Description
Note: Many products are not yet listed. Please contact us for more product information. Our supply channels are constantly expanding, and we currently have 20 stable shared supply channels. Please confirm the model, product, price, and all other necessary information with customer service before placing an order. We offer new, refurbished, and used products, and prices are adjusted according to the year of the item you require.
3. Product Introduction (Anti-Template)
Long copper runs on Modbus Plus networks pick up noise and limit distance. The 490NRP25400 solves that by bridging the electrical bus to fiber, regenerating the Bi-Phase S encoded signal at 1 Mbit/s.
It supports both bus and line-drop topologies, so one unit can extend a segment or create a remote drop without adding extra protocol converters. Plants running older Quantum or Momentum systems still rely on these repeaters because fiber keeps the network stable even when motors and drives sit nearby.
490NRP25400
490NRP25400
490NRP25400
490NRP25400
490NRP25400
4. Key Technical Specifications
| Parameter | Value |
|---|---|
| Network Protocol | Modbus Plus (MB+) |
| Data Rate | 1 Mbit/s (Bi-Phase S encoded) |
| Electrical Interface | 9-pin D-sub Modbus Plus connector |
| Optical Interface | ST-type fiber connectors |
| Power Supply | 115/230 VAC or 24 VDC |
| Function | Line/Drop Transceiver / Fiber Optic Repeater |
| Mounting | Panel or shelf |
| Operating Temperature | 0 °C to 60 °C |
| Storage Temperature | –40 °C to +85 °C |
| Typical Weight | Approx. 1.8–2.9 kg |
5. Field Application & Technical Pitfalls (The Engineer’s Guide)
This repeater shows up on long Modbus Plus backbones in water treatment plants, discrete manufacturing lines, and older Quantum PLC installations where copper segments cannot reach remote I/O drops. Fiber isolation also protects the bus from ground loops and EMI near large drives.
Three pitfalls appear during replacement:
Fiber type and connector mismatch – ST connectors are standard; mixing multimode and single-mode fiber or using the wrong polish produces high attenuation and intermittent CRC errors.
Power supply selection error – the unit accepts either AC or DC, but applying the wrong range or omitting proper grounding can damage the internal supply.
Topology and termination mistakes – placing the repeater without correct bus termination or mixing it into a non-supported drop configuration creates reflections that the rest of the network cannot tolerate.
One plant spent two days chasing phantom node losses after installing a replacement. The fiber jumper was the wrong grade; once the correct multimode ST cables were fitted and the optical power checked, the network stabilized within minutes.
6. Quality Control (QC) SOP & Transparency
- Inbound Verification – OEM labeling, serial number, and date codes are photographed and matched to the packing list; any signs of prior field use or rework are noted.
- Live Rig Testing – unit is powered on both AC and DC supplies, then exercised with a Modbus Plus traffic generator and optical loop-back to confirm link status, data throughput, and error-free regeneration.
- Parameter Testing – optical transmit/receive levels are measured; electrical interface continuity and isolation are verified.
- Final QA & Packaging – unit is sealed in an anti-static bag with desiccant, fitted with a QC-passed label showing test date and technician ID, then double-boxed for shipment.
7. Frequently Asked Questions (FAQ)
Can the 490NRP25400 be used on any Modbus network?
No. It is specific to Modbus Plus (MB+) running at 1 Mbit/s. Standard Modbus RTU or TCP requires different hardware.
Does it support both multimode and single-mode fiber?
The optical interface is designed around ST connectors. Confirm fiber type and distance limits with the original system documentation before installation; most installations use multimode for shorter runs.
What power options are available?
The unit accepts either 115/230 VAC or 24 VDC. Verify the actual supply voltage and polarity before energizing.
Is this a direct drop-in for older 490NRP series repeaters?
Mechanically and electrically it matches the common Modbus Plus fiber repeater footprint used in many Quantum systems. Always compare connector orientation and power terminal layout on the specific revision you are replacing.
What warranty comes with a new-surplus unit?
Twelve months from shipment against defects in materials and workmanship when installed within the published ratings.
How do I confirm the unit is functioning after installation?
Check the status LEDs for power and link, then verify node presence and error counters on the Modbus Plus network diagnostic tools. Any rise in CRC or timeout errors points to fiber quality, connector cleanliness, or termination issues.
