The 3500/40 Eddy Current Monitoring I/O Module (135489-04) is part of the Bently Nevada 3500 Machinery Protection and Condition Monitoring System. It provides four independent channels for eddy current sensor inputs and integrates internal intrinsic safety barriers and internal field terminals, making it especially suitable for hazardous-area installations while simplifying field wiring and maintenance.

This module supports a wide range of proximity-based mechanical measurements and delivers high-reliability signal conditioning, isolation, and alarm processing for critical rotating machinery.

Technical Specifications
System Compatibility

System: Bently Nevada 3500 Machinery Protection and Condition Monitoring System

Rack Compatibility: Standard 3500 rack

Channel Configuration

Number of Channels: 4 independent eddy current input channels

Sensor Support:

Compatible with Bently Nevada 3300 and 3500 series eddy current sensors

Sensor Sensitivity:

3.94 mV/µm (100 mV/mil)

7.87 mV/µm (200 mV/mil)

Sensor Power

Supply Voltage: −24 V DC ±10%

Power Distribution: Independent power supply per channel

Signal Characteristics

Frequency Bandwidth: 4 Hz to 4 kHz (standard)

Input Impedance: 550 Ω

Electrical Isolation & Safety

Isolation: Electrical isolation between channels and between system and field circuits

Safety Barrier:

Integrated intrinsic safety barriers per channel

Suitable for hazardous-area and explosion-risk environments

Power Consumption

Typical Power Consumption: Approx. 7 W

Environmental Conditions

Operating Temperature: −30 °C to +65 °C

Storage Temperature: −40 °C to +85 °C

Mechanical Characteristics

Dimensions (W × H × D):
50.8 mm × 120.7 mm × 251.5 mm (standard 3500 rack form factor)

Weight: Approx. 1.39 kg

Core Features
Integrated Intrinsic Safety Design

Built-in channel-level safety barriers provide intrinsic safety protection, enabling direct connection to sensors in hazardous areas while isolating field signals from system electronics and reducing explosion risk.

Simplified Internal Terminal Wiring

Integrated internal terminals eliminate the need for external junction boxes, reducing field wiring complexity, minimizing potential fault points, and improving installation and maintenance efficiency.

Multi-Parameter Monitoring Capability

Supports a wide range of machinery measurements, including:

Radial vibration

Axial (thrust) displacement

Shaft eccentricity

Differential expansion

Other proximity-based measurements

This flexibility allows adaptation to diverse rotating equipment monitoring requirements.

Programmable Alarm Management

Each channel supports configurable Alert and Danger alarm thresholds, which can be managed through the 3500 rack configuration software to implement flexible protection and condition monitoring strategies.

Status Indication and Diagnostics

Front-panel LED indicators provide clear visual status for:

Module OK

Communication status

Bypass condition

Channel-related faults

This enables rapid fault localization and reduced maintenance downtime.

System Integration and Data Access

Fully compatible with 3500 series racks and communication modules, supporting integration with higher-level systems for remote monitoring, diagnostics, and data management.

Typical Applications

Hazardous-area vibration and position monitoring

Gas and steam turbine machinery protection

Compressors, pumps, and large rotating equipment

Condition-based maintenance and predictive diagnostics systems

Industrial installations requiring intrinsic safety and high signal integrity

BENTLY 3500/40 135489-04 Proximitor I/O Module