BENTLY 126648-01 Isolated Keyphasor I/O Module for 3500 Series Machinery Protection

Brand Bently Nevada

Model BENTLY 126648-01

Product Overview

The BENTLY 126648-01 is a dual-channel Keyphasor I/O module engineered specifically for the Bently Nevada 3500 Series Machinery Monitoring System, serving as the critical interface between shaft reference transducers and the 3500/25 Enhanced Keyphasor Monitor. As a fundamental component within the 3500 platform, the BENTLY 126648-01 accepts input signals from proximity probes or passive magnetic pickups and converts them into precise digital Keyphasor pulses that indicate when the Keyphasor mark on a rotating shaft passes the transducer. This timing reference is indispensable for accurate measurement of rotational speed, 1X vibration amplitude, and phase angle, which together form the foundation of machinery diagnostics and protection strategies for turbines, compressors, and other critical rotating equipment.

The BENTLY 126648-01 features external terminations, meaning field wiring connections are made to a terminal strip rather than directly to the module backplane, offering greater flexibility in cable routing and maintenance access. The module supports two independent input channels, enabling simultaneous monitoring of two separate machine shafts or two Keyphasor marks on a single shaft for multi-event-per-turn applications. Its isolated design provides electrical separation between the Keyphasor signal and other systems, preventing ground loops and signal interference when the Keyphasor output must be shared with non-Bently Nevada devices such as PLCs or distributed control systems.

Positioned as an essential I/O component within the 3500 Series architecture, the BENTLY 126648-01 works in concert with the 3500/25 Enhanced Keyphasor Module to deliver reliable speed and phase data to monitor modules throughout the rack. Its backward-compatible form factor ensures seamless integration into both new installations and legacy 3500 systems, while enhanced signal processing capabilities support modern diagnostic requirements. The module’s robust construction and wide operating temperature range make it suitable for deployment in power generation, oil and gas, and heavy industrial environments where continuous machinery monitoring is mission-critical.

Request Price

Description

Technical Specifications

Parameter Name	Parameter Value
Product Model	BENTLY 126648-01
Manufacturer	Bently Nevada
Product Type	Keyphasor I/O Module (External Terminations)
Compatible Monitor	3500/25 Enhanced Keyphasor Module
Input Channels	2 Independent Channels
Signal Input Types	Proximity Probes, Magnetic Pickups
Input Signal Range (Non-Isolated)	+0.8 V to -21.0 V
Input Signal Range (Isolated)	+5 V to -11 V
Minimum Speed (Magnetic Pickup)	200 rpm (3.3 Hz)
Input Impedance	≥21.8 kΩ
Output Impedance	≤504 Ω
Power Consumption	3.2 W (Typical)
Operating Temperature	-30°C to +65°C
Storage Temperature	-40°C to +85°C
Dimensions (H×W×D)	241.3 mm × 24.4 mm × 103.1 mm
Weight	0.46 kg
Agency Approvals	ATEX, CSA, IECEx
Rack Space	1 Full-Height Rear Slot

Main Features and Advantages

The BENTLY 126648-01 distinguishes itself through a combination of signal processing precision, operational flexibility, and system integration capabilities that address the practical demands of machinery protection applications. Its dual-channel architecture allows a single module to handle two independent Keyphasor inputs, whether from separate shafts in a multi-train installation or from two Keyphasor marks on one shaft for enhanced rotational resolution. This capability reduces the number of modules required per rack, conserving valuable slot space for other monitoring functions.

Isolation: The BENTLY 126648-01 is available in an isolated configuration that provides electrical separation between input and output circuits, a feature specifically designed for applications where the Keyphasor signal must be shared with external control systems. This isolation prevents ground loops and signal degradation that can occur when a single transducer signal is routed to multiple destinations with different ground references. For magnetic pickup applications, the isolated version is often the preferred choice, though it remains compatible with proximity probes when external power is provided.

Signal Processing and Outputs: The BENTLY 126648-01 delivers buffered Keyphasor signals through coaxial connectors on the front panel and Euro-style connectors on the rear of the rack, providing flexible interface options for both local diagnostics and system-wide distribution. The module’s high input impedance of 21.8 kΩ minimum ensures minimal loading of the transducer signal, preserving signal integrity across the full input range. With a response time designed for real-time speed tracking, the BENTLY 126648-01 maintains accurate pulse timing even during rapid speed changes, supporting reliable overspeed protection and transient event capture.

System Compatibility and Maintenance: The BENTLY 126648-01 is fully compatible with the 3500 Series monitoring framework and maintains backward compatibility with legacy Keyphasor module designs, allowing direct replacement in existing installations without system redesign. Its external termination design simplifies field wiring changes and module replacement, as connections are made to accessible terminal strips rather than directly to the backplane. The module operates without requiring routine calibration, and its hot-swap capability supports replacement during system operation in redundant configurations, minimizing downtime for critical machinery monitoring systems.