...
Resistance
...
and
...
RTD
...
Input
...
Mode
Resistance and RTD Readings
The FAC-2100
...
uses
...
a
...
three-wire
...
technique
...
to
...
read
...
resistors
...
and
...
RTD
...
sensors.
...
This
...
technique
...
involves
...
having
...
one
...
wire
...
(signal)
...
connected
...
to
...
one
...
end
...
of
...
the
...
resistor
...
and
...
two
...
wires
...
(common)
...
be
...
connected
...
to
...
the
...
other
...
end.
...
The
...
advantage
...
of
...
this
...
technique
...
is
...
that
...
the
...
resistance
...
associated
...
with
...
the
...
cable
...
negated
...
and
...
only
...
the
...
resistance
...
of
...
the
...
sensor
...
element
...
is
...
measured.
...
Wiring
...
Diagram
...
The
...
following
...
figure
...
shows
...
the
...
typical
...
wiring
...
for
...
a
...
resistor
...
or
...
RTD:
Example Analog Input Wiring for Reading a Resistor or RTD
If the reading error associated with the resistance of the cable is not significant for your system (or can be compensated for using some other means) then it is possible to use a two wire cable and short the ground and AIN- pins together in the FAC-2100 connector.