Configured for current sourcing signal acquisition in Allen-Bradley PLC-5 systems, the Allen-Bradley 1771-NIS/B (1771-NIS Analog Input Module) provides direct physical/electrical execution.
Suffix Breakdown & Model Matrix
1771: Universal I/O chassis-based module platform for PLC-5 automation architectures.
NI: Analog input module design classification.
S: Sourcing current channel configuration.
B: Revision hardware series designation.
Hardware Specifications
Parameter
Specification
Model
1771-NIS/B
Brand
Allen-Bradley
Origin
USA
Weight
1.81 lbs (0.8 kg)
Dimensions
2.0 x 6.0 x 10.0 in (5.1 x 15.2 x 25.4 cm)
Operating Temp
0 to 60 deg C
Power Consumption
Standard 1771 backplane bus current draw
Input Channels
8 isolated channels
Signal Range
4-20 mA current
Signal Type
Isolated current sourcing
High-Density I/O Isolation and Backplane Determinism
The 1771-NIS/B module features channel-to-channel galvanic isolation to prevent ground loops across sensitive 4-20 mA current loops. Designed to maintain signal integrity within EtherNet/IP and remote I/O deterministic networks, the module conditions analog field signals directly for the PLC-5 processor without degrading backplane bus communication velocity or introducing channel cross-talk.
Frequently Asked Questions
Q: Does the 1771-NIS/B module support voltage inputs directly?
A: No, the 1771-NIS/B is configured exclusively for 4-20 mA current sourcing signals across its 8 isolated channels.
Q: How does channel-to-channel isolation benefit field instrumentation signals on the 1771-NIS/B?
A: Channel-to-channel isolation eliminates ground potential differences between field transmitters, protecting internal analog-to-digital converters and preserving conversion accuracy.
Field Installation Guidelines
Turn off all backplane power to the 1771 chassis and de-energize external 4-20 mA current loops before module insertion or extraction.
Align the module circuit card with the top and bottom chassis slot rails, pushing firmly until the locking lever fully engages.
Terminate shielded twisted-pair signal cables to the field wiring arm, grounding cable shields at one end only to prevent loop current interference.
Separate analog input wiring from AC power lines and high-voltage motor circuits to avoid electromagnetic noise pickup.
