Bently Nevada 125808-01 Proximitor External Termination Block: Flexible Field Wiring Interface for 3500 Machinery Protection Systems
Overview
The Bently Nevada™ 125808-01 Proximitor External Termination Block (ET Block) is a four-channel signal interface designed to provide reliable external termination for proximity probe transducer signals within the 3500 Series machinery protection system. Featuring Euro Style connectors, this ET Block serves as the physical junction point where field wiring from proximity probes lands and connects to the 3500/40M Proximitor Monitor via a dedicated interconnect cable.
Description
The 125808-01 Proximitor ET Block enables flexible cabinet layout by moving transducer wiring termination away from the back of the 3500 rack to a separate, accessible location. This architecture simplifies field wiring management, facilitates loop checks, and reduces maintenance time in high-density installations.
When ordering a 3500/40M Proximitor Monitor with an external termination I/O module, the ET Block and interconnect cable must be ordered separately. The 125808-01 is specifically designed for use with the 3500/40M Proximitor I/O Module with External Terminations. Field wiring from proximity probes terminates at the ET Block, and a 129525 Transducer Signal to External Termination Block Cable connects the ET Block to the rear I/O module in the 3500 rack.
Key Features and Benefits
Four-Channel Capacity: The 125808-01 provides termination for up to four proximity probe channels, enabling efficient wiring management for multi-channel machinery protection applications.
Euro Style Connectors: Equipped with Euro Style connectors for secure, reliable field wiring termination. For applications requiring terminal strip connectors, the alternative 128015-01 Proximitor ET Block is available.
Flexible Cabinet Layout: Enables field termination to be located separately from the 3500 rack, simplifying cable routing and improving accessibility for commissioning and maintenance activities.
Seamless 3500 System Integration: Designed specifically for use with the 3500/40M Proximitor Monitor and its external termination I/O module, ensuring proper signal integrity and system compatibility.
Compatible with Multiple Monitor Modules: Suitable for use with the 3500/40M Proximitor Monitor and other 3500 Series modules that support external termination configurations.
System Architecture
In a typical external termination configuration using the 125808-01 ET Block, the signal path is as follows:
Field Sensor: Proximity probe installed on the machine
Field Wiring: Shielded transducer cable routed to the ET Block location
125808-01 ET Block: Physical termination point where field wiring lands
Interconnect Cable (129525): Connects the ET Block to the 3500 rack I/O module
3500/40M I/O Module: Rear module that interfaces with the Proximitor Monitor
3500/40M Monitor: Front module that processes signals for protection and monitoring
Technical Specifications
Parameter Specification
Model 125808-01 Proximitor ET Block
Product Type: External Termination Block
Connection Style: Euro Style Connectors
Channel Capacity: 4 channels
Compatible Monitor 3500/40M Proximitor Monitor
Compatible I/O Module 3500/40M I/O Module with External Terminations
Interconnect Cable 129525 Transducer Signal to External Termination Block Cable
Mounting Panel or rack-mountable
Weight: Approximately 0.91 kg
Applications
The 125808-01 Proximitor ET Block is used across a wide range of machinery protection applications in the 3500 Series system:
Turbomachinery Protection: Steam turbines, gas turbines, and compressor trains requiring external termination for proximity probe vibration and position measurements
Rotating Equipment Monitoring: Pumps, motors, fans, and gearboxes in oil & gas, power generation, and petrochemical facilities
Retrofit and Upgrade Projects: Enables flexible integration with existing 3500 Series monitoring infrastructure where external termination is preferred
Remote Field Termination: Suitable for installations where field wiring is terminated at a location separate from the 3500 rack
Installation and Configuration Notes
External vs. Internal Termination: External termination blocks cannot be used with internal termination I/O modules. The 3500/40M Proximitor Monitor must be ordered with a compatible external termination I/O module when using the 125808-01 ET Block.
Separate Ordering: When ordering I/O modules with external terminations, the ET Block and interconnect cable must be ordered separately for each I/O module
Cable Connection: Use the 129525 Transducer Signal to External Termination Block Cable to connect the ET Block to the 3500 rack I/O module. Available cable lengths include 1.5 m, 2.1 m, 3.0 m, 7.6 m, 15.2 m, and 30.5 m
Shield Termination: Properly terminate transducer cable shields to ground to prevent electromagnetic interference
Frequently Asked Questions
What is the primary function of the 125808-01 Proximitor ET Block?
The 125808-01 serves as the physical termination point for proximity probe field wiring, providing a clean interface between field-mounted sensors and the 3500/40M Proximitor Monitor via a dedicated interconnect cable.
Which monitor module is this ET Block compatible with?
The 125808-01 is specifically designed for use with the 3500/40M Proximitor Monitor and its external termination I/O module.
Does the ET Block include the interconnect cable?
No. The ET Block and the 129525 interconnect cable must be ordered separately when configuring an external termination installation.
Is a terminal strip version available?
Yes. The 128015-01 Proximitor ET Block provides the same functionality with Terminal Strip connectors instead of Euro Style connectors.
Can I use this ET Block with internal termination I/O modules?
No. External termination blocks cannot be used with internal termination I/O modules.
Related Products
128015-01: Proximitor ET Block with Terminal Strip Connectors
129525: Transducer Signal to External Termination Block Cable
3500/40M: Proximitor Monitor (main module)
128240-01: Prox/Seismic I/O Module with External Terminations
125808-01
128015-01
132242-01
132234-01
129525-0010-01
129525-0025-01
129525-0050-01
129525-0100-01
129525-0010-02
129525-0025-02
129525-0050-02
129525-0100-02
140734-01
125680-01
126615-01
135489-04
149716-01
143488-01
