I. Basic Information

Model: 72311-51-04-04-05-01-15 (Part Number) = 3500/42M (Commercial Model)

Series: Bently Nevada 3500 Mechanical Protection System

Form: Full-height card, occupying one full-height slot in the 3500 frame

Function Positioning: Axial displacement, temperature difference, eccentricity, phase monitoring (4 channels)

Current Status: Mainstream in use, core monitoring card of the 3500 system, compatible with the old 3500/42 model

II. Model Code Analysis (72311-XX-XX-XX-XX-XX-XX)

72311: Basic component number, fixed to represent the 3500/42M displacement monitoring card

-51: Hardware version (version 51, latest firmware)

-04: Number of channels (4 channels)

-04: Input type (electromagnetic induction probe, compatible with the 3300XL series)

-05: Output / Communication (with relay + RS232/485)

-01: Regional version (standard English)

-15: Calibration / Custom code (standard industrial-grade calibration)

III. Core Functions

4-channel independent monitoring: Simultaneously monitor 4 channels of axial displacement / temperature difference / eccentricity, suitable for rotating machinery such as steam turbines, compressors, and generators.

Electromagnetic induction probe compatibility: Compatible with 3300XL 8mm/11mm probes, measuring the gap between the shaft and the bearing, axial movement, and thermal expansion difference.

High-precision measurement: Displacement accuracy **±0.1μm**, temperature difference measurement range **±25mm**, eccentricity (XY dual probes) calculation supported.

Phase processing: Built-in phase signal conditioning, providing 1X/2X amplitude, phase, for vibration analysis and dynamic balance.

Alarm and protection: Two-level alarm (Alert/Danger) for each channel + relay output, capable of directly triggering the unit shutdown.

Data communication: Supports Modbus RTU/TCP, seamless integration with DCS/PLC/System 1 software.

IV. Technical Parameters

Slot: Full-height slot in the 3500 frame (left side priority)

Input: Electromagnetic induction probe (3300XL 8/11mm), phase signal

Channels: 4 channels (configurable as displacement / temperature difference / eccentricity)

Measurement range: Displacement 0–2mm; Temperature difference ±25mm; Eccentricity 0–500μm

Accuracy: Displacement ±0.1μm; Temperature difference ±1μm; Phase ±1°

Output: 4-channel relays (SPDT), RS232/485, Modbus

Power consumption: Typical 6.5W

Environment: Working 0℃~60℃, storage **-40℃~85℃**

Size (H×W×D): Approximately 250 × 85 × 150 mm

Weight: Approximately 1.2 kg

V. Differences from Similar Cards Table

Project 72311-xxx (3500/42M) 3500/40M (vibration) 3500/72 (piston rod)

Monitoring Object Rotating machinery shaft displacement / expansion difference Rotating machinery vibration (peak-to-peak / RMS) Reactor piston rod position

Sensor Electro-kinetic (non-contact) Electro-kinetic / speed / acceleration LVDT (contact type)

Channels 4 channels 4 channels 2 channels

Core Parameters间隙， runout， thermal expansion， eccentricity Operating frequency， 1X/2X， phase， kurtosis Position， settlement， tilt rate

Typical Applications Turbine， compressor， generator Blower， pump， motor， gearbox Petrochemical / natural gas reciprocating compressor

VI. Typical Applications and Combinations

Application Scenario: Axial displacement, expansion difference， eccentricity， phase synchronization monitoring for large rotating machinery such as steam turbines， centrifugal compressors， gas turbines， generators， etc.， to prevent shaft friction， collision， and excessive thermal expansion.

Typical Combinations：

3500/42M + 3500/15 (power supply)

3500/42M + 3500/22M (communication)

3500/42M + 3300XL 8mm probe (330103 series)

VII. Maintenance Points

Regularly calibrate the probe gap voltage (standard - 10V DC)

Check the insulation of the probe / extension cable (≥1MΩ)

Monitor the expansion difference trend， and issue an early warning for abnormal thermal deformation of the unit