Product Overview

The Allen Bradley 1756-IH16I functions as a high-voltage discrete input module for the ControlLogix platform. This single-slot module provides 16 individually isolated input points that sense 125V DC status signals from field devices like limit switches, circuit breaker auxiliary contacts, and pushbutton stations. Because it offers true channel-to-channel isolation, engineers can wire disparate DC electrical circuits into a single chassis interface without risking cross-talk or ground loop interference. We supply this product as a 100% brand-new, factory-original unit to ensure optimal signaling precision and maximum network uptime.

Technical Specifications

Engineering Advantages

• Eliminates Ground Loop Interaction: Complete channel-to-channel (input-to-input) 250V continuous galvanic isolation allows a single module to safely monitor points tied to completely different, ungrounded battery systems or separate DC substations.

• Withstands Severe Electrical Transients: Routine factory testing up to 1350V AC for 2 seconds ensures the internal semiconductor components survive the high-voltage spikes and inductive kicks common in power utility and heavy industrial environments.

• Supports Flexible Wiring Topologies: The 125V DC sink/source design accommodates both positive-switching and negative-switching field configurations. This versatility simplifies retrofits in older legacy panels without requiring rewiring of the existing field instruments.

• Lowers Thermal Stress in Dense Panels: The ultra-low backplane draw (0.71W total power) limits the heat buildup inside sealed control cabinets. This cooling advantage keeps adjacent processor and communication modules well within safe operational limits.

FAQs

• Can I mix sink and source wiring configurations on the same 1756-IH16I module?

  Yes. Because this specific module features 16 individually isolated points, every input channel functions as a self-contained electrical circuit. You can wire Channel 0 in a sinking configuration and Channel 1 in a sourcing configuration without causing short circuits or backplane damage.

• Which Removable Terminal Blocks (RTBs) fit this high-voltage digital module?

  The 1756-IH16I requires the 36-pin extended depth terminal blocks to safely handle high-voltage spacing requirements. You must use either the 1756-TBCH (cage clamp style) or the 1756-TBS6H (spring clamp style) terminal housings. Note that standard 20-pin RTBs will not fit this card slot.

• How does the input delay filter setting affect industrial performance?

  The card applies a base hardware delay of 6 milliseconds to filter out fast high-voltage transient noise. You can configure additional digital filter times via Studio 5000 software to reject mechanical switch bounce, ensuring the PLC registers only legitimate signal transitions.