The Bently Nevada 3500/90 (125728-01) functions as the primary digital bridge between the 3500 Machinery Protection System and external plant-wide networks. This high-performance gateway translates internal rack variables—including vibration magnitudes, temperatures, and alarm statuses—into industry-standard protocols. By supporting both Modbus RTU (Serial) and Modbus TCP/IP (Ethernet), it enables seamless data integration with Distributed Control Systems (DCS) and Programmable Logic Controllers (PLC). We offer this module as 100% Brand New and Original factory stock, ensuring the highest level of network stability for your critical assets.
| Parameter | Specification Details |
| Model Number | 3500/90 (125728-01) |
| Protocols Supported | Modbus RTU (RS-232/422/485) and Modbus TCP/IP |
| Ethernet Port | 1 x 10/100 Mbps RJ45 |
| Serial Interfaces | 2 x Configurable Serial Ports |
| Baud Rate Range | 1200 to 115.2 kbps |
| Security Architecture | Hardware-Enforced Read-Only Access |
| Data Types | Static Values, Alarms, Events, System Status |
| Operating Temp | -30 °C to +65 °C (-22 °F to +149 °F) |
| Dimensions | 24.1 cm x 3.8 cm x 24.1 cm |
Cybersecurity & Data Integrity: The 3500/90 employs a specialized read-only architecture. This hardware-level restriction ensures that network traffic from the DCS or external hackers cannot modify critical machinery protection setpoints or configuration logic.
Protocol Versatility: This module eliminates the need for external third-party protocol converters. It supports simultaneous serial and Ethernet communications, allowing legacy serial PLCs and modern Ethernet-based DCS systems to pull data concurrently.
Real-Time Diagnostics: Front-panel DIP switches facilitate rapid hardware addressing without requiring complex software tools during initial commissioning. The integrated system reset switch allows operators to clear latched alarms directly from the rack interface.
High Channel Density Integration: A single 3500/90 gateway provides access to all data within a 3500 rack. This minimizes hardware costs by centralizing the communication interface for up to 16 monitor modules into one dedicated gateway slot.
How does the 3500/90 protect the rack from unauthorized changes?
The module uses hardware-enforced "Read-Only" logic. While external systems can poll the gateway for vibration and status data, the gateway lacks the physical circuitry to write configuration changes back to the 3500 monitor modules.
Can I use both the Serial and Ethernet ports at the same time?
Yes. The 3500/90 supports concurrent communication. You can provide vibration data to a local HMI via Modbus RTU while simultaneously transmitting the same data to a centralized control room via Modbus TCP/IP.
What is the difference between the 125728-01 and earlier communication modules?
The 125728-01 is the modern high-speed version of the 3500/90. It offers improved processing power and Ethernet stability compared to legacy serial-only versions, providing faster data refresh rates for the DCS.
Does this module require a separate power supply?
No. The 3500/90 draws all necessary power directly from the 3500 rack backplane. It installs into any available slot in the rack, though it typically resides in the slot adjacent to the Power Supplies or Rack Interface Module (RIM).
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