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FP-TB-1/2/3 Operating Instructions
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Minimizing Thermal Gradients
The most common source of thermal gradients, particularly for the
FP-TB-1 and FP-TB-2, is the heat generated by adjacent modules.
For example, placing an FP-TB-1 next to an FP-1000 network
module can create more than a 1 °C thermal gradient. Mounted
thermocouple modules can be separated from the higher-power
modules by the lowest-power modules in your system or by the
FieldPoint Bus Extender Cable (part number 185576-15). This
precaution is generally not necessary with the FP-TB-3.
Hot or cold air draft can be another source of thermal gradients.
It is usually best to avoid having air blowing directly on the
terminals, although circulating air around other nearby
components may help them dissipate their heat and cause them
to be less of a source of thermal gradients on the terminal base.
Thermocouple wire also has the potential to be a significant source
of thermal gradients. Even the FP-TB-3 can be susceptible to these
errors. Heat or cold may be directly conducted to the terminal
junction by the thermocouple wire. If the thermocouple wires,
or objects they are in contact with, such as wiring ducts, near the
terminal base are at a different temperature than the terminals,
the wires transfer heat to or from the terminals and cause thermal
errors. To minimize these errors, follow these guidelines:
•
Use small-gauge thermocouple wire. Smaller wires transfer
less heat.
•
Run thermocouple wires together near the terminal base to
keep them at the same temperature.
•
Avoid running thermocouple wires near hot or cold objects.
Specifications
The following specifications are typical for a range of
–40 to 70 °C, unless otherwise noted.
Installation
Terminal wiring ................................ 16–26 AWG copper
conductor wire with 7 mm
(0.28 in.) of insulation
stripped from the end
1
1
Use only copper conductor wire unless you are working with a sensing
device, such as a thermocouple, that requires a different kind of wire.
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