Description

Product Description

The Bently Nevada 3500/42-125672-02 is a four-input channel monitoring module designed for integrated vibration and shaft position supervision within the 3500 protection system. It processes both proximity displacement and seismic sensor signals, converting them into calibrated engineering data used for machinery protection and condition diagnostics.

The unit is engineered for API 670-compliant monitoring architectures and is typically deployed on critical rotating equipment where multi-parameter vibration analysis and shaft behavior tracking are required.

Monitoring Capabilities

The module supports a broad range of measurement functions, configurable per channel pair:

• Radial shaft vibration

• Axial thrust position

• Shaft eccentricity

• Differential expansion

• Velocity-based casing vibration

• Acceleration monitoring

• REBAM dynamic vibration analysis

• Shaft absolute measurement

• Circular acceptance region evaluation

Channel pairing allows simultaneous execution of two measurement functions per pair, enabling flexible protection logic for complex machinery dynamics.

Input & Electrical Characteristics

• Total channels: 4 independent inputs

• Sensor compatibility:

• Eddy current proximity probe systems

• Velocity transducers

• Accelerometers (seismic sensors)

• Typical power draw: ~7.7 W

• Input impedance:

• ~10 kΩ for proximity and acceleration inputs

• Rack-powered module (nominal 24 VDC supply via 3500 system backplane)

Measurement Scaling & Sensitivity

• Radial / thrust / eccentricity:

• 3.94 mV/µm or 7.87 mV/µm

• Differential expansion:

• 0.394 mV/µm or 0.787 mV/µm

• REBAM mode:

• 40 mV/µm or 80 mV/µm

• Acceleration input:

• 10 mV/(m/s²) ≈ 100 mV/g

• Velocity input:

• Multiple selectable ranges (typical 4–20 mV/mm/s peak equivalents depending on configuration)

Signal Processing

• High-resolution digital conditioning with programmable scaling

• Real-time alarm evaluation against alert and danger thresholds

• Supports multiple filtering and diagnostic algorithms depending on configuration

• Designed for stable long-term operation in continuous monitoring environments

Outputs & Diagnostics

• Individual buffered analog outputs per channel (coaxial interface)

• Output protection: short-circuit resistant

• Front panel indicators:

• System status (OK)

• Communication activity (TX/RX)

• Bypass mode indication

• No onboard relay outputs; external relay logic handled via dedicated 3500 relay modules

Mechanical & Physical Data

• Dimensions: 241.3 × 24.4 × 241.8 mm

• Weight: 0.91 kg

• Installation: 3500-series rack mounted, hot-swappable design

• Ruggedized industrial card form factor for continuous service operation

Environmental Ratings

• Operating temperature: −20°C to +65°C

• Storage temperature: −40°C to +85°C

• Relative humidity: 10% to 95% non-condensing

• Vibration tolerance: up to 2 g (5–200 Hz range)

• Shock resistance: 15 g, 11 ms pulse

• Protection class: IP20 (rack-dependent enclosure conditions)

Compliance & Reliability

Designed in accordance with API 670 machinery protection requirements, ensuring compatibility with standardized turbine and rotating equipment protection architectures. The module supports hot-swap replacement without system shutdown when installed in a compliant 3500 rack.

Typical Applications

• Steam and gas turbines

• Centrifugal and axial compressors

• Industrial pumps and fans

• Power generation rotating trains

• Oil & gas processing machinery

FAQ

Q: Can this module handle both seismic and proximity inputs simultaneously?
A: Yes. Each channel pair can be configured to process different sensor types depending on monitoring requirements.

Q: Does the module include built-in relays?
A: No. Alarm relay functions are handled by separate 3500 relay modules within the rack system.

Specifications

• Brand: Bently Nevada

Advantages

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