Allen-Bradley 1756 ControlLogix Modules 1756-OB16I

Technical Dossier

Product Details And Specifications

Allen-Bradley 1756 ControlLogix Series Technical Notes

The Allen-Bradley 1756 ControlLogix platform is one of the most widely deployed programmable automation controller (PAC) architectures in global heavy industry. Installed across petrochemical refineries, nuclear power generation facilities, offshore oil & gas platforms, pulp and paper mills, and large-scale water treatment infrastructure, the 1756 backplane-based system has served as the backbone of process and discrete control since its commercial introduction in the late 1990s. Its modular chassis architecture — supporting 4, 7, 10, and 17-slot configurations — allows engineers to construct highly scalable control nodes with deterministic I/O scanning, redundant controller support, and multi-network communication from a single rack. The 1756-OB16I is a 16-point isolated digital output module within this platform, rated for 10–30V DC operation with individual point isolation, making it the standard selection for applications requiring output channel independence and protection against ground loops in field wiring.

1756 ControlLogix Full Catalog & Functionalities (SKU List)

Digital Output Modules

• 1756-OB16I: 16-point isolated 10–30V DC output module, individual point isolation, 0.5A per point
• 1756-OB16D: 16-point diagnostic 10–30V DC output, fault detection per point, electronic fusing
• 1756-OB32: 32-point 10–30V DC sourcing output, high-density discrete control
• 1756-OB8: 8-point 10–30V DC sourcing output, standard density discrete output
• 1756-OA16: 16-point 74–265V AC triac output, zero-cross switching, industrial AC loads
• 1756-OA8D: 8-point diagnostic AC output, 74–132V AC, per-point fault reporting
• 1756-OW16I: 16-point isolated relay output, 10–265V AC/DC, dry contact switching

Digital Input Modules

• 1756-IB16I: 16-point isolated 10–30V DC input, individual point isolation, high-noise immunity
• 1756-IB32: 32-point 10–30V DC sinking input, high-density discrete sensing
• 1756-IA16I: 16-point isolated 74–132V AC input, isolated channel architecture
• 1756-IC16: 16-point 48V DC TTL-compatible input, low-voltage logic interfacing

Analog I/O Modules

• 1756-IF16: 16-channel analog input, 4–20mA / 0–10V, 16-bit resolution, single-ended
• 1756-OF8: 8-channel analog output, 4–20mA / ±10V, 16-bit resolution
• 1756-IF8: 8-channel differential analog input, 16-bit, high-accuracy process measurement
• 1756-IR6I: 6-channel isolated RTD/resistance input, Pt100/Pt1000/Ni120 compatible

Controller & Communication Modules

• 1756-L73: ControlLogix 5573 controller, 8MB user memory, standard process control
• 1756-L83E: ControlLogix 5583 controller, EtherNet/IP embedded port, 20MB memory
• 1756-EN2T: EtherNet/IP communication module, dual-port, 100Mbps, DLR capable
• 1756-CNB: ControlNet bridge module, coax/fiber media, scheduled messaging
• 1756-PA72: 120/240V AC power supply, 10A backplane current, standard chassis power
• 1756-PB72: 18–32V DC power supply, 10A backplane current, DC-powered installations

Quality Control for the 1756 ControlLogix Range

Each 1756-series module processed by DriveKNMS undergoes a structured verification protocol adapted to the module's functional category. Digital output modules including the 1756-OB16I are tested under load across all 16 output points, with isolation resistance measured between each point and chassis ground to confirm the isolated architecture is intact. Backplane connector pins are inspected under magnification for fretting corrosion — a common failure mode in modules removed from high-vibration environments. Analog modules are calibrated against NIST-traceable references with linearity and offset error recorded per channel. Communication modules are tested for EtherNet/IP or ControlNet connectivity using live network simulation, with CIP messaging latency logged. All modules are powered through a controlled 1756 chassis test fixture running current-generation Logix firmware to confirm module identity, revision reporting, and I/O tree recognition before dispatch.