Rockwell Automation T3420AF ICS Regent Analog Input Modules - Manual (Page 21)

Analog Input Modules (T3420A, AF)
P D - 6 0 2 3 M a r - 0 6
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Single-Ended Current Mode Input Termination Block Sets
(T3325-S and -SJ)
These input termination block sets have high-precision
resistors (250 ohms each, 0.05% initial tolerance, 5 ppm/
° C
drift) onboard to convert single-ended current loop signals to
voltage signals that can be directly interfaced to the analog
input module. Two terminals per input channel are provided
where one terminal connects the active lead of the single-
ended current pair to the 250 ohm resistor and the other
terminal connects to the analog signal return. All of the
analog signal returns are commoned on the termination block
and connect to the analog input module signal AREF.
Model T3325-S is used for a single input module. Model
T3325-SJ has additional jumper wires to connect the signals
to redundant input modules installed in adjacent I/O slots.
The proper wiring connections for the single-ended, current
mode termination blocks are shown in Figure 12. The figure
also illustrates typical marshaling terminal connections for
supplying loop power from a 24 VDC power source.
Differential Current Mode Input Termination Block Sets
(T3325-D and -DJ)
These input termination block sets service differential
current-loop inputs. Each termination block has precision 250
ohm resistors (as above).
Model T3325-D is used for a single input module. Model
T3325-DJ has additional jumper wires to connect the signals
to redundant input modules installed in adjacent I/O slots.
The proper wiring connections for the differential current
mode termination blocks are shown in Figure 13. The figure
also illustrates typical marshaling terminal connections for
supplying loop power from a 24 VDC power source.