Bently Nevada 3500/72M 140734-08 Proximitor Monitor

Monitor Overview

The Bently Nevada 3500/72M 140734-08 proximitor monitor provides precise shaft displacement measurement for 3500 series machinery protection systems. This high-performance module interfaces directly with eddy current proximity probes. It converts gap voltage into engineering units for position monitoring and protection. Reliability engineers depend on this monitor for critical turbomachinery applications like thrust position and differential expansion.

Input Channel Configuration

The Bently Nevada 3500/72M 140734-08 features 2 independent input channels for dual-probe configurations. Each channel supplies regulated -24 V DC excitation for eddy current probes. The module accepts signals from 5 mm, 8 mm, and 14 mm probe systems. Separate conditioning circuitry exists for each channel. This dual-channel design supports redundant or dual-plane measurements.

Measurement Range and Sensitivity

The module measures shaft displacement across a 0 to 2 millimeter standard range. It achieves a resolution of 0.002 millimeters for precise shaft tracking. The input sensitivity adjusts from 2 to 10 millivolts per micrometer. Each channel includes programmable scaling for direct engineering units. This flexibility accommodates various probe calibration constants.

Output Signaling and Alarm Functions

The Bently Nevada 3500/72M 140734-08 provides two 4-20 mA analog outputs for system integration. It includes 4 alarm relays for alert and danger setpoints across both channels. Each channel offers independently adjustable trip levels. The module also supplies buffered probe signals for diagnostic connectivity. These outputs enable comprehensive shaft position monitoring.

Signal Processing and Filtering

The module incorporates adjustable band-pass filtering for effective noise rejection. Low-pass filters range from 0.5 to 10 hertz for position measurements. A high-pass filter removes DC drift from signal conditioning. The module provides averaging for stable gap readings. This processing ensures accurate proximity measurements.

Communication and System Integration

The Bently Nevada 3500/72M 140734-08 interfaces through the 3500 rack backplane. It exchanges data with the system controller for alarm management. The module supports 3500 configuration software for parameter setting. It provides Modbus communication for external monitoring. This integration fits seamlessly into machinery protection systems.

Physical Dimensions and Installation

The monitor measures 65 millimeters in width, 150 millimeters in height, and 120 millimeters in depth. The unit weighs 0.5 kilograms for straightforward insertion. It plugs directly into any 3500 rack slot. The module requires no additional mounting hardware. This design simplifies field replacement and maintenance.

Power Consumption and Heat Dissipation

The Bently Nevada 3500/72M 140734-08 draws 130 milliamperes from the backplane supply. It dissipates approximately 4.5 watts during typical operation. The aluminum enclosure aids natural convection cooling. This low power design suits dense rack configurations.

Diagnostic and Status Indication

Front-panel LEDs display power, communication, and channel status clearly. A green OK LED confirms normal module operation and configuration. Each channel has dedicated alarm and danger indicator LEDs. The module sends diagnostic codes to the system controller. These indicators enable quick identification of measurement problems.

Environmental Specifications

The monitor operates from -20°C to +65°C ambient temperature. It withstands 10% to 95% non-condensing humidity conditions. The unit meets ISA S71.04 environmental standards for industrial use. The conformal-coated PCB resists moisture and contaminants. The robust design handles industrial vibration.

Technical Specifications Table