Allen-Bradley 1756-IM16I 16 Channel Isolated AC Input

Product Overview

The Allen-Bradley 1756-IM16I is a premium, heavy-duty 16-point isolated AC digital input module belonging to the high-performance ControlLogix automation platform. Engineered for challenging industrial environments with diverse electrical grids, this module provides complete point-to-point isolation across all 16 channels, operating within a nominal voltage category of 240 Volts AC (159 to 265 VAC range). Weighing approximately 0.30 kg (0.66 lbs), this chassis-based processor card monitors high-voltage field statuses, executes precise Change-of-State (COS) tracking, and protects the core PLC backplane from dangerous multi-phase cross-faults or erratic voltage spikes.

Core Technical Advantages

• Per-Point Individual Isolation: Features 16 completely independent isolated channel grids, permitting the simultaneous monitoring of distinct AC phases or separate field power sources on a single module without phase short-circuit risks.
• Programmable Logic Filter Times: Supports highly customizable input delay filters (selectable up to 18 ms) combined with rapid hardware response times to successfully suppress contact bounce and high-frequency line noise.
• Advanced Thermal Derating Matrix: Optimized to safely dissipate up to 5.8 Watts at 60 degrees Celsius, providing robust multi-channel configuration charts to handle continuous high-temperature field operations with maximum stability.

Technical Specifications

Installation & Engineering Guide

• Chassis Placement & Insertion: Ensure the primary system power supply is completely isolated before beginning installation. Align the 0.30 kg hardware frame within the selected slot guides of the 1756 ControlLogix chassis, pushing it backward firmly until the top and bottom retention clips snap completely over the structural chassis rail tabs.
• 36-Pin RTB Wiring Configurations: Terminate your 240V AC field inputs through an approved 1756-TBCH (extended clamp) or 1756-TBS6H (spring clamp) 36-pin removable terminal block. Because each channel is fully isolated, always run both the active signal line and its respective neutral return line directly to the designated channel terminal pair.
• Operating Environment Derating: Monitor your local enclosure temperature guidelines closely. When executing full system density, all 16 channels can remain ON up to 30 degrees Celsius at 265 VAC; however, if operating at 40 degrees Celsius, limit simultaneous active channels to 8 points max, or derate the operational input limit down to 242 VAC at 60 degrees Celsius with all channels active.

Technical FAQs

Q1: How is the total execution delay calculated for the 1756-IM16I AC input paths?
A1: The total turnaround delay from screw to backplane is a combination of native hardware circuit latency and user-selected filter times. Going from Off-to-On, it equals the 10 ms max hardware delay plus a selectable 1 or 2 ms filter. Going from On-to-Off, it is an 8 ms max hardware delay plus a selectable 9 or 18 ms filter block.

Q2: What is the main advantage of point-to-point isolation on this specific digital input card?
A2: Unlike standard grouped inputs that share a common return bus, per-point isolation provides a completely separate circuit for each of the 16 paths. This allows you to mix different AC voltage phases or feed signals from entirely separate safety substations into a single physical card without risk of catastrophic cross-phase failure.

Q3: Does the lightweight 0.30 kg construction of this module compromise its long-term reliability?
A3: No. At roughly 0.30 kg, its specialized compact frame is optimized to save chassis balance while providing rugged structural components that comply with high-voltage industrial insulation profiles, fully meeting standard ControlLogix ratings for mechanical shock and vibrations.