MicroLogix 1200 RTD/Resistance Input Module
11
Publication 1762-IN014B-EN-P - July 2013
2-Wire Potentiometer Interconnection
IMPORTANT
Using 2-wire configurations does not permit the module to compensate for
resistance error to do lead wire length. The resulting analog data includes
the effect of this uncompensated lead wire resistance. The module
continues to place the uncompensated analog data in the input data file, but
the open-circuit status bit (OCx) is set in word 4 of the input data file for
any enabled channel using a 2-wire configuration. These status bits may be
used in the control program to indicate that the analog data includes error
due to uncompensated lead wires. See page 16 for a detailed discussion of
the open-circuit status bits.
EXC 2
SENSE 2
RTN 2
NC
EXC 2
SENSE 2
RTN 2
NC
Cable Shield (to Ground)
Potentiometer
RTD EXC
Return
Cable Shield (to Ground)
Potentiometer
RTD EXC
Return
Belden 9501 Shielded Cable
Belden 9501 Shielded Cable
TIP
The potentiometer wiper arm can be connected to either the EXC or
return terminal, depending on whether you want increasing or decreasing
resistance.
