Allen-Bradley 1746-OB32E SLC 500 32-Point 24V DC Electronically Fused Output Module

Description

Key Technical Specifications

Product Introduction & Supply Chain Strategy

The Allen-Bradley 1746-OB32E is a high-density 32-point 24V DC sourcing transistor output module designed for the SLC 500 automation system. It features built-in electronic short-circuit protection (“E-fusing”) that automatically trips output channels during field overcurrent events, protecting internal traces, solenoids, contactors, and field wiring without requiring manual physical fuse replacement.

With Rockwell Automation having officially discontinued the SLC 500 product line, holding New Surplus 1746-OB32E units in reserve prevents catastrophic downtime on dense control panels. Sourcing genuine New Surplus delivers factory-fresh electronic trip circuitry and zero semiconductor aging, eliminating output latchup risks and channel degradation inherent in second-hand pull-outs.

Installation & Configuration Guide

Stage 1: Pre-Installation (Prep & Safety)

1. Execute Lock-Out/Tag-Out (LOTO) on the 1746 chassis power supply and external 24V DC load power supplies.
2. Put on a properly grounded ESD wrist strap before handling the replacement card.
3. Label and photograph high-density terminal connector wiring (40-pin connector or dual 20-pin wiring arms) to ensure precise signal re-mapping.

Stage 2: Removal

1. Unfasten retaining screws or latches on the front field wiring connector and detach it straight off the module face.
2. Depress the upper and lower module release latches on the SLC 500 chassis frame simultaneously.
3. Slide the card straight out of the slot along its chassis guide rails to avoid bending backplane edge connector pins.

Stage 3: Installation (Clone & Seat)

1. Confirm the target slot address in the 1746 chassis matches the RSLogix 500 output table project configuration.
2. Align the circuit board edges with the top and bottom guide tracks of the chassis slot.
3. Push the module firmly into the slot until both upper and lower release latches snap into place securely.
4. Align the pre-wired terminal connector onto the front module header and tighten retaining screws securely.

Stage 4: Power-On & Testing

1. Apply 24V DC field supply power and verify voltage presence across terminal power pins.
2. Apply power to the 1746 rack power supply and observe the front status LEDs:
   • Output Status LEDs (0–31): Verify corresponding LED illumination when output bits are commanded ON in ladder logic.
   • Fuse Blow / Diagnostic LED: Verify the electronic fuse indicator is off. A lit diagnostic indicator signifies a field short circuit or thermal overload condition on that channel group.
3. Access RSLogix 500 online mode, navigate to Output Data Table registers (O:e.0 and O:e.1), and verify output bit operations.

1746-OB32E

1746-OB32E

Firmware/Software Versions & Upgrade Notes

• I/O Slot Configuration: The 1746-OB32E occupies 2 full 16-bit output words in the SLC 500 CPU data table (O:e.0 and O:e.1, where e is the slot number). In RSLogix 500, select catalog number 1746-OB32E 32-Out (10/30VDC) Electronically Fused.
• Electronic Fuse Reset: Once a short circuit fault is cleared in the field, electronic fuse channels can be reset via ladder logic or by cycling 24V DC field supply power to the module group.
• Firmware Notes: High-density discrete output cards utilize hardware-level logic for electronic fusing and require no field flash firmware updates. Hardware replacement is plug-and-play.

Frequently Asked Questions (FAQ)

Q: Is this 1746-OB32E module a Brand New Surplus unit or a refurbished part?

A: This product is a Brand New Surplus unit. It is not used, not pulled from a decommissioned plant, and not refurbished. All modules undergo rigorous quality verification to ensure OEM-level reliability.

Q: What is the benefit of the “E” suffix (1746-OB32E) compared to the standard 1746-OB32?

A: The “E” designation signifies Electronic Fusing. The 1746- includes active short-circuit protection that shuts down individual output channels during overload conditions without blowing physical fuses or damaging output transistors, whereas the standard 1746-OB32 lacks this active electronic circuit protection.

Q: Why avoid buying a lower-cost refurbished 1746- card?

A: High-density 32-point modules generate localized heat inside control enclosures. Refurbished units frequently suffer from thermal fatigue, micro-cracks in multi-layer circuit boards, or degraded electronic sensing components that fail to trip during short circuits, putting downstream field wiring at risk. Purchasing New Surplus guarantees 10 to 15 years of expected service life and total system peace of mind.

Q: How do you verify the quality and condition of legacy 1746- stock?

A: Every unit passes our inbound SOP quality checks: inspecting original OEM factory packaging, checking backplane edge connectors for zero insertion wear, verifying terminal header pins, and executing live 24V DC load switching and short-circuit protection tests on an SLC 500 test rack.

Q: Is it safe to hot-swap the 1746- card while the PLC system is powered up?

A: No. Allen-Bradley SLC 500 chassis backplanes do not support Hot-Swapping (RIUP). Pulling or inserting any 1746 module while backplane power is active causes arcing that can destroy the card, adjacent I/O cards, or the central CPU. Always disconnect chassis power first.

Q: What warranty coverage comes with this New Surplus 1746-?

A: All 1746- New Surplus modules carry our comprehensive 1-year replacement warranty. If any output channel, electronic fuse circuit, or internal component fails under standard operating parameters, we will immediately provide a replacement card or full refund.