Emerson PR6424 Series 16mm Eddy-Current Contactless Sensor

Emerson PR6424 Series is a family of high-precision, 16mm eddy-current contactless sensors designed for non-contact measurement of displacement and vibration in critical rotating machinery. As part of Emerson's renowned EPRO product line, these sensors serve as the industry standard for monitoring radial and axial shaft dynamic displacement, position, eccentricity, and speed/key in steam turbines, gas turbines, hydro turbines, compressors, pumps, and fans .

Operating on the eddy current principle, the PR6424 series generates a low-power radio frequency field from the probe tip. When a conductive target enters this field, eddy currents are induced, altering the impedance of the probe coil. When paired with a compatible signal converter (such as CON011, CON021, CON031, or CON041), this impedance change is translated into a high-level DC voltage output directly proportional to the gap distance, enabling precise measurement of both static (position) and dynamic (vibration) parameters.

Key Technical Specifications

The PR6424 series is engineered to meet the stringent requirements of API 670 machinery protection standards .

Parameter Specification

Sensor Diameter 16 mm

Measurement Principle Non-contact eddy current

Sensitivity/Linearity 4 V/mm (101.6 mV/mil) ±1.5% max 

Static Measurement Range ±2.0 mm (0.079") 

Dynamic Measurement Range 0 to 1,000 µm (0 to 0.039") 

Nominal Air Gap (Center) Approximately 2.7 mm (0.11") 

Long-Term Drift < 0.3% 

Target Material Ferromagnetic steel (42 CrMo4 standard) 

Minimum Shaft Diameter ≥80 mm 

Maximum Surface Speed 2,500 m/s (98,425 ips) 

Operating Temperature (Sensor) -35°C to +180°C (-31°F to +356°F) 

Temperature Excursions <4 hours at 200°C (392°F) 

Pressure Resistance 10,000 hPa (145 psi) 

Shock/Vibration Resistance 5g @ 60Hz @ 25°C 

Protection Rating IP65 or IP67 (sensor) 

Construction Materials Stainless steel sleeve, PEEK sensor tip, PTFE-insulated cable 

Weight (Sensor with 1M Cable) 200 grams (7.05 oz) 

Thread Options M18x1.5 or 3/4"-16 UNF 

Certification Standards CE, ATEX, IEC-Ex, CSA, UL, API 670, DIN 45670, ISO 10817-1 

PR6424 Series System Components

A complete PR6424 measurement system consists of three essential components:

PR6424 Probe: The 16mm sensing element that mounts near the target shaft

Extension Cable: Connects the probe to the signal converter (various lengths available)

Signal Converter (CON011, CON021, CON031, or CON041): Conditions the signal and provides DC output proportional to gap

PR6424 Probe Models (Sensor Only)

Model Number Description / Configuration

PR6424/000-000 Basic 16mm eddy current probe, no integrated cable 

PR6424/000-010 Unarmored, 40mm sensor length, PTFE cable, M18x1.5 thread 

PR6424/000-030 Standard sensitivity configuration 

PR6424/000-030-CN Standard sensitivity, China region supply 

PR6424/000-100 Basic probe with standard cable configuration

PR6424/000-131 Unarmored, 90mm sensor length, PTFE cable, CON031 compatibility, M18x1.5 thread 

PR6424/000-140 Extended range configuration 

PR6424/002-030 Armored, 50mm sensor length, M18x1.5 thread 

PR6424/002-131 High-temperature configuration with CON031 compatibility

PR6424/006-030 2 meter integrated cable configuration

PR6424/006-111 Specific cable length configuration with CON031 compatibility 

PR6424/006-131 6mm probe configuration with CON041 compatibility 

PR6424/010-030 10mm probe configuration, standard sensitivity 

PR6424/010-040 10mm probe, armored, 60mm length, CON011 compatibility, 3/4"-16 UNF thread 

PR6424/010-100 10mm probe, total length 100mm, armored cable, PTFE-insulated 

PR6424/010-110 10mm probe with 110-series cable 

PR6424/010-131 10mm probe, extended range, armored, 90mm length, with adapter, M18x1.5 thread 

PR6424/011-140 11mm probe with high-temperature configuration 

PR6424/012-000 12mm probe configuration

PR6424/012-010 12mm probe with CON011 compatibility

PR6424/013-030 13mm probe configuration 

PR6424/014-120 14mm probe with 120-series cable 

Complete System Configurations (Probe + Converter)

Model Number Components Description

PR6424/000-000 CON021 PR6424/000-000 probe + CON021 converter Basic system with standard converter 

PR6424/000-030-CN CON021 PR6424/000-030-CN probe + CON021 converter Standard system with China region supply 

PR6424/000-100 CON021 PR6424/000-100 probe + CON021 converter Standard system with 100-series cable 

PR6424/000-140 CON021 PR6424/000-140 probe + CON021 converter Extended range configuration

PR6424/002-131 CON031 PR6424/002-131 probe + CON031 converter High-temperature system

PR6424/006-111 CON031 PR6424/006-111 probe + CON031 converter System with CON031 compatibility 

PR6424/006-131 CON041 PR6424/006-131 probe + CON041 converter Specialized high-temperature system 

PR6424/010-030 CON021 PR6424/010-030 probe + CON021 converter Standard 10mm system 

PR6424/010-040 CON011 PR6424/010-040 probe + CON011 converter 10mm system with CON011 converter 

PR6424/010-100 CON021 PR6424/010-100 probe + CON021 converter 10mm system with 100-series cable 

PR6424/010-110 CON021 PR6424/010-110 probe + CON021 converter 10mm system with 110-series cable 

PR6424/010-131 CON031 PR6424/010-131 probe + CON031 converter 10mm high-temperature system 

PR6424/014-120 CON021 PR6424/014-120 probe + CON021 converter 14mm system with 120-series cable 

Compatible Signal Converters

Converter Model Compatibility Key Specifications

CON011 PR6424 series Basic converter, standard output options 

CON021 PR6424 series Most common converter, -24V DC supply, IP20 

CON031 PR6424 series Enhanced performance, extended temperature range 

CON041 PR6424 series High-temperature applications, ruggedized 

Model Number Decoding Guide

Understanding the PR6424 model numbering system is essential for proper selection:

PR6424 - XXX - XXX - SUF

PR6424: Basic series designation (16mm eddy current sensor)

First XXX (Probe Code): Indicates mechanical configuration, cable type, and length

*000*: No integrated cable or unarmored configuration 

*002*: Short sensor, armored configuration 

*006*: 2 meter integrated cable 

*010*: 10mm probe length, armored configuration 

*011*: 11mm probe configuration 

*012*: 12mm probe configuration

*013*: 13mm probe configuration 

*014*: 14mm probe configuration 

Second XXX (Sensitivity/Length Code): Defines electrical characteristics and cable specifications

*000*: Basic configuration

*010*: CON011-compatible 

*030*: Standard sensitivity (4 V/mm) 

*040*: CON011-compatible, armored 

*100*: 100-series cable, standard length 

*110*: 110-series cable 

*111*: CON031-compatible 

*120*: 120-series cable 

*130*: Extended temperature range

*131*: High-temperature, CON031/CON041 compatible 

*140*: Extended range, high-temperature 

SUF (Suffix): Regional or special designation

*CON011/CON021/CON031/CON041*: Mated converter type

*-CN*: China region supply 

No suffix: Standard international version