Purchase now: Allen-Bradley 1756-IA16I Isolated Input Module
Purchase now: Atlantechdrives provides you the 1756-IA16I, a premium, industrial-grade 16-point 120V AC digital input module engineered by Rockwell Automation for the ControlLogix 1756 programmable automation controller (PAC) platform. While standard AC input modules group their channels together sharing a single common wire, the highly critical «I» designation in this part number stands for Individually Isolated. This means every single one of the 16 input channels possesses its own dedicated internal galvanic isolation and its own separate return (common) terminal. This sophisticated architecture allows the module to safely accept 120VAC input signals sourced from completely different electrical phases (L1, L2, L3), disparate transformers, or physically separate machine panels without any risk of creating catastrophic electrical ground loops or phase-to-phase short circuits. It is the ultimate, uncompromising solution for monitoring diverse high-voltage field devices—such as heavy motor starter auxiliary contacts, isolated relay panels, and plant-wide limit switches—across massive chemical processing plants, automotive assembly lines, and continuous power generation facilities.
Technical Specifications of the 1756-IA16I
The 1756-IA16I provides an incredibly robust barrier between the harsh, high-voltage factory floor and the sensitive 5V DC silicon logic of the ControlLogix backplane, ensuring maximum CPU protection against electrical surges.
- Part Number: 1756-IA16I
- Platform: ControlLogix 1756 System
- Input Type: Digital AC Input (Individually Isolated)
- Number of Inputs: 16 Points (16 separate commons)
- Operating Voltage Range: 79…132V AC, 47…63 Hz
- Maximum Input Current: 15 mA at 132V AC per channel
- Required Terminal Block (RTB): 1756-TBCH (36-pin cage clamp) or 1756-TBS6H (36-pin spring clamp)
- Backplane Current Draw: 125 mA at 5.1V DC; 3 mA at 24V DC
Expert Tips: The IA16 vs. IA16I Engineering Dilemma
Specifying the correct module is vital for plant safety and panel design. Expert Tip: Many junior engineers mistakenly order the standard 1756-IA16 instead of the isolated 1756-IA16I to save a small amount of budget. However, if your factory field devices are powered by different circuit breakers or entirely different control transformers, wiring them into a standard grouped module will instantly bridge those circuits together. If one phase is L1 and the adjacent wire is L2, plugging them into a shared-common module will result in a violent 240V AC dead short, instantly destroying the module and potentially starting a panel fire. The 1756-IA16I provides 16 electrically independent circuits, giving control engineers absolute freedom to route any 120V AC signal into the rack with total peace of mind.
Installation Advice: Wiring the 36-Pin RTB
Because every channel is individually isolated, the 1756-IA16I requires two physical wires for every single input (the hot signal and its dedicated neutral/return). This means a fully utilized module will have 32 physical copper wires landing on the 36-pin Removable Terminal Block (RTB). You must exercise extreme care during the panel build. Using thick 14 AWG wire for all 32 connections will massively overcrowd the RTB, making it nearly impossible to snap the plastic cover shut and creating dangerous strain on the terminal clamps. It is highly recommended to use 16 AWG or 18 AWG MTW wire, properly finished with insulated wire ferrules, to ensure a clean, reliable, and safe installation.
Frequently Asked Questions (FAQs)
Q: Can the 1756-IA16I module be hot-swapped while the machine is actively running?
A: Yes. Like all ControlLogix I/O modules, it fully supports RIUP (Removal and Insertion Under Power). However, you must first physically unsnap and remove the wired RTB from the front of the module to disconnect the live 120VAC field power before pulling the module out of the chassis backplane.
Q: Does this module support input filtering?
A: Absolutely. To prevent mechanical switch bounce from triggering false inputs, you can configure the software input filter times (from 1ms up to several milliseconds) within Studio 5000 Logix Designer for each individual channel.
Do you need more references from this brand? Explore our full catalog of Allen-Bradley here.
For 120V AC automation cycles, this discrete input module is typically paired with a matching 1756-OA16 output card.
For 120V AC discrete sensing, this 16-point input card requires stable power provided by the 1756-PA75 system supply.
This isolated AC input module is technically designed to be housed in a robust 1756-A10 10-slot chassis for safe industrial control.
