1756-IM16I Allen-Bradley ControlLogix 240V AC 16-Pt Isolated Input Module

Allen-Bradley 1756-IM16I ControlLogix Isolated Input Module Overview

The 1756-IM16I is a specialized high-voltage AC digital input module designed for the ControlLogix platform. Engineered for robust industrial interface tasks, this module provides 16 individually isolated inputs. This "per-point" isolation ensures that electrical noise or faults on one channel do not propagate to others, offering superior signal integrity. The 1756-IM16I operates within a 159-265V AC range, making it ideal for heavy-duty power monitoring and control logic. 

Technical Specifications

• Manufacturer: Rockwell Automation / Allen-Bradley
• Model: 1756-IM16I
• Series: ControlLogix
• Module Type: Isolated Digital Input Module
• Inputs: 16 Individually Isolated Inputs
• Voltage Category: 240V AC (50/60 Hz)
• Operating Voltage Range: 159V to 265V AC
• Backplane Current: 100mA @ 5.1V / 3mA @ 24V
• Power Dissipation: 5.8 Watts @ 60°C
• Thermal Dissipation: 19.78 BTU/hour
• Off-State Max Voltage: 40V AC
• Input Delay Time: Programmable (Hardware 10ms + User Filter)
• Compatible RTB: 1756-TBCH or 1756-TBS6H (36-Pin)

Global PLC Spare HUB's Insight

The 1756-IM16I is a "problem-solver" module for complex electrical environments. While standard AC modules share a common return, the 1756-IM16I features independent circuitry for every channel. This is crucial when signals originate from different power sources or phases where a common neutral is unavailable or unsafe. In our experience, utilizing the programmable filter times (9ms or 18ms) effectively eliminates "contact bounce" from large mechanical limit switches, ensuring stable logic execution in high-vibration settings.

Application & Diagnostics

• Hardware Diagnostics: Monitors field-side power and reports Change of State (COS) data to controller tags.
• Device Compatibility: Interfaces perfectly with 240V limit switches and motor starter auxiliary contacts.
• Target Scenarios: Ideal for legacy plant upgrades, power distribution centers, and long-distance cable runs.
• System Integration: Requires a 36-pin RTB; ensure it is fully seated to prevent backplane communication errors.

Shipping & Warranty

• Dispatch Time: Fast processing for all 1756-IM16I orders within 24-48 hours.
• Global Express: Door-to-door delivery via FedEx, UPS, and DHL.
• Warranty Terms: This product includes a full 12-month technical warranty.
• Package Content: One 1756-IM16I Module in professional industrial anti-static packaging.

Frequently Asked Questions (FAQ)

• What does "Individually Isolated" mean for the 1756-IM16I?

Unlike standard modules sharing one neutral, each point has its own two-terminal return, allowing different voltage phases on one module.

• How do the temperature-based voltage ratings affect my installation?

At 60°C, the maximum voltage drops to 242V AC. If your environment is hot, ensure supply voltage does not exceed this derated limit.

• Can I mix different AC voltages on the 1756-IM16I?

Yes, provided all fall within 159-265V AC. Because each channel is isolated, they do not need to share a common phase.

• Why is my input status flickering in the PLC software?

This is often caused by electrical noise. Adjust the user-selectable input filter time to 18ms to "smooth" the signal logic.

• What is the best way to choose between the 1756-IA16 and the 1756-IM16I?

Choose the 1756-IM16I if working with 240V AC and needing to prevent ground loops between different power circuits.

Selection & Purchasing Guide

• Confirm your field voltage is 240V AC; for 120V AC applications, the 1756-IA16 is the correct alternative.
• Always order a 36-pin 1756-TBCH or 1756-TBS6H separately, as they are not included.
• Account for the 5.8W power dissipation when calculating your chassis power supply and enclosure cooling.

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