Emerson PR6423/000-040 Eddy Current Sensor Precision Shaft Monitoring

Emerson PR6423/000-040 (manufactured under the EPRO brand) is a high-precision eddy current displacement sensor engineered to provide non-contact measurement of shaft vibration, position, and eccentricity in the most demanding industrial environments . As a fundamental component of Emerson's machinery protection systems, this 8mm probe delivers the accuracy, durability, and API 670 compliance required for steam turbines, gas turbines, compressors, pumps, and gearboxes worldwide .

What is the Emerson PR6423/000-040?

The PR6423/000-040 is an inductive eddy current sensor designed for permanent installation on critical rotating machinery . Unlike contact-based measurement devices, this sensor utilizes advanced eddy current technology to detect the position of a shaft relative to the probe tip without any physical contact, ensuring wear-free operation and long-term stability .

The "000-040" designation in the model number indicates a specific configuration: a standard sensor head with a 40-meter (131-foot) integrated cable . This extended cable length makes the PR6423/000-040 particularly suitable for installations where the monitoring system is located at a considerable distance from the measurement point, such as in large power plants or petrochemical facilities .

Key Technical Specifications

The Emerson PR6423/000-040 is built to exacting standards, with specifications verified across multiple industrial sources :

Parameter Specification

Manufacturer Emerson / EPRO

Model Number PR6423/000-040

Product Type Eddy Current Displacement Sensor

Probe Tip Diameter 8 mm

Cable Length 40 m (integral, non-removable)

Linear Measurement Range 2 mm (80 mils)

Initial Air Gap 0.5 mm (20 mils)

Incremental Scale Factor (ISF) 8 V/mm ±5% (0–45°C) 

Deviation from Straight Line (DSL) ±0.025 mm (±1 mil) 

Frequency Response DC to 10 kHz (static and dynamic measurements) 

Minimum Shaft Diameter 25 mm (0.79 in) 

Target Material Ferromagnetic steel (42CrMo4 / AISI 4140 standard) 

Operating Temperature (Sensor Tip) -35°C to +200°C (-31°F to +392°F) 

Operating Temperature (Cable) -35°C to +150°C (-31°F to +302°F) 

Protection Class IP66 (IEC 60529) 

Housing Material Stainless steel 

Tip Material PEEK (Polyether ether ketone) 

Weight (with 1m cable) Approx. 100 g (3.53 oz) 

Compliance API 670 

What Does the PR6423/000-040 Measure?

This versatile sensor is capable of monitoring multiple critical parameters :

Radial Vibration: Dynamic motion of the shaft relative to the machine casing

Axial Position (Thrust): The position of the rotor along the shaft axis, critical for thrust bearing monitoring

Shaft Eccentricity: Slow-roll bow or bend in the rotor during startup

Speed and Phase Reference: When used with keyphasor applications

The PR6423 series includes several variants for different applications :

Model Key Difference

PR6423/000-040 Standard 8mm probe, 40m cable (this model)

PR6423/000-030 Standard 8mm probe, 30m cable

PR6423/002-040 High-temperature version, 40m cable

PR6423/003-131 Different cable/connector configuration

PR6423/010-040 Extended measurement range variant

Emerson PR6423/000-040 Eddy Current Sensor represents the gold standard in non-contact shaft measurement technology. With its 8mm probe tip, 40-meter integrated cable, and rugged IP66 construction, it delivers the precision and reliability required for API 670-compliant machinery protection systems.