Bently Nevada 3500/42-I-01 Proximitor/Seismic Monitor – 4‑Channel Vibration Protection for Critical Machinery

The Bently Nevada 3500/42-I-01 is a 4‑channel Proximitor/Seismic monitor used in 3500 racks to provide continuous vibration, position, and casing motion protection on rotating assets. It’s typically deployed on compressors, steam and gas turbines, large motors, and critical pumps where API 670-grade protection and reliable trending are non-negotiable. From my experience, plants choose this module when they want proven trip integrity with flexible transducer support and easy integration into System 1.

• 4 channels, proximitor/seismic inputs – supports eddy-current proximity probes (shaft vibration/position) and seismic transducers (velocity or acceleration) on one module.

• Protection-grade alarming – dual setpoints per channel (Alert/Danger) with configurable voting and alarm delay, suited for API 670 protection strategies.

• Flexible measurement processing – bandpass filtering, integration (accel to velocity, velocity to displacement), gap measurement, and amplitude/phase when used with a Keyphasor reference.

• Buffered signal outputs – front-access buffered outputs per channel for portable analyzers and diagnostics without disturbing the process.

• Optional 4–20 mA outputs (by I/O option) – mirror key parameters to the DCS or PLC where needed without extra converters.

• Tight System 1 integration – configuration and data collection via the rack’s 3500/22M TDI over Ethernet; no separate data modules required.

• Backplane-powered, rack-based design – no external power at the monitor, which simplifies panel wiring and improves reliability.

• Broad transducer compatibility – works with Bently Nevada 3300/330500 proximity and velocity sensors, and commonly used industrial IEPE accelerometers (per module options).

You’ll typically see the 3500/42-I-01 protecting high-value rotating machinery:

• Refining and petrochemical: process compressors, charge pumps, coker blowers

• Power generation: steam/gas turbines, generator bearings, feedwater pumps

• Upstream and midstream: gas compression trains, pipeline stations

• Pulp & paper, mining, metals: large motors, fans, mills with casing vibration/shaft displacement

• OEM test stands and revamp projects needing API 670-compliant protection

• Proven reliability – long field history in harsh environments; in many cases, units run for years with only routine checks.

• Compatibility that reduces risk – works with widely used Bently Nevada probes and standard IEPE devices; simplifies spares and documentation.

• Lower lifecycle cost – shared rack power, modular I/O, and reconfigurable logic mean less panel space and faster changeovers.

• Data you can trust – buffered outputs and System 1 connectivity make troubleshooting faster without taking the machine offline.

“We swapped a mixed OEM setup for 3500/42 monitors on our cracked-gas compressors. The buffered outputs alone shaved hours off vibration diagnostics,” — Maintenance Lead, petrochemical site.

• Panel/cabinet: mount in a 3500 rack within a clean, ventilated enclosure; allow front access for status LEDs and buffered jacks; maintain ambient within the specified range.

• Wiring: route transducer cables separately from power; maintain shield integrity and proper grounding; observe proximitor cable lengths per sensor datasheet.

• Keyphasor: for 1X amplitude/phase and speed-dependent alarms, provide at least one Keyphasor input in the rack.

• Commissioning: verify gap voltage on proximity probes, run-channel checks, and alarm setpoint validation; confirm trend points in System 1/DCS.

• Maintenance: periodically clean connectors, re-torque terminal screws, and review alert/danger logs; typically, annual probe calibration checks are sufficient.

• Firmware/config: keep rack firmware aligned with plant standards; back up 3500 configuration files after any change.

• Spares: hold at least one spare monitor and matching I/O per rack; stocking a spare proximitor and velocity sensor reduces downtime in most cases.

• CE-marked; UL/cUL approvals are available for the 3500 series modules

• Designed for API 670 compliant protection architectures

• Manufacturer quality system typically ISO 9001

• Standard manufacturer warranty (commonly 1 year); extended service agreements available

You might notice the “-I-01” option code; it usually defines a specific I/O style and configuration. If you share your installed transducer types and whether you need 4–20 mA outputs, I can confirm the exact I/O module match and provide a final BOM with lead times.