A-B Allen-Bradley

Full Name: 16 Point Analog Current Input Module

The 1746-NI16I is a dedicated analog input module designed for Allen‑Bradley SLC 500 modular PLC racks. Its core functions are described as below:

1. Industrial Standard 4–20mA Current Signal Acquisition This module provides 16 independent analog current input channels, exclusively designed for industry-standard 4–20mA current transmitters, including pressure, temperature, level, flow and valve position sensors. The 4mA signal corresponds to the minimum measurement value and 20mA to full scale. Current signals feature strong anti-interference performance and support long-distance field wiring.
2. High-Precision Analog-to-Digital (A/D) Conversion It converts continuous 4–20mA analog current signals from field transmitters into digital values recognizable by the SLC 500 CPU, then transfers digital data to PLC memory for program calculation, logic judgment and data visualization. Built-in isolation and filter circuits suppress electromagnetic noise generated by motors and variable frequency drives to eliminate unstable signal fluctuation.
3. High-Density Multi-Channel Design to Save Rack Slots One single module integrates 16 input points, which greatly reduces occupied rack slots compared with 4-point or 8-point analog modules. It is ideal for applications with dense analog measuring points, such as assembly lines, water treatment systems, HVAC and small chemical equipment, cutting hardware and wiring investment.
4. Hazardous Location & Wide Industrial Environmental Compatibility Certified by UL and CE standards, it can be deployed in Class I Division 2 hazardous locations. It adapts to standard industrial cabinet operating temperatures and draws power directly from the SLC 500 backplane 24VDC power supply without external analog power sources.
5. Support PLC Monitoring & Closed-Loop Automatic Control Digital values converted from analog signals can be scaled, set with high/low limit alarms and used for PID regulation inside SLC 500 ladder logic programs. Typical applications include valve flow regulation and heating/cooling equipment temperature closed-loop control.
6. Channel Fault Detection & Diagnostic Feedback The module features open-wire detection. If a transmitter cable breaks or a sensor malfunctions, the corresponding channel digital reading will exceed the standard 4–20mA range. The PLC program can identify circuit failures and trigger system alarms, while a faulty single channel will not disrupt signal collection of the other 15 channels.