Product Brief

3500/42M-01-00 is a Proximitor Seismic Monitor from Bently Nevada. It monitors vibration and position in rotating machinery. This module accepts 1 to 4 transducer signals. It works with proximity, velocity, or acceleration sensors. Use it for reliable machinery protection in critical assets.

Key Features at a Glance

• Channels: 1 to 4 inputs per module
• I/O Type: 01 – Prox/Seismic with internal terminations
• Transducer Support: Seismoprobe (recommended). Prox/Accel and Velomitor are supported but not recommended.
• Hazardous Area Approval: 00 = None
• Power Consumption: 7.7 watts typical
• Input Impedance: 10 kΩ for Proximitor and acceleration inputs
• Front Panel LEDs: OK, TX/RX, Bypass
• Buffered Outputs: Coaxial per channel, short-circuit protected
• Recorder Outputs: +4 to +20 mA, proportional to full scale
• Transducer Power Supply: -24 Vdc

Technical Specifications

• Brand & Model: Bently Nevada 3500/42M-01-00
  • Measurement Ranges (Sensitivity):
    • Radial Vibration / Thrust / Eccentricity: 3.94 mV/μm (100 mV/mil) or 7.87 mV/μm (200 mV/mil)
    • Differential Expansion: 0.394 mV/μm (10 mV/mil) or 0.787 mV/μm (20 mV/mil)
    • REBAM: 40 mV/μm (1000 mV/mil) or 80 mV/μm (2000 mV/mil)
    • Acceleration: 10 mV/(m/s²) (100 mV/g)
    • Velocity: 20 mV/(mm/s) pk, 5.8 mV/(mm/s) pk, or 4 mV/(mm/s) pk options
  • Frequency Response (Key Modes):
    • Radial Vibration Direct: -3 dB at 4 to 4000 Hz or 1 to 600 Hz (±1%)
    • Radial Vibration Gap: -3 dB at 0.09 Hz
    • Thrust Direct: -3 dB at 1.2 Hz
    • Eccentricity Direct: -3 dB at 15.6 Hz
    • Velocity RMS: 10 to 5500 Hz, -3 dB
  • Accuracy:
    • Direct & Gap: ±0.33% of full scale typical, ±1% max
    • 1X & 2X Vector: ±0.33% typical, ±1% max
    • Smax: ±5% max
  • Resolution (Recorder Output): 0.3662 µA per bit
  • Temperature Range: Specified at +25°C typical. Full operational range per Bently Nevada standard.
  • Environmental Tolerance: Designed for industrial panel use. Short circuit protection on outputs.
  • Noise Immunity: Built for harsh electrical environments. External barriers add minor error per datasheet.

Installation & Maintenance

• Installation Guide:
  • Fits standard 3500 rack. One slot width: 24.4 mm (0.96 in).
  • Use internal termination I/O module for easy wiring.
  • Connect transducers to front coaxial buffers or rear terminals.
  • Set sensitivity and filters via 3500 Rack Configuration Software.
• Debug & Maintenance Ease:
  • Front LEDs show OK, communication, and Bypass mode instantly.
  • Hot-swappable module. No need to power down the rack.
  • Recorder outputs are short-circuit proof – safe to test live.
• Compatibility:
  • Works with 3500 rack and Bently Nevada System 1 software.
  • Supports Seismoprobe, Velomitor, and proximity probes (with limits).
  • Not compatible with older 3300 series racks without adapter.

Certifications & Packaging

• Certifications: No hazardous area approval on this variant (00). Standard industrial safety.
• Package Includes:
  • 1 x 3500/42M-01-00 Monitor Module
  • 1 x I/O Module with internal terminations
  • No transducers included.
• Warranty: 12 months from shipment date. Covers manufacturing defects.
• Shipping:
  • Same day to 24 hours dispatch for in-stock units.
  • Carriers: FedEx, UPS, DHL. Express service available.

Expert Review

Manager’s Insight: This monitor delivers proven reliability for steam turbines, compressors, and gas turbines. Its flexible I/O accepts up to 4 channels, saving rack space. The -24V transducer supply and buffered outputs make field troubleshooting simple. For new installations, use Seismoprobe sensors as recommended. Avoid Velomitor with external barriers in high-EMI areas – accuracy may drop ±11% to ±15%. Overall, a solid choice for critical machinery protection.

Applicable Equipment & Scenarios

• Equipment:
  • Steam turbines
  • Gas turbines
  • Centrifugal compressors
  • Large pumps and fans
  • Generators
• Scenarios:
  • Radial vibration monitoring
  • Thrust position and differential expansion
  • Shaft eccentricity during startup
  • REBAM (rolling element bearing) monitoring
  • Absolute shaft vibration (case + relative)

Frequently Asked Questions (FAQ)

• Can I use this module with a Velomitor sensor?Yes, but Bently Nevada does not recommend it. Accuracy may be lower in noisy environments. Use Seismoprobe for best results.
• Does it support 4 channels of proximity probes?Yes. The I/O type 01 accepts up to 4 proximity, velocity, or acceleration inputs.
• What is the output impedance of buffered outputs?550 Ω for standard channels. For Shaft Absolute outputs, it is 300 Ω.
• How do I know if the monitor is working?Check the green OK LED. If it is on, the module operates properly.
• Can I replace it while the rack is powered?Yes. The 3500 series supports hot-swap. No need to shut down.
• What is the recorder output range?+4 to +20 mA. It is proportional to the monitor full scale per channel. Short circuits do not affect monitor operation.

Selection Guide – How to Choose the Right Variant

• • Step 1: Confirm your transducer type.Use Seismoprobe for new designs. For existing Velomitor or proximity probes, expect lower recommended status.
  • Step 2: Choose I/O module type.01 = internal terminations (easiest wiring). Other types exist for external barriers.
  • Step 3: Check hazardous area need.This 00 version has no approval. For Zone 2/Div 2, select other suffix.
  • Step 4: Match sensitivity to your sensor.Radial vibration: 100 mV/mil or 200 mV/mil. Set in software.
  • Step 5: Verify filter requirements.Need 1X/2X vector or Smax? This monitor supports all standard filters.
  • Step 6: Plan for spares.Keep one extra module per rack for critical assets. 12-month warranty included.