Allen-Bradley 1746-OB32 SLC 500 Digital DC Output Module

The Allen-Bradley 1746-OB32, also cataloged as the 1746-OB32 SLC 500 digital DC output module, serves as the primary SLC 500 32-point DC sourcing output module utilized to execute high-density discrete load switching across SLC 500 backplane-controlled rack systems. Configured for 24 VDC transistor-based output control in SLC 500 architectures, the Allen-Bradley 1746-OB32 provides direct electrical switching of 32 field channels via two isolated output groups managed through 5 VDC backplane logic.

Suffix Breakdown & Model Matrix

No suffix segmentation is defined in the provided documentation. The 1746-OB32 is treated as a fixed configuration module within the SLC 500 digital output family.

Hardware Specifications

SLC 500 Backplane Bus and High-Density Output Scaling Behavior

The 1746-OB32 interfaces with the SLC 500 backplane via 5 VDC logic-level communication, drawing 190 mA for internal opto-isolation and transistor gate drive structures. Output architecture is partitioned into two 16-point commons, enabling structured current return paths and segmented field wiring distribution.

Channel activation is synchronized with PLC scan cycles, where ON/OFF transitions are executed through semiconductor switching elements with deterministic latency defined by internal propagation and load-dependent response. High-density output scaling is constrained by thermal dissipation across the module body and cumulative channel loading under continuous operation.

The transistor-based sourcing topology eliminates mechanical wear mechanisms while introducing defined leakage and voltage drop characteristics during OFF-state and conduction phases.

Frequently Asked Questions (FAQ)

Q: Can the 1746-OB32 be hot-swapped while the SLC 500 rack is energized?
A: Hot-swapping is not specified. Module insertion or removal should be performed with system power removed to avoid backplane disturbance.

Q: How is backplane current distributed across the module?
A: The module draws a fixed 190 mA @ 5 VDC from the backplane regardless of output switching activity.

Q: What limits simultaneous channel loading on the 32 outputs?
A: Limitation is defined by per-point current rating, total module current capacity, and thermal dissipation constraints across both output groups.

Field Installation Guidelines

Install the module into a compatible SLC 500 rack slot ensuring full backplane connector engagement. Output wiring must be terminated into the two 16-point common groups with correct segregation to maintain return path integrity.

Maintain separation between DC output wiring and high-voltage conductors to reduce electromagnetic coupling across densely packed channels. Use appropriate conductor sizing to match per-channel current limits under continuous operation.

Verify load compatibility within the 5 to 50 VDC operating range prior to energization. Inductive loads require external suppression components to mitigate switching transients during transistor turn-off events.