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Phone: +86 16626708626Description
3. Key Technical Specifications
- Relay Type: Single-pole, double-throw (SPDT), epoxy-sealed
- Power Consumption: 5.8 Watts typical
- Contact Ratings (Standard): 2 A @ 30 Vdc, 250 Vac resistive
- Minimum Switched Current: 100 mA @ 12 Vdc
- Contact Life: 100,000 cycles @ 5 A, 24 Vdc
- Alarm Drive Logic: AND/OR voting from any monitor channels
- Front Panel LEDs: OK, TX/RX, CH ALARM per channel
- Operating Temperature: -30°C to +65°C
- Storage Temperature: -40°C to +85°C
- Humidity: 95% non-condensing
- Dimensions (I/O Module): 241 mm x 24.4 mm x 99.1 mm
- Weight (I/O Module): 0.4 kg (1.0 lb)
4. Product Introduction
The Bently Nevada 125720-01 is the spare 4-Channel Relay I/O Module for the 3500/32 series. It provides four independently programmable SPDT relay outputs with Alarm Drive Logic that uses AND/OR combinations from alerts, dangers, Not OK, or PPLs across the rack.
It installs in the rear slot paired with the 3500/32 main module. Use it for custom trip, shutdown, or annunciation logic in machinery protection applications. Each relay operates in normally energized or de-energized mode per application needs.
- 125720-01
- 125720-01
5. Troubleshooting Quick Reference
| Symptom | Possible Cause | Relevance to this Part | Quick Check Method | Recommendation |
|---|---|---|---|---|
| No OK LED | Power or main module issue | ❌ Low | Verify main 3500/32 module status | Check rack power and main module |
| Relay not activating | Logic configuration error | ✅ High | Review Alarm Drive Logic in software | Reload and test voting logic |
| CH ALARM LED stuck | Latching alarm or wiring | ✅ Medium | Check software status and contacts | Reset latched alarms |
| Intermittent relay operation | Contact wear or high load | ✅ Medium | Measure contact resistance | Reduce load or replace module |
| No response to alarms | Incorrect AND/OR voting | ✅ High | Simulate inputs in config software | Verify logic against requirements |
| High contact resistance | Arc damage from inductive loads | ✅ Medium | Test under load with multimeter | Add proper suppression if needed |
Contact support with configuration screenshots and relay test results if unresolved.
6. Frequently Asked Questions (FAQ)
What is the 125720-01 used for? It serves as the I/O portion for the 3500/32 4-Channel Relay Module, delivering four programmable relays for custom logic such as group alarms, trips, or permissive signals.
Are the relays hot-swappable? No. Change I/O modules with the rack powered down or with appropriate bypasses in place to prevent unintended equipment operation.
What condition is this unit? New Original / New Surplus. We inspect, power test, and verify basic relay operation before shipment.
How do I program the Alarm Drive Logic? Use 3500 Rack Configuration Software. Map alerts, dangers, or Not OK from any channels with AND/OR logic. Document existing logic before replacement.
What contact ratings should I respect? Follow datasheet limits (e.g., 2 A resistive). For inductive loads, use arc suppressors. Hazardous area versions have further restrictions.
Can I use multiple 125720-01 modules in one rack? Yes. Install as many as needed in available rear slots after the TDI. Each pairs with its own 3500/32 main module.
Any common pitfalls during installation? Ensure correct pairing with the main relay module. Verify Normally Energized/De-energized switch settings match your safety philosophy. Test all voting logic thoroughly after installation.
