Allen-Bradley 1746-NIO4I SLC 500 Combination Analog I/O Module

Description

The Allen-Bradley 1746-NIO4I is a 4-channel combination analog input and output module designed for use with SLC 500 programmable logic controllers. The module integrates two differential analog input channels and two analog current output channels into a single-slot architecture to lower system cost and reduce chassis size. Each input channel can be individually configured for voltage (-10 to +10V dc) or current (-20 to +20 mA) signal operation via circuit board DIP switches. Inputs feature 16-bit resolution with low-pass digital filtering (10 Hz at 3 dB) for electrical noise immunity. Outputs provide 14-bit converter resolution across a 0 to 21 mA range. Backplane isolation protects control electronics from field-side electrical interference.

Features

• Compact Combination Architecture: Integrates 2 analog inputs and 2 analog current outputs within a single-slot 1746 chassis layout.
• High Signal Resolution: Features 16-bit input A/D conversion and 14-bit output D/A conversion.
• Configurable Input Signals: DIP switches on the circuit board permit channel-by-channel selection between voltage (-10 to +10V dc) and current (-20 to +20 mA) inputs.
• Noise Immunity: Low-pass filtering (10 Hz at 3 dB) delivers 105 dB common-mode rejection at 60 Hz.
• Removable Terminal Block: Includes a 1746-RT28 terminal block to allow module replacement without disconnecting field wiring.
• Automatic Data Updates: Executes end-of-scan I/O updates automatically without requiring specialized ladder program commands.
• Electrical Isolation: Features backplane-to-field isolation rated for 500V dc continuous.

Applications

• Process variable monitoring and loop control (e.g., flow, pressure, temperature transmitters).
• Actuator and control valve positioning using 0 to 20 mA or 4 to 20 mA current loops.
• Distributed industrial automation within SLC 500 PLC chassis installations.

Technical Specifications

Connections/Interfaces

Installation Guidelines

• Power Safety: Disconnect backplane power to the SLC 500 chassis and field devices before installing or wiring the module.
• Module Placement: Insert the module into any available I/O slot in a 1746 chassis, except slot 0 (reserved for the CPU).
• Input DIP Switch Setup: Set internal DIP switches S1 and S2 to CLOSED for current inputs or OPEN for voltage inputs prior to installation.
• Cable Selection & Shielding: Use Belden 8761 shielded twisted-pair cable. Connect the cable shield drain wire to earth ground at one end only.
• Wiring Routing: Keep analog signal wiring isolated from high-voltage power cables and inductive loads to mitigate noise interference.
• Terminal Screw Torque: Fasten terminal screws to a torque rating between 0.7 and 0.9 Nm (6 to 8 in-lbs) to avoid stripping.
• Unused Channels: Jumper unused input channels to ANL COM to prevent signal floating. Do not jumper unused current output terminals.

Compliance and Certifications

• UL 508 Listed
• CSA 22.2 No. 142 Approved (Class I Division 2 Hazardous Location)
• CE Compliant (for applicable directives)