Allen‑Bradley 1746‑OB32 SLC 500 32‑Channel Digital Output Module

1746‑OB32 is a high-density digital output module for Rockwell Allen‑Bradley SLC 500 PLC racks. It features 32 sourcing DC output channels to drive 10–30VDC field loads including solenoid valves, indicator lamps, small contactors and solid-state relays. It receives logic commands from the SLC CPU via the rack backplane and converts internal control signals into external driving power for on-site actuators.

This single-slot compact module adopts opto-electrical isolation between backplane and field circuits to block industrial EMI interference. Every channel has a dedicated LED indicator for real-time status monitoring. It supports hot-swap maintenance, uses removable terminal blocks for convenient wiring, and provides reliable high-density output expansion for packaging, material handling and power auxiliary automation systems.

Main Specifications

• Brand: Allen‑Bradley (Rockwell Automation); Model: 1746‑OB32; Series: SLC 500 1746 I/O System
• Channel Layout: 32 sourcing DC output points, grouped into four isolated common banks
• Load Voltage Range: 10 VDC to 30 VDC, rated operating voltage 24 VDC
• Output Current Rating: 0.1 A per single channel, maximum 1.6 A per common bank, total 3.2 A full module
• Switching Response Time: Max 10 μs turn-on delay, max 400 μs turn-off delay
• Isolation Rating: 500 VDC optical isolation separating field loads and PLC internal bus
• Backplane Power Consumption: 0.1 A @ 5 VDC, no external backplane 24 VDC draw
• Mounting Structure: Single slot for standard 1746 rack, detachable screw terminal block, IP20 cabinet protection
• Operating Environment: -20℃ ~ +60℃ continuous working temperature, 5%–95% RH non-condensing, shock and vibration resistant
• Diagnostic Function: Independent LED status light for each channel to display output active/inactive state
• Certifications: CE, UL listed, fully compliant with international factory automation standards

Core Functions

• Execute digital control logic signals transmitted from SLC 5/01 to 5/05 CPUs and output sourcing DC power to field actuators.
• Optical isolation protects PLC core circuits from surge voltage, inductive kickback and electrical noise generated by solenoids and contactors.
• Front panel LED indicators allow maintenance staff to quickly verify channel working status without programming software connection.
• Four-group independent common terminals support flexible partition of different load voltage circuits to avoid cross-loop interference.
• Built-in transient suppression circuits absorb inductive load reverse voltage to extend service life of internal output chips.
• Hot-swappable modular design enables single module replacement without full PLC rack shutdown to cut production maintenance downtime.

Application Scenarios

• High-density output spare replacement for SLC 500 PLC cabinets in automated packaging lines, conveyor systems and automotive assembly workshops.
• Actuator driving module for water treatment pumping stations, heating furnace valve control and textile machinery automation equipment.
• Backup spare inventory for petrochemical auxiliary interlock control, mining equipment safety indication and new energy power distribution automation cabinets.
• Matching expansion output module paired with SLC CPU, 1746‑IB16 digital input modules and analog signal acquisition boards.
• Retrofit replacement for aging automation systems with channel burnout, output failure and unstable load driving performance.

• Global aftermarket spare stock for automation maintenance teams supporting Rockwell SLC 500 control equipment worldwide.