single-ended since they are less susceptible to noise. This
advantage, of course, must be weighed against the disadvantage of using additional
input positions. See Figure 2-2 for thermocouple outputs; the longer the cable, the
more likely differential hook-ups should be used.
Figure 2-2: Multiple Sensors