Product Overview
The Allen-Bradley 1746-OB32 is a Digital DC Output Module from the SLC 500 series by Rockwell Automation. Designed for high-density, low-current DC applications, this module provides 32 discrete output channels at a nominal 24VDC. It is ideal for energizing pilot lamps, buzzers, horns, sirens, solenoids, and motors within the 5-50VDC operating range. The module fits any slot except slot 0 in a 1746 chassis, making it a versatile choice for expanding your SLC 500 system.
Technical Specifications Breakdown
Key parameters for the 1746-OB32 are listed below for quick reference:
| Feature | Specification |
|---|---|
| Manufacturer | Rockwell Automation |
| Brand | Allen-Bradley |
| Part Number | 1746-OB32 |
| Series | SLC 500 |
| Module Type | Digital DC Output Module |
| Number of Outputs | 32 |
| Voltage Range | 5-50 Volts DC |
| Current per Output | 0.5-0.25 amps |
| Current per Module | 8 amps |
| Points per Common | 16 |
| Backplane Current (5 Volts) | 190 milliamps |
| Nominal Output | 24VDC |
| Signal Delay, ON | 0.1 ms |
| Signal Delay, OFF | 1.0 ms |
Industry Applications
This digital output module excels in high-current applications where reliable switching of DC loads is critical. Common use cases include controlling solenoid valves in packaging lines, actuating motor starters in conveyor systems, and driving indicator lamps in control panels. With 32 outputs and 16 points per common, the 1746-OB32 reduces wiring complexity and panel space while delivering consistent performance in harsh industrial environments.
Installation & Setup Guidance
Install the 1746-OB32 in any available slot of a 1746 chassis except slot 0, which is reserved for the processor. Use a compatible Removable Terminal Block (RTB) such as the 1746-N3 or 1492 wiring system for proper termination and wire size. Ensure the module door can close fully after wiring to maintain protection. For AC-powered loads, implement an interposing relay with a 24VDC coil to isolate the module from electrical noise and voltage mismatches.
Maintenance & Reliability
Periodically inspect the module for dust accumulation and ensure the LED indicators for each channel are functioning. The module operates reliably in temperatures from 0 to 60°C with non-condensing humidity. Given its UL and C-UL listing for Class I, Division 2 hazardous locations, it is suitable for environments with potential gas or dust hazards. No special maintenance is required beyond routine visual checks.
Compatibility & Integration
The 1746-OB32 integrates seamlessly with SLC 500 fixed and modular hardware. It draws 190 mA from the 5V backplane, ensuring low power consumption. The module supports sourcing outputs and is compatible with 24VDC loads within the 5-50VDC range. For systems requiring isolation, the output circuit is tested at 1500V AC for one minute.
Selection Guide & Purchasing Advice
When selecting the 1746-OB32, verify your system's backplane current capacity and ensure the load current per output does not exceed 0.5 amps. For high-current applications, the module's 8A per module rating provides ample headroom. SpareTechPLC stocks this module and can advise on lifecycle status and availability. Contact our team for bulk pricing or expedited shipping.
Troubleshooting & Common Issues
If an output channel fails to energize, check the corresponding LED indicator. A lit LED with no load activation suggests a wiring issue or a faulty load device. If the LED is off, verify the backplane connection and module seating. For intermittent faults, inspect the RTB for loose wires or corrosion. The module's 0.1 ms ON delay and 1.0 ms OFF delay help diagnose timing-related issues in fast-switching applications.
