Description

Product Description

The Bently Nevada 3500/42 is a four-channel condition monitoring module engineered for continuous vibration and shaft position supervision within the 3500 machinery protection architecture. It processes inputs from proximity displacement probes as well as seismic velocity and acceleration sensors, converting raw signals into calibrated measurements for alarm evaluation and machinery diagnostics.

This module is widely applied across rotating equipment trains where both displacement-based and seismic-based monitoring are required in a single platform. It supports flexible configuration per channel, allowing operators to assign different measurement functions depending on machine dynamics and protection strategy.

System Function Overview

• Simultaneous monitoring of up to 4 independent channels

• Accepts proximity probes and seismic transducers in mixed configurations

• Real-time signal conditioning with digital filtering and scaling

• Continuous comparison against configurable alarm and danger thresholds

• Integration into 3500 rack architecture with dedicated I/O modules

Technical Specifications

Input Characteristics

• Channel count: 4 independent measurement channels

• Supported sensors:

• Eddy-current proximity systems (e.g., 3300 / 3300 XL / 7200 series)

• Velocity transducers

• Accelerometers (seismic input types)

• Input impedance:

• Proximity: ~10 kΩ

• Seismic: ~10 kΩ

• Typical power consumption: ~7.0 W

• Transducer compatibility: externally powered probe systems with conditioned return signals

Measurement Capabilities (Channel Configurable)
Each channel can be configured for:

• Radial vibration (shaft relative displacement)

• Thrust position (axial displacement monitoring)

• Eccentricity tracking

• Velocity measurement (seismic-based)

• Acceleration measurement

• REBAM dynamic vibration analysis mode

Signal Processing & Filtering

• Direct frequency band: 4 Hz to 4,000 Hz (standard configuration)

• Low-frequency option: 4 Hz to 600 Hz (application dependent)

• Gap filter cutoff: approximately −3 dB at 0.09 Hz (drift suppression)

• Not-1X filtering range: 60 cpm up to 15.8× running speed

• Vector filters (1X / 2X):

• Constant-Q response characteristics

• High attenuation outside passband (~−57 dB typical)

• Smax tracking: 0.125× to 15.8× running speed range

Outputs & System Interface

• Buffered analog outputs per channel via coaxial connectors

• Output impedance: ~550 Ω, short-circuit protected

• Front panel diagnostics:

• System OK status

• Rack communication (TX/RX)

• Bypass mode indication

• Relay outputs are handled externally via dedicated 3500 relay modules (e.g., 3500/32M, 3500/33)

Performance Characteristics

• Amplitude accuracy: typically within ±3% of full scale

• Phase accuracy: approximately ±2°

• Frequency response:

• Proximity inputs: DC to 4 kHz

• Seismic inputs: 4 Hz to 4 kHz

Environmental & Mechanical

• Operating temperature: −30°C to +65°C

• Relative humidity: up to 95% non-condensing

• EMC compliance: industrial-grade electromagnetic compatibility standards

• Module format: full-height 3500 series card

• Rack requirement: 2-slot configuration (monitor + I/O interface module)

Typical Applications

• Steam and gas turbine vibration monitoring

• Compressor train protection systems

• Pump and fan condition monitoring

• Power generation rotating machinery

• Oil & gas rotating equipment diagnostics

FAQ

Q: Can this module process both seismic and proximity inputs simultaneously?
A: Yes. Each channel can be independently assigned to either proximity or seismic measurement types depending on configuration.

Q: Does the 3500/42 include relay outputs?
A: No. Relay logic is implemented through external 3500 relay modules such as the 3500/33.

Specifications

• Brand: Bently Nevada

Advantages

• High reliability in industrial environments
• Supports continuous operation
• Compatible with major PLC/DCS systems