BENTLY 3500/42M 176449-02 — Multi-channel Proximitor/Seismic Monitor for Critical Machinery Protection

The BENTLY 3500/42M (assembly variant 176449-02) is a four-channel monitor designed for continuous vibration and position measurement in the 3500 rack. From my experience, this is the go-to card when you need reliable radial vibration, thrust position, or casing seismic measurements tied directly to API-compliant protection logic. It interfaces with proximity probes and seismic transducers, drives Alert/Danger alarms, and integrates cleanly with 3500 relays for trip voting. You might notice that it also provides buffered outputs for portable data collectors and supports phase-referenced measurements when a Keyphasor module is present.

Company’s Order Placement Process and Guarantees

• Warranty: 365 days standard coverage
• Lead time: 1 week if in stock; no more than 1 month at the latest
• Payment: 50% advance payment; full payment prior to delivery
• Express options: FedEx, UPS, DHL

Key Features

• 4 independent channels – Monitors vibration or position using Proximitor (eddy-current) and seismic sensors (velocity or accelerometer).
• Machinery protection logic – Configurable Alert/Danger setpoints with latched alarms, voting, and trip integration via 3500 relay modules.
• Buffered transducer outputs – Convenient BNC access at the I/O for portable analyzers and scope checks.
• Phase-referenced measurements – Supports 1X amplitude/phase and diagnostics when paired with a 3500/25 Keyphasor module.
• Flexible measurement types – Radial vibration, thrust position, shaft-relative measurements, and casing velocity/acceleration as required.
• Rack-level integration – Works with 3500/22M TDI for Ethernet communications, and 3500/33 or 3500/32 modules for relays or 4–20 mA outputs respectively.
• Hot-swappable front card – Front module pairs with a matching rear I/O module for fast maintenance in most cases.

Technical Specifications

Application Fields

Typically used on steam and gas turbines, compressors, large motors, pumps, fans, gearboxes, and generators. In many cases, the 3500/42M takes the lead channels for radial vibration and thrust position, while the rack’s relay modules handle shutdown logic. A maintenance lead at a combined-cycle plant told us they swapped in the 42M during a planned outage and immediately saw more stable alert thresholds on a critical compressor train, with cleaner buffered signals for route-based analysis.

Advantages & Value

• Reliability – Proven monitor within the 3500 platform; seems to be the standard in many plants for continuous protection.
• Compatibility – Works with common Proximitor probe systems (5 m / 9 m / 14 m) and seismic sensors; integrates with Keyphasor, relay, and TDI modules.
• Lifecycle cost – Shared rack infrastructure, hot-swap design, and reusable transducer wiring can reduce downtime and retrofitting costs.
• Data accessibility – Buffered outputs and Ethernet access via TDI support quick diagnostics and connection to condition monitoring software.
• Scalability – Start with protection channels and extend to plant interfaces (Modbus TCP) or 4–20 mA outputs using 3500/32 if required.

Installation & Maintenance

• Cabinet & environment – Mount modules in a clean, ventilated control cabinet; maintain ambient temperatures within spec and allow airflow around the rack.
• Wiring – Use shielded twisted-pair per Bently Nevada guidelines; maintain probe/cable lengths (e.g., 5 m, 9 m, 14 m systems) and ensure solid grounding to minimize noise.
• Commissioning – Verify probe gaps and polarity, perform static and dynamic checks, configure Alert/Danger setpoints, and validate relay voting if used.
• Routine maintenance – Periodically review trends and alarm logs, clean connectors, confirm buffered output signal quality, and back up configurations via 3500/22M.
• Firmware & calibration – Keep rack/module firmware aligned with plant standards; check transducer calibration status during scheduled outages.
• Safety – De-energize affected channels when moving wiring on the I/O; follow lockout/tagout procedures and observe ESD precautions.

Quality & Certifications

The 3500 series typically carries CE and UL/cUL certifications, with RoHS compliance on most current builds. Exact approvals may vary by rack and I/O option set, so we can confirm documentation for the specific 176449-02 configuration. Standard warranty is 365 days.