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Phone: +86 16626708626Description
Key Technical Specifications
- Catalog Number: 1746-OB16E
- Manufacturer: Allen-Bradley
- Product Family: SLC 500
- Module Type: Electronically protected DC output module
- Output Count: 16
- Output Type: Sourcing
- Output Voltage Range: 10-30 VDC
- Backplane Current at 5 VDC: 135 mA
- Continuous Current per Point: 1 A at 30 °C
- Continuous Current per Point: 0.5 A at 60 °C
- Signal Delay: 1 ms ON, 1 ms OFF
- Protection: Electronic current fold-back on overload/short circuit
Product Introduction
The Allen-Bradley 1746-OB16E is a 16-point sourced DC output module for the SLC 500 platform. It drives 24 VDC loads and includes electronic protection that limits current during overload or short-circuit conditions.
This module is used where a legacy SLC 500 panel needs 16 protected outputs with fast fault reaction. The 1746-OB16E is a better fit than a plain output card when the field loads are prone to shorts, but the wiring still has to match the sourcing output style.
1746-OB16E
1746-OB16E
Troubleshooting Quick Reference
| Symptom | Possible Cause | Relevance to this Part | Quick Check Method | Recommendation |
|---|---|---|---|---|
| Output turns off under load | Channel overload or short circuit | ✅ High | Measure load current and inspect the field wiring | Clear the short or reduce the load before replacing the module |
| Output cycles on and off | Electronic protection is tripping | ✅ High | Watch the output state while disconnecting the load | Check for a shorted coil or wiring fault |
| LED on, load not energized | Open load, blown field fuse, or wrong wiring | ✅ High | Measure 10-30 VDC at the load and verify the commons | Check the external circuit first |
| One channel dead, others work | Damaged channel or field wiring issue | ✅ High | Move the field wire to another known-good channel | If the fault follows the channel, the module is suspect |
| All outputs dead | Missing supply or rack power issue | ✅ High | Measure the output supply and backplane power | Verify chassis power before assuming card failure |
| Load works on one channel but not another | Miswired output common or terminal issue | ✅ High | Compare the wiring against the module terminal diagram | Correct the common wiring and retest |
If you are stuck, send photos of the wiring, fault LED, and load diagram to technical support.
Frequently Asked Questions
Q: What does the 1746-OB16E do?
It is a 16-point 24 VDC sourcing output module for the SLC 500 family with electronic overload protection.
Q: Is this a relay output module?
No. It is a solid-state DC output card, not a dry-contact relay module.
Q: What makes the “E” version different?
The “E” version includes electronic protection and current fold-back. That helps when field wiring has short-circuit risk.
Q: Is it still made by Rockwell?
No. It is discontinued, so most units on the market are surplus or refurbished.
Q: Can I use it with 120 VAC loads?
No. This is a DC output module. AC loads need an AC-rated output module or a relay output stage.
Q: Why does the output shut off under overload?
That is the protection doing its job. The module limits current instead of burning up the output channel.
Q: What should I verify before ordering?
Check the exact part number, the 24 VDC sourcing output style, the load current, and the wiring common. The biggest mistake is treating it like a plain 1746-OB16 when the protected behavior is actually required.
