Emerson PR6423/000-031 Eddy Current Sensor Precision Shaft Monitoring

Emerson PR6423/000-031 is a high-performance, 8 mm eddy current displacement sensor designed for non-contact measurement of shaft vibration, axial position, and eccentricity in critical rotating machinery. As part of the renowned EPRO series by Emerson, this sensor represents the gold standard for condition monitoring in steam turbines, gas turbines, compressors, and pumps, complying fully with the stringent API 670 standard for machinery protection systems .

What is the Emerson PR6423/000-031?

The PR6423/000-031 is an eddy current displacement sensor that utilizes advanced electromagnetic technology to detect the precise position of a rotating shaft without physical contact. The "000-031" suffix typically indicates the standard 8 mm probe tip with a specific configuration (often including an integrated 31-meter cable when paired with a CON041 converter, or an 8-meter cable for standalone use) .

This sensor operates by generating a high-frequency magnetic field from the probe tip. When a conductive target (the rotating shaft) approaches this field, eddy currents are induced, altering the impedance of the sensing coil. This change is converted into a linear voltage signal, providing real-time data on the shaft's position and dynamic motion . Designed for the most demanding environments, the PR6423/000-031 features a rugged stainless steel housing and an IP66 protection rating, ensuring reliable operation in the presence of oil, moisture, and contaminants .

Key Technical Specifications (Specs)

The Emerson PR6423/000-031 is engineered for exceptional linearity, stability, and environmental endurance.

Manufacturer: Emerson (EPRO Series)

Model Number: PR6423/000-031

Sensor Type: Non-contact Eddy Current Displacement Sensor

Probe Tip Diameter: 8 mm

Linear Measurement Range: 2 mm (80 mils) 

Initial Air Gap (Nominal): 0.5 mm (20 mils) 

Incremental Scale Factor (Sensitivity): 8 V/mm (203.2 mV/mil) ±5% @ 0-45°C 

Deviation from Best Fit Line (Linearity Error): ±0.025 mm (±1 mil) @ 0-45°C 

Frequency Response: Up to 10 kHz 

Minimum Shaft Diameter: > 25 mm (0.98 in) 

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

Operating Temperature (Sensor with 1m cable): -35°C to +200°C (-31°F to +392°F) 

Cable & Connector Temperature: -35°C to +150°C 

Protection Class: IP66 (IEC 60529) 

Housing Material: Stainless Steel 

Probe Tip Material: PEEK (Polyether ether ketone) 

Cable Length Options: Available with integrated cables, commonly 8 meters (for standalone use) or paired with a CON041 converter featuring a 31-meter cable for remote mounting .

Connector: Often terminated with a self-locking LEMO plug for secure connection to signal converters .

Weight (approx.): ~100 grams (sensor with 1m cable) to 0.4 kg (with converter) .

Compliance: API 670, CE, ATEX, IECEx, CSA (when used with appropriate barriers) .

How the PR6423/000-031 Works

The PR6423/000-031 is typically used in conjunction with a signal converter, such as the CON021 or CON041 . The sensor connects to the shaft via a precise air gap. As the shaft rotates, microscopic changes in position (vibration, thrust, or eccentricity) alter the gap distance. The sensor detects these changes, and the signal converter processes the raw signal, converting it into standardized outputs like 0-10 V DC or 4-20 mA, which can be read by monitoring systems such as the Emerson CSI 6500 or AMS 6500 machinery protection systems . This allows for seamless integration into plant DCS, PLC, or safety systems.

Emerson PR6423/000-031 Eddy Current Sensor offers an unmatched combination of precision, durability, and API 670 compliance. Its ability to provide accurate, non-contact measurements in the harshest industrial environments makes it an indispensable tool for predictive maintenance and machinery protection.