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SKU: 138708-01

Bently Nevada 138708-01 3500/40M Proximity Input I/O Module

The Bently Nevada 138708-01 is a 4-channel Proximity Input I/O Module with internal terminations for the 3500/40M monitor. It provides a direct-wire interface for vibration and position probes, featuring a wide operating temperature range and full industrial safety certifications.

System Purpose and Technical Function

The Bently Nevada 138708-01 acts as the primary hardware interface for the 3500/40M Proximity Monitor within the 3500 Machinery Protection System. This I/O module resides in the rear of the rack, where it accepts raw signals from proximity probes and transmits them to the monitoring card for processing. Because it features internal terminations, this module allows engineers to connect field wiring directly to its screw terminals without needing external terminal blocks. Consequently, the 138708-01 streamlines the installation of radial vibration, axial position, and Keyphasor measurement loops while reducing overall cabinet wiring complexity.

Core Technical Specifications

  • Brand: Bently Nevada
  • Part Number: 138708-01
  • Module Type: Proximity Input I/O with Internal Terminations
  • Compatible Monitor: Bently Nevada 3500/40M
  • Channel Support: 4-channel input configuration
  • Termination Style: Integrated screw terminal blocks
  • Operating Temperature: -40°C to +85°C
  • Humidity: 95% non-condensing
  • Hazardous Area Approvals: CSA, ATEX, and IECEx certified
  • Mounting Location: Rear slot of the 3500 series chassis

Operational Features and Industrial Application

Maintenance teams specify the 138708-01 I/O module for critical machinery oversight in power plants, refineries, and chemical processing facilities. The module provides highly stable signal paths for eddy current sensors, ensuring that electromagnetic interference (EMI) does not compromise the vibration data. Furthermore, the internal termination design includes dedicated grounding points for cable shields, which effectively prevents ground loops and signal noise. This reliability makes it an essential component for monitoring:

  • Radial shaft vibration in fluid-film bearings
  • Axial thrust displacement in steam turbines
  • Shaft eccentricity during startup and coast-down
  • Speed and phase reference via Keyphasor sensors

Installation and System Maintenance

Technicians install the 138708-01 directly behind the 3500/40M monitor module to establish a secure backplane connection. During the maintenance phase, the module’s rugged construction supports frequent wiring adjustments if sensor configurations change. Moreover, the unit allows for “hot-swapping” under redundant power conditions, meaning operators can replace an I/O module without shutting down the entire machinery protection rack. This feature significantly minimizes unplanned downtime and ensures continuous monitoring of high-value rotating assets.