Product Overview
The Allen-Bradley 1746-OA8 is a discrete AC output module from the SLC 500 series, manufactured by Rockwell Automation. Designed for general-purpose applications, this module provides eight (8) output channels arranged in two (2) groups of four (4) channels each. It delivers an output voltage range of 85-264VAC with a frequency of 47-63 Hz. The backplane current consumption is 185 mA at 5VDC. For maintenance engineers, this module offers straightforward integration and reliable switching for AC loads.
Technical Specifications Breakdown
Key parameters for the 1746-OA8 are listed below for quick reference:
| Feature | Specification |
|---|---|
| Module Type | Discrete AC output module |
| Number of Outputs | 8 |
| Number of Groups | 2 |
| Channels per Group | 4 |
| Output Voltage Range | 85-264 VAC |
| Nominal Output Voltage | 120 / 240 VAC |
| Backplane Current Consumption | 185 mA |
| Continuous Current per Point at 30 °C | 1.00 A |
| Continuous Current per Point at 60 °C | 0.5 A |
| Continuous Current per Module at 30 °C | 8.0 A |
| Continuous Current per Module at 60 °C | 4.0 A |
| On-State Voltage Drop, Max | 1.5V at 1.0 A |
| Surge Current per Point | 10 A for 25 ms |
| ON Signal Delay, Max Resistive Load | 1 ms |
| OFF Signal Delay, Max Resistive Load | 11 ms |
Industry Applications
This discrete AC output module is ideal for general-purpose industrial control tasks such as switching solenoid valves, motor contactors, and indicator lights in manufacturing lines. For example, in a packaging facility, the 1746-OA8 can reliably control AC-powered actuators. From a maintenance perspective, its robust surge current rating of 10 A per point for 25 ms helps prevent nuisance failures during inrush events, reducing downtime.
Installation & Setup Guidance
When installing the module, ensure the SLC 500 chassis is powered off. Insert the 1746-OA8 into any available slot, securing it firmly. Verify that the output voltage range (85-264VAC) matches your load requirements. Use appropriate fusing for each group to protect against overcurrent. The backplane current consumption of 185 mA at 5VDC should be accounted for in your system power budget. Always follow standard lockout/tagout procedures.
Maintenance & Reliability
For reliable operation, inspect the module periodically for signs of overheating or loose connections. The continuous current per point derates from 1.00 A at 30 °C to 0.5 A at 60 °C, so ensure adequate ventilation in high-temperature environments. The module's on-state voltage drop is minimal at 1.5V, contributing to efficient power delivery. No special maintenance beyond routine visual checks is required.
Compatibility & Integration
The 1746-OA8 integrates seamlessly with the Allen-Bradley SLC 500 programmable controllers. It communicates via the backplane, requiring no additional protocols. The module is compatible with standard 85-265VAC AC supplies (47-63 Hz). For replacement or expansion, verify compatibility with your existing SLC 500 chassis and power supply.
Selection Guide & Purchasing Advice
When selecting the 1746-OA8 for your application, consider the load current per point and ambient temperature. For high-temperature environments (up to 60 °C), derate to 0.5 A per point. SpareTechPLC offers this module with fast shipping and expert support. Please verify current lifecycle status and availability with SpareTechPLC before ordering.
Troubleshooting & Common Issues
If an output fails to energize, first check the load wiring and supply voltage (85-264VAC). Use a multimeter to verify the module's backplane power (5VDC at 185 mA). If the module does not respond, inspect the group fuses. For intermittent operation, ensure the ambient temperature is within limits and that the continuous current per point does not exceed 1.00 A at 30 °C or 0.5 A at 60 °C. The OFF signal delay of 11 ms may affect fast-switching applications.
