Product Overview

The Allen-Bradley 1746-OBP16 is a 16-channel, DC sourcing output module designed for the SLC 500 programmable controller system from Rockwell Automation. This module serves as a critical interface between the digital logic of the SLC 500 processor and the physical actuators in an industrial environment. Its primary function is to convert low-power logic signals from the controller’s backplane into isolated switching signals capable of controlling external DC loads. The Allen-Bradley 1746-OBP16​ operates on the “sourcing” principle, meaning that when a channel is activated (turned ON by the PLC logic), it internally connects the load to the common positive voltage source (+VDC), allowing current to flow from the module’s terminal, through the load, to ground. This positive logic, 12-24 VDC module is engineered to reliably drive a wide array of field devices, providing the essential link that transforms control program decisions into physical actions on the factory floor.As a member of the extensive 1746 I/O module family, the 1746-OBP16​ is a fundamental building block for expanding the output capacity of any SLC 500 system, whether housed in a 4-slot, 7-slot, 10-slot, or 13-slot chassis. Its “OBP” designation breaks down as: “O” for Output, “B” for the specific electrical design series, and “P” for Positive Logic (sourcing). The module is valued for its high density (16 points in a single slot), straightforward integration, and proven reliability. In a typical control panel, the Allen-Bradley 1746-OBP16​ would be used to energize indicator lamps, small relays, solenoid valves, and other DC-powered devices that require a robust and electrically isolated switching signal. By providing individually fused outputs and optical isolation, the module protects the sensitive SLC 500 backplane from potential field-side faults like short circuits or overcurrent conditions. The 1746-OBP16​ represents a classic, workhorse output solution that has been instrumental in countless automation applications, known for its durability and ease of use in demanding industrial settings.

Technical Specifications

Main Features and Advantages

The Allen-Bradley 1746-OBP16​ output module delivers a robust set of features centered on protection, diagnostics, and ease of use. A primary advantage is its individual electronic fuse protection for each of the 16 output channels. This sophisticated design isolates a fault to the specific channel where it occurs—such as a shorted solenoid coil—preventing the fault from affecting neighboring channels or causing the module’s entire power supply to shut down. When a fuse operates, the channel’s LED indicator will flash, providing immediate visual diagnostics that guide the technician directly to the problematic circuit, dramatically reducing mean-time-to-repair (MTTR).Reliable Sourcing Design and Clear Diagnostics: The module’s sourcing (positive logic) output design is intuitive for many control panel layouts, where a common positive 24VDC rail is distributed. The 1746-OBP16​ provides excellent electrical isolation (500V rms) between the field wiring and the controller’s sensitive backplane, protecting the PLC from voltage transients and noise. Each channel’s bright red LED gives unambiguous confirmation of the output’s commanded state from the PLC program. The module is designed for high inrush capability, allowing it to reliably energize loads like solenoid valves and small relay coils that have high initial turn-on currents. Furthermore, the Allen-Bradley 1746-OBP16​ is engineered for the rigors of the industrial environment, with a wide operating temperature range and robust construction. Its use of a removable terminal block simplifies wiring and maintenance, as the entire block can be pre-wired on a bench before being snapped onto the module. This combination of high-density point count, individual channel protection, and clear diagnostics makes the 1746-OBP16​ a dependable and cost-effective choice for a vast array of standard DC output applications in SLC 500 systems.