Allen-Bradley 1746-OW16/C SLC 500 Relay Output Module

The Allen-Bradley 1746-OW16/C, also cataloged as the 1746-OW16/C relay output module, serves as a 16-point electromechanical switching interface for AC/DC load control within SLC 500 chassis-based I/O architectures. The Allen-Bradley 1746-OW16/C (1746-OW16/C relay output module) provides discrete contact actuation through backplane-synchronized control of mechanical relay outputs across SLC 500 systems.

The module executes controller-driven output state transitions via internal relay coils, providing galvanically isolated hard-contact switching between field loads and controller logic. Output grouping is implemented as 8 points per common, enabling segmented load distribution across dual relay banks.

Hardware Specifications

SLC 500 Backplane Control and Relay Contact Switching Behavior

The 1746-OW16/C implements backplane-driven relay coil excitation, where output image data from the SLC 500 processor is translated into mechanical contact actuation. Each relay channel provides hard galvanic separation between field wiring and controller logic domain through electromechanical switching.

Channel grouping into 8-point commons defines current return segmentation, limiting shared load distribution across relay banks. Switching latency is determined by mechanical actuation time of the relay elements, independent of backplane scan timing once coil energization is issued.

The optical isolation stage decouples internal logic from field-side switching transients, reducing susceptibility to external voltage disturbances during contact transitions.

Frequently Asked Questions (FAQ)

Q: Can the 1746-OW16/C be hot-swapped in an energized SLC 500 rack?
A: No. Chassis power must be removed prior to module insertion or removal to avoid backplane disruption and relay state uncertainty.

Q: What determines switching speed in this module?
A: Switching speed is governed by mechanical relay actuation time rather than electronic propagation delay, resulting in slower response than solid-state modules.

Q: Are AC and DC loads supported simultaneously?
A: Yes. Each relay output supports AC or DC loads within its rated current limits, subject to contact wear and arc suppression conditions.

Field Installation Guidelines

Install the 1746-OW16/C into a compatible SLC 500 chassis slot ensuring full engagement with the backplane connector. Power isolation is required prior to installation or removal.

Field wiring must be connected according to 8-point common grouping, ensuring correct load return paths per relay bank. Inductive loads such as solenoids or contactors require external suppression elements (flyback diode or RC snubber) to limit contact arcing.

Maintain separation between relay output wiring and low-level signal conductors to reduce electromagnetic coupling. Verify chassis grounding continuity before system energization.