The Allen-Bradley 1746-OV32, also cataloged as the 1746-OV32 Current Sinking DC Output Module, operates as a dedicated hardware component for 32-point discrete signal execution within Allen-Bradley SLC 500 PLC chassis architectures. The module sinks output load current from connected 5...50 VDC field circuits to local common return paths upon instruction from the central processor. Operating with a 24 VDC nominal line voltage, each channel controls current sinking loads up to 0.5 A (at 30 deg C) or 0.25 A (at 60 deg C) to execute discrete switching operations across high-density I/O chassis racks.

Hardware Series & Matrix Breakdown

• 1746: SLC 500 system chassis expansion module base platform.

• OV: High-density current sinking transistor output electronic hardware designator.

• 32: 32 operational output channels divided into two isolated 16-point common groups.

• Series Revision C/D: Internal component updates for trace routing and semiconductor current switching profiles.

Hardware Operating Specifications

Deterministic Messaging & I/O Expansion

The module interfaces directly with the SLC 500 backplane bus to perform high-speed data exchanges without requiring backplane bus communication velocity licenses. Onboard processing logic distributes output data words directly to the output drivers, maintaining compatibility across ControlLogix/SLC bridges over EtherNet/IP deterministic networks. High channel integration optimizes system I/O density scaling while maintain firmware flash compatibility across backplane scanner interfaces and local processor rack structures.

Standard Order Fulfillment List

• 1 x Allen-Bradley 1746-OV32 Current Sinking Output Module

• 1 x Removable 40-Pin Wiring Connector Block

• 1 x Product Installation and Wiring Leaflet

Wiring Guidelines & Chassis Assembly

• Rack Installation Standoffs

  • De-energize the SLC 500 chassis backplane before inserting or extracting the module from the chassis slot.

  • Align the circuit board with the plastic chassis guides and push firmly until the top and bottom retaining latches click into place.

• Field Terminal Wiring Rules

  • Connect the positive terminal (+VDC) of the external load power supply to the load, with the load output returning to the module sink terminals.

  • Bundle low-voltage DC output wiring away from high-voltage AC conductors to reduce induced electromagnetic noise.

Frequently Asked Questions

• Does the 1746-OV32 module support hot-swapping while the SLC 500 rack is powered?

  No, the SLC 500 backplane does not support RIUP (Removal and Insertion Under Power); rack power must be turned off prior to removal.

• What current sinking load limits apply per channel at maximum operating temperatures?

  Each channel sinks up to 0.5 A at 30 deg C, which derates linearly to 0.25 A per output point at 60 deg C.

• What is the backplane current draw for the 1746-OV32 module?

  The module draws 0.27 A at 5 VDC from the local SLC 500 backplane logic power supply rail.

• How are the 32 output channels grouped electrically within the module?

  The 32 channels are split into two separate 16-point isolated groups, each with its own power supply common connection.

• What happens if an external load short-circuits on an output terminal?

  External fuses or current-limiting devices should be installed per group to protect internal transistor circuits from overcurrent damage.

• Does the 1746-OV32 require an external DC power source to operate the outputs?

  Yes, an external 5...50 VDC field power supply is required to drive the connected sinking output load circuits.

• Are the output status indicators powered from the backplane or the field power?

  The LED status indicators display channel switching logic state and draw power directly from the 5 VDC backplane supply.

• Can the module output points be wired in parallel to increase current capacity?

  Parallel wiring of sinking output channels is not recommended because slight switching delays can cause unequal load sharing.