EPRO PR6426 Eddy Current Sensor System: PR6426/010-140 CON021/912-160

Technical Dossier

Product Details And Specifications

EPRO PR6426 Series: Comprehensive Module Range and Technical Overview

The EPRO PR6426 series is a family of eddy current displacement and vibration sensors manufactured by EPRO GmbH (now part of Emerson Automation Solutions). These sensors are deployed across global heavy industry — including petrochemical refineries, nuclear power stations, offshore platforms, and rotating machinery installations — as the primary non-contact measurement solution for shaft displacement, radial vibration, axial position, and differential expansion monitoring. The PR6426 series is fully compatible with the EPRO CON021 signal conditioning system and integrates directly into Bently Nevada 3500 series monitoring racks via standard 4–20 mA or voltage output interfaces. Its installed base spans decades of continuous operation in critical machinery protection systems worldwide.

The Evolution of PR6426 Architecture

The PR6426 series was introduced by EPRO as a standardized eddy current probe system designed to replace earlier discrete sensor assemblies with a modular probe-plus-conditioner architecture. Early variants used fixed-length integral cables and were calibrated exclusively for use with EPRO's own signal conditioners. As industrial standards evolved, EPRO introduced extension cable compatibility (CON011/CON021 conditioner pairing), allowing probe-to-conditioner distances of up to 9 meters with standardized 5-meter and 9-meter cable sets.

The transition from CON011 to CON021 conditioners marked a significant architectural shift: CON021 units introduced improved EMI shielding, wider temperature operating ranges (−40°C to +85°C), and compatibility with both API 670 and IEC 61511 functional safety frameworks. The PR6426 probe body itself remained dimensionally consistent across generations, ensuring backward mechanical compatibility with existing installation hardware. Following Emerson's acquisition of EPRO, the series entered a mature/end-of-active-production phase; however, the installed base remains extensive, and long-term maintenance support — including tested surplus and refurbished units — remains commercially critical for operators committed to multi-decade asset lifecycles.

PR6426 Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly sourced models within the EPRO PR6426 eddy current sensor and CON021 conditioner ecosystem. Each entry reflects a distinct configuration of probe gap range, cable length, or conditioner channel count.

PR6426/000-000: Standard eddy current probe, 5mm range, no extension cable, bare lead termination.
PR6426/000-010: Standard probe, 5mm range, 0.5m integral cable, standard connector.
PR6426/005-000: Probe with 5mm measurement range, metric thread body, 1m cable.
PR6426/005-010: 5mm range probe, 1m cable, EPRO standard connector, stainless housing.
PR6426/010-100: 10mm range probe, 5m extension cable compatible, standard termination.
PR6426/010-110: 10mm range probe, 5m cable set, CON021 conditioner matched pair.
PR6426/010-130: 10mm range probe, 9m cable configuration, stainless steel body.
PR6426/010-140: 10mm range probe, 9m extension cable, CON021/912-160 conditioner matched — this listing's primary probe SKU.
PR6426/020-000: 20mm range probe, integral cable, used for large-shaft axial position measurement.
PR6426/020-010: 20mm range probe, 0.5m cable, standard connector, high-temperature variant.
PR6426/020-100: 20mm range probe, 5m extension cable, CON021 compatible.
PR6426/020-140: 20mm range probe, 9m cable, CON021/912-160 conditioner matched pair.
CON021/912-100: Single-channel signal conditioner, 5m cable system, 4–20 mA output, DIN rail mount.
CON021/912-130: Single-channel conditioner, 9m cable system, voltage output, panel mount.
CON021/912-160: Single-channel conditioner, 9m cable system, dual output (4–20 mA + voltage), API 670 compliant — this listing's primary conditioner SKU.
CON021/912-200: Dual-channel conditioner module, 5m cable system, rack-mount format.
CON021/912-260: Dual-channel conditioner, 9m cable, dual output, for redundant measurement loops.
CON041/916-160: Four-channel conditioner, compatible with PR6426 probes, used in high-density monitoring panels.

Sourcing Hard-to-Find & Obsolete PR6426 Parts

The PR6426 series has entered the mature phase of its product lifecycle. EPRO/Emerson no longer actively promotes new installations of this series for greenfield projects; however, the global installed base — particularly in refineries and power generation facilities commissioned between 1990 and 2015 — continues to require like-for-like replacement units to avoid costly system-wide upgrades.

Quality Control for the PR6426 Range

The PR6426 probe and CON021 conditioner system requires specialized test procedures due to the sensitivity of the eddy current measurement circuit to cable impedance, probe gap calibration, and conditioner gain linearity. DriveKNMS applies the following verification protocol to all PR6426 units prior to shipment:

Each probe is tested for coil resistance and inductance against EPRO factory specification tolerances. Extension cable assemblies are verified for continuity, insulation resistance (>100 MΩ at 500 VDC), and characteristic impedance. CON021 conditioners undergo full functional testing across the specified measurement range (0–10 mm or 0–20 mm depending on variant), with output linearity verified at five calibration points. Dual-output conditioners (CON021/912-160 and CON021/912-260) are tested on both the 4–20 mA and voltage output channels simultaneously. All units are burned in for a minimum of 4 hours at operating temperature before final inspection. Test records are retained for a minimum of 5 years and are available to customers upon request.