Emerson PR6424/000-000 16mm Eddy-Current Contactless Sensor

Emerson PR6424/000-000 CON021 is a high-precision, non-contact eddy current sensor system designed for critical machinery protection and condition monitoring applications. As part of Emerson's renowned EPRO product line, this 16mm sensor family represents the gold standard for measuring radial and axial shaft displacement, vibration, eccentricity, and rotational speed on large rotating equipment .

Engineered specifically for API 670-compliant machinery protection systems, the PR6424 series excels in demanding environments such as steam turbines, gas turbines, hydroelectric generators, centrifugal compressors, large pumps, and industrial fans .

How Eddy Current Technology Works

The PR6424/000-000 operates on fundamental physical principles: when a high-frequency alternating current passes through the sensor tip, it generates a magnetic field. When a conductive target (the rotating shaft) enters this field, eddy currents are induced, altering the impedance of the probe coil . The CON021 signal converter detects this impedance change and outputs a DC voltage directly proportional to the gap distance.

This non-contact measurement method provides:

Wear-free operation with unlimited mechanical life

Sub-micron resolution for detecting minute changes

DC response capturing both static position and dynamic vibration

Key Technical Specifications

Sensor Specifications (PR6424/000-000)

Parameter Value

Sensor Type Eddy Current (Non-contact) 

Sensor Head Diameter 16 mm 

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

Air Gap (Center) Approx. 2.7 mm (0.11") Nominal 

Static Measurement Range ±2.0 mm (0.079") 

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

Minimum Shaft Diameter ≥80 mm 

Target Material Ferromagnetic Steel (42 Cr Mo4 Standard) 

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

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

Temperature Drift <4%/100°K (API 670 Compliant) 

Pressure Resistance 10,000 hPa (145 psi) 

Shock and Vibration 5g @ 60 Hz @ 25°C (77°F) 

Material Stainless Steel Sleeve, PTFE Cable 

Weight (Sensor & 1M Cable) ~200 grams (7.05 oz) 

Protection Class IP66 (with appropriate connector) 

CON021 Signal Converter Specifications

Parameter Value

Frequency Range (-3 dB) 0 to 20,000 Hz 

Rise Time <15 μs 

Operating Temperature -30°C to +100°C (-22°F to +212°F) 

Supply Voltage Range -23V to -32V (Output -4V to -20V), -21V to -32V (Output -2V to -18V) 

Protection Class IP20 

Housing Material LMgSi 0.5 F22 

Weight ~120 grams (4.24 oz) 

Mounting 4 Screws M5x20 

Connections Self-locking Lemo Plug (sensor), Screw Terminal (supply/output)