Emerson PR6423/000-120 Eddy Current Sensor Precision Shaft Monitoring

Emerson PR6423/000-120 (formerly EPRO) is a precision-engineered eddy current displacement sensor designed to provide non-contact, wear-free measurement of shaft vibration, axial position, and eccentricity in the most demanding industrial environments .

What is the Emerson PR6423/000-120?

The PR6423/000-120 is an 8 mm eddy current probe from Emerson's AMS / EPRO PR6423 series, specifically designed for continuous monitoring of critical rotating machinery including steam turbines, gas turbines, compressors, gearboxes, pumps, and fans . What sets this particular model apart is its integrated 20-meter cable, making it the ideal solution for installations where the monitoring system is located at a significant distance from the measurement point .

Using proven eddy current technology, this sensor generates a high-frequency magnetic field from its tip. As a ferromagnetic target (such as a rotating shaft) moves within this field, eddy currents are induced, and the sensor detects the impedance change—converting physical displacement into a precise, linear analog voltage output .

Key Technical Specifications

The PR6423/000-120 is engineered to meet the stringent requirements of the API 670 standard for machinery protection systems .

Specification Detail

Manufacturer Emerson / EPRO 

Model Number PR6423/000-120 

Product Type Eddy Current Displacement Sensor 

Probe Tip Diameter 8 mm 

Cable Length 20 m (integrated) 

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 Best Fit Line (DSL) ±0.025 mm 

Minimum Shaft Diameter 25 mm (0.79 in) 

Target Material Ferromagnetic steel (42CrMo4 / AISI 4140) 

Frequency Response Up to 10 kHz (suitable for high-speed dynamic measurements) 

Output Signal Analog voltage (requires signal conditioner like CON021) 

Operating Temperature -40 °C to +125 °C (standard) 

Protection Class IP66 (IEC 60529) - dust-tight and protected against powerful water jets 

Housing Material Stainless steel 

Weight 0.3–0.4 kg 

Compliance API 670 

The PR6423/000-120 is typically deployed as part of a complete measurement chain:

Sensor: PR6423/000-120 (eddy current probe with 20m cable)

Signal Conditioner: CON021 or CON041 (converts raw signal to standardized outputs) 

Monitor: AMS 6500, MMS6000, or VM600 series monitors (provides protection, alarms, and diagnostics) 

This integrated approach ensures that raw shaft displacement data is transformed into actionable intelligence for predictive maintenance and machine protection.

The Emerson PR6423/000-120 eddy current sensor combines an 8 mm probe with an integrated 20-meter cable to deliver reliable, high-accuracy shaft vibration and position data in the most challenging industrial environments . Its IP66 rating, wide temperature range, and API 670 compliance ensure that your most valuable rotating assets remain protected around the clock.