Description

Product Description

The Bently Nevada 3500/42M is a four-channel machinery protection and condition monitoring module designed for continuous acquisition and processing of vibration, displacement, and dynamic motion signals. It interfaces with proximity probes and seismic sensors, converting raw transducer inputs into calibrated diagnostic parameters used for machinery protection and condition assessment.

The module operates within the Bently Nevada 3500 rack system and is typically applied in high-integrity rotating equipment monitoring environments where real-time fault detection and shutdown protection logic are required.

Measurement Capabilities

Each input channel can be independently assigned to one of several monitoring functions. Channel pairs support dual-function operation for enhanced flexibility in machinery diagnostics.

Supported measurement types include:

• Radial shaft vibration

• Axial thrust position

• Shaft eccentricity

• Differential expansion monitoring

• Casing velocity vibration

• Acceleration response analysis

• REBAM vibration detection

• Shaft absolute displacement

• Circular acceptance region evaluation

This configuration enables simultaneous analysis of shaft dynamics and casing behavior across multiple measurement domains.

Input Configuration & Electrical Characteristics

• Total channels: 4 independent inputs

• Sensor compatibility:

• Eddy-current proximity probes

• Velocity transducers

• Accelerometers

• Input impedance:

• Standard configuration: 10 kΩ

• TMR configuration: approximately 50 kΩ (bussed architecture)

• Typical power consumption: ~7.7 W

• Designed for rack-supplied operation within 3500 system backplane

Signal Processing & Filtering

• Frequency response options:

• 4 Hz to 4000 Hz (standard mode)

• 1 Hz to 600 Hz (low-frequency configuration)

• Gap filtering: −3 dB at approximately 0.09 Hz for baseline drift suppression

• Not-1X suppression band: 60 cpm to 15.8× running speed

• Vector filtering (1X / 2X):

• Constant-Q response architecture

• High rejection performance (~−57.7 dB typical)

• Circular acceptance region processing derived from radial vibration vector analysis

Measurement Scaling & Sensitivity

• Radial / thrust / eccentricity:

• 3.94 or 7.87 mV/µm

• Differential expansion:

• 0.394 or 0.787 mV/µm

• REBAM mode:

• 40 or 80 mV/µm

• Acceleration:

• 10 mV/(m/s²) ≈ 100 mV/g

• Velocity:

• 20 / 5.8 / 4 mV/(mm/s) peak (configuration dependent)

• Shaft absolute displacement:

• 3.94 or 7.87 mV/µm

Outputs & System Indicators

• Buffered analog outputs via individual coaxial connectors per channel

• Short-circuit protected output design

• Front-panel diagnostics:

• System status (OK)

• Communication activity (TX/RX)

• Bypass mode indication

• External relay logic handled through separate 3500 relay modules

Reliability & Operating Design

• Continuous-duty machinery protection architecture

• High stability signal conditioning for long-term monitoring

• Designed for integration into safety-critical rotating equipment systems

• Supports redundant system configurations when deployed in TMR architectures

Typical Applications

• Gas and steam turbine monitoring systems

• Centrifugal and axial compressors

• Industrial pump and fan trains

• Power generation rotating machinery

• Oil & gas process equipment

FAQ

Q: Can each channel perform different measurement functions?
A: Yes. Channels are independently configurable, and paired channels can execute dual measurement functions simultaneously.

Q: Does the module support both displacement and vibration analysis?
A: Yes. It processes proximity-based displacement along with seismic velocity and acceleration signals.

Specifications

• Brand: Bently Nevada

Advantages

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