Rockwell Automation T3420AF ICS Regent Analog Input Modules - Manual (Page 18)

Analog Input Modules (T3420A, AF)
1 8
Industrial Control Services
A 1K Ohm resistor isolates the grounding terminal on the
input termination block from AGND on the input module, and
prevents large currents from flowing through the module
because of potential differences in the ground terminal of the
upper input termination block with respect to the lower input
termination block. The common reference point on the input
termination block goes into a separate input pin on the 10-pin
barrier strip and in single-ended measurements becomes the
common reference for all of the signals on the input
termination block. For the non-triplicated module
configuration, the three distinctly different types are
described below.
Termination blocks are available in a set of two termination
blocks, one for the upper I/O terminals and one for the lower
I/O terminals. These sets are listed below.
Voltage Mode Input Termination Block Sets
(T3325-V and -VJ)
These input termination block sets are used for both single-
ended and differential voltage measurements. Model
T3325-V is used for a single input module. Model T3325-VJ
has additional jumper wires to connect the signals to
redundant input modules installed in adjacent I/O slots.
The proper wiring connections for the voltage mode
termination blocks are shown in Figures 10 and 11.