Description
Product Core Brief
- Model: 3500/42M-01-00 (Includes Monitor 176449-02 & I/O Module 128229-01)
- Brand: Bently Nevada
- Series: 3500 Machinery Protection System
- Core Function: Processes displacement, velocity, and acceleration sensor signals for comprehensive vibration and position monitoring.
- Product Type: 4-Channel Displacement/Velocity/Acceleration Monitor
- Key Specs: 4 Channels | Multi-Sensor Input | Internal Terminals | Software Configurable
- Condition: New Original (New Surplus)

BENTLY 3500/42M-01-00
Product Introduction
BENTLY 3500/42M-01-00 is a versatile 4-channel monitor module designed for the Bently Nevada 3500 Machinery Protection System. Unlike the standard 3500/40M, this module accepts inputs from eddy current proximity probes, seismic velocity sensors, and accelerometers.
This module continuously compares the processed signals against user-programmable alarm setpoints to protect rotating machinery. The 3500/42M-01-00 is highly flexible and can be configured via software to monitor radial vibration, axial displacement, eccentricity, differential expansion, REBAM, acceleration, velocity, absolute shaft vibration, and circular acceptable zones. Channels are configured in pairs to execute these functions.
Key Technical Specifications
- Module Type: 4-Channel Displacement/Velocity/Acceleration Monitor
- Form Factor: Full-Height
- Channels: 4 Independent Channels (Configurable in pairs)
- Supported Measurements: Radial Vibration, Axial Displacement, Eccentricity, Differential Expansion, REBAM, Acceleration, Velocity, Absolute Shaft Vibration, Circular Acceptable Zone
- Input Sensors: Proximitor (Eddy Current), Seismic Velocity, Accelerometers
- Outputs: Buffered Sensor Outputs (Front Panel Coaxial Connectors), 4-20 mA Recorder Outputs
- Indicators: OK LED, TX/RX LED, Bypass LED
- Software Requirements: 3500 Rack Configuration Software
Quality Control Process (Engineer’s Perspective)
- Incoming Verification: Trace source via serial number. Inspect front panel coaxial connectors and rear Euro-connector for physical damage.
- Visual Inspection: Verify OK, TX/RX, and Bypass LED indicators and module seating alignment.
- Live Functional Test: Install in rack. Verify “OK” LED illuminates and communication with RIM/TDI is established.
- Signal Path Test: Inject simulated proximity probe, velocity, or acceleration signal. Verify buffered output on front panel coaxial connectors and accurate measurement in software.
- Final QC & Packaging: Seal in anti-static bag. Apply QC Passed label with date.
Replacement Pitfall Guide
❗ Channel Pairing: The 3500/42M-01-00 channels are configured in pairs. Channels 1 and 2 execute one function, while channels 3 and 4 execute another (or the same) function. You cannot configure all 4 channels independently for different single-channel functions.
❗ Sensor Matching: This module accepts Proximitor, velocity, and acceleration sensors. Ensure the correct I/O module suffix matches your sensor type (e.g., -01 for internal terminals).
❗ Buffered Outputs: The front panel coaxial connectors provide buffered sensor outputs with short-circuit protection. These are useful for connecting portable data collectors or oscilloscopes without disrupting the monitor’s primary measurement path.
❗ Software Configuration: Alarm setpoints, filter settings, and measurement types are entirely software-driven. Ensure you have the correct 3500 Rack Configuration Software and a valid configuration file before commissioning.
❗ Bypass Mode: The Bypass LED indicates the module is in bypass mode. If this LED is illuminated during normal operation, check the software configuration and verify that no maintenance bypass commands are active.
Keep these in mind and you’ll cut 90% of rework time.

BENTLY 3500/42M-01-00
Compatibility Matrix & Benchmarks
- 3500/42M-01-00 → 3500/40M : Alternative — Use 3500/40M if only Proximitor inputs are required
- 3500/42M-01-00 → 3500/22M : Complementary — Requires TDI module for rack communication
- 3500/42M-01-00 → 3300 XL Probes : Compatible — Standard 5mm, 8mm, 11mm, 25mm proximity probes
- 3500/42M-01-00 → Seismic Sensors : Compatible — 3300 XL, 330180, 9200 series velocity/acceleration sensors
Benchmarks:
- Alarm Response Time: < 50 ms (typical)
- Buffered Output Impedance: 550 Ω (coaxial)
- Recorder Output: 4-20 mA proportional to full scale

