1. General Information

• Manufacturer: Bently Nevada (Baker Hughes)

• Model Number: 3500/40M

• Main Board Part Number: 176449-01

• Rear I/O Board: 125680-01 (Built-in Internal Termination Board)

• Product Name: Four-Channel Proximitor Monitor Module

• Series: 3500 Machinery Protection System

• Module Type: Full-height proximity dedicated monitoring main board

• Application: Specialized displacement monitoring board for eddy-current probes; monitors shaft radial vibration, thrust position, eccentricity and REBAM; widely used for steam turbine, compressor high-speed rotating machinery protection.

• Installation Rule: Any full-height slot inside 3500 rack

• Compliance: API 670

2. Functional Description

• Channel Configuration: 4 independent input channels, configurable in pairs (Ch1-2 / Ch3-4)

• Supported Sensor: Only Eddy-current proximity probe (No seismic sensor)

• Monitoring Parameter: Radial Vibration, Thrust Position, Eccentricity, REBAM

• Alarm Logic: Independent Alert & Danger setpoints per channel

• Signal Processing: High precision dynamic signal filtering for shaft displacement

3. Electrical Specifications

• Backplane Power: +5 VDC from rack backplane

• Power Consumption: 10.5 W typical

• Sensor Power: -24 VDC dedicated probe power supply

• Frequency Response: 0.5 Hz ~ 10 kHz

• Analog Output: 4-channel isolated 4-20mA, Max 600 Ω load

• Isolation Voltage: 1500 VAC channel-to-system isolation

• 4. Environmental Specifications

  • Operating Temperature: -30 °C ~ +65 °C (-22 °F ~ +149 °F)

  • Storage Temperature: -40 °C ~ +85 °C (-40 °F ~ +185 °F)

  • Relative Humidity: 5% ~ 95% (Non-condensing)

  • Anti-vibration: Compliant with API 670 industrial vibration standard

  5. Mechanical Specifications

  • Structure: Full-height single slot monitoring module

  • Dimensions (H × W × D): 241.3 × 24.4 × 241.8 mm

  • Weight: Approximately 0.91 kg

  • Mounting: Hot-swap capable, internal terminal integrated design

  6. Compatible Devices

  • Matching Rear Board: 125680-01 (Exclusive built-in I/O board)

  • Applicable Probe: Standard Bently eddy-current proximity probe series

  • Rack Chassis: All standard 3500 series racks

  7. Key Features

  • Pure proximity probe dedicated board, optimized for shaft displacement signal

  • Dual-group pairing configuration for flexible measuring modes

  • High stability low-drift circuit for long-term turbine monitoring

  • Integrated internal terminal without external rear board

  • API 670 compliance for critical rotating machinery protection

  8. Pairing & Classification (Most Important)

  • 176449-01: 3500/40M Main Board (Signal acquisition & logic calculation).

  • 125680-01: 3500/40M Internal I/O Board (Field wiring terminal).

  • 40M: Only proximity probe (Displacement) | 42M: Probe + Seismic vibration.