Product Overview

The Bently Nevada 3500/32 Relay Module, specifically part number 125712-01, is a high-reliability hardware component designed for the 3500 Series Machinery Protection System. This module provides four independent relay outputs that are used to trigger external alarms, sirens, or automated machinery shutdown sequences based on programmed setpoints. By converting digital alarm signals into physical contact closures, the 125712-01 serves as the critical safety interface between vibration monitoring logic and plant-wide emergency control circuits.

Each of the four channels is highly configurable to meet specific operational safety protocols. The module utilizes a "voted" logic approach when integrated with 3500 series monitors, allowing for complex protection schemes like AND/OR logic. Its primary role is to ensure that critical industrial assets—such as turbines, compressors, and large motors—are immediately protected when mechanical vibration or position limits are exceeded.

Relay Configuration and Signaling

The 125712-01 features four relay channels, where each channel consists of two single-pole, double-throw (SPDT) relays arranged in a double-pole, double-throw (DPDT) architecture. This redundancy provides superior switching reliability for critical safety loops. The relays are user-selectable via onboard switches for either "Normally Energized" (fail-safe) or "Normally De-energized" operation.

For instantaneous field diagnostics, the module is equipped with a comprehensive LED array. The "OK" status LED confirms the internal health of the module, while the "TX/RX" indicators monitor active data communication with the 3500 rack backplane. Individual "CH ALARM" LEDs provide immediate visual confirmation of which specific relay channel has been tripped, significantly reducing troubleshooting time during an event.

Technical Specifications

• Model Identification: 3500/32

• Spare Part Number: 125712-01

• Relay Quantity: 4 independent channels

• Relay Type: SPDT (wired as DPDT configuration)

• Contact Rating: 5 A @ 24 Vdc or 120 Vac

• Service Life: 100,000 cycles at rated load

• Operating Logic: Switch selectable (Normally Energized/De-energized)

• Status Indicators: OK, TX/RX, and Channel Alarm LEDs

• Environmental Range: -30°C to +65°C (-22°F to +150°F)

• Storage Limits: -40°C to +85°C (-40°F to +185°F)

• Net Weight: 0.7 kg (1.6 lb)

• Chassis Dimensions: 24.18 cm x 2.44 cm x 24.18 cm

• Manufacturing Origin: USA

Industrial Safety Applications

• Machinery Protection: Triggering emergency trips for turbines and pumps during high-vibration events.

• Alarm Annunciation: Activating local and remote visual or audible indicators for plant operators.

• Control System Integration: Providing dry contact feedback to a Distributed Control System (DCS) or PLC.

• Automated Shutdowns: Managing fail-safe logic for critical infrastructure in oil and gas, power generation, and chemical processing.