EPRO PR6423/002-000+CON021 Eddy Current Sensor – PR6423 Proximitor Series

EPRO PR6423/002-000+CON021 — Non-Contact Shaft Displacement Sensor for API 670 Machinery Protection

The PR6423/002-000+CON021 is a complete eddy current proximity measurement assembly from EPRO GmbH, comprising the PR6423/002-000 probe body and the CON021 matched-impedance extension cable. This system is designed for continuous, non-contact measurement of radial shaft vibration and axial position displacement on rotating machinery operating under API 670 protection requirements. The assembly delivers a calibrated output of −24 VDC nominal, compatible with the full range of EPRO MMS6000-series monitors and Bently Nevada 3500-series racks when used with appropriate signal conditioning.

Within the PR6423 product family, the /002-000 suffix designates a 2-metre probe cable configuration — the standard deployment length for most turbine bearing housings and compressor pedestals where the proximitor driver is mounted within the same enclosure or junction box. The CON021 extension cable provides an additional conditioned signal path, maintaining the −24 V bias supply and output impedance characteristics across the full cable run without introducing nonlinearity at the monitor input. This matched-system approach eliminates the calibration errors that arise when mixing probe and extension cables from different manufacturers or series.

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Technical Parameters

Hardware Logical Analysis

The PR6423 probe operates on the Lenz’s law induction principle: a high-frequency oscillator (typically 1 MHz carrier) drives a coil wound within the probe tip. When a conductive target enters the electromagnetic field, eddy currents are induced on the target surface, loading the coil and reducing its Q-factor. The driver circuit converts this impedance change into a DC voltage proportional to the gap distance. The PR6423/002-000 probe is factory-calibrated against a standard AISI 4140 steel target; sensitivity is trimmed to 7.87 V/mm ± 3% across the specified linear range.

EMC Design: The probe cable uses a triaxial shielding architecture — inner conductor, inner shield (driven at the same potential as the signal to eliminate capacitive loading), and outer shield connected to chassis ground. This driven-shield (guard) technique suppresses common-mode interference from variable-frequency drives, high-voltage bus bars, and RF sources common in turbine halls, maintaining signal integrity at frequencies up to 10 kHz without external filtering.

CON021 Extension Logic: The CON021 is not a passive cable. It contains a precision impedance-matching network that compensates for the distributed capacitance of the extension run. Without this compensation, cable capacitance would attenuate high-frequency vibration components and shift the probe’s effective sensitivity. The CON021 maintains the system’s calibrated sensitivity across the full extension length, ensuring that the monitor receives a signal indistinguishable from a direct short-cable connection. This is critical for accurate 1× and 2× running-speed vibration amplitude measurements used in API 670 alarm and trip logic.

Intrinsic Safety Barrier Compatibility: The PR6423 series is designed to interface with Zener barrier or galvanic isolator circuits for Zone 0/1 installations. The probe’s inductance and capacitance parameters are within the entity parameters required by standard IS barriers (e.g., MTL 764, P&F KFD2-series), allowing direct ATEX-certified installation without additional entity calculations in most standard configurations.

System Integration Benefits

• Direct Monitor Compatibility: The −24 VDC bias and 7.87 V/mm sensitivity are the EPRO/Bently Nevada industry standard. The PR6423/002-000+CON021 connects directly to EPRO MMS6110, MMS6120, MMS6210, and Bently Nevada 3500/42M monitors without recalibration or sensitivity adjustment at the monitor card.
• Deterministic Frequency Response: The DC-to-10 kHz flat response covers all sub-synchronous, synchronous, and super-synchronous vibration components relevant to API 670 monitoring, including oil whirl (typically 0.43–0.48×), 1× unbalance, 2× misalignment, and blade-pass frequencies on most industrial turbomachinery.
• Zero Mechanical Wear: Non-contact measurement eliminates probe degradation from shaft contact. Mean time between replacement is governed by environmental factors (temperature cycling, chemical exposure) rather than mechanical wear, supporting multi-year maintenance intervals in clean installations.
• Axial Position Measurement Capability: The same probe assembly can be configured for thrust position monitoring by mounting perpendicular to the shaft end face. The linear range of 0.25–2.25 mm accommodates typical thrust collar travel limits specified in API 670 Table 1.
• Diagnostic Transparency: The analog output voltage is directly readable with a standard DVM, allowing field engineers to verify gap distance and probe health without a dedicated monitor. A reading of −10.5 V at the CON021 output indicates a 1.33 mm gap — a straightforward field check that requires no special tooling.
• Redundant System Architecture Support: The PR6423 probe’s compact M14 thread body allows dual-probe installation in a single bearing housing using standard EPRO dual-probe holders, supporting 2-of-2 or 2-of-3 voting logic in SIL-rated protection systems without enlarging the bearing housing bore.
• Hazardous Area Deployment: ATEX II 1G certification permits installation in Zone 0 gas atmospheres — the most demanding classification — covering LNG terminals, hydrogen compressor stations, and offshore platform machinery spaces where other sensor technologies require additional protective enclosures.
• Standardized Spare Parts Management: The PR6423/002-000+CON021 is a globally stocked assembly. Its part number is recognized by SAP PM, Maximo, and Oracle EAM systems at major utilities and petrochemical operators, simplifying procurement and inventory management for MRO teams.

Quality Assurance & Global Logistics

Every PR6423/002-000+CON021 unit supplied by siemensplc.com is sourced from verified EPRO-authorized distribution channels. Each assembly undergoes a structured pre-shipment inspection protocol:

• Authenticity Verification: Label typography, serial number format, and connector finish are cross-referenced against EPRO factory documentation. Counterfeit detection is performed on every unit, not on a sampling basis.
• Electrical Functional Test: Probe coil impedance is measured at 1 kHz using a precision LCR meter. Values outside the factory-specified range (typically 15–25 Ω coil resistance, 50–80 µH inductance for the PR6423 tip geometry) result in rejection.
• Cable Continuity and Insulation: CON021 extension cable is tested for conductor continuity, shield integrity, and insulation resistance (>100 MΩ at 500 VDC) prior to packaging.
• Packaging: Assemblies are packed in anti-static foam-lined cases with moisture-barrier desiccant. Probe tips are protected with thread caps and tip guards. Documentation includes inspection record, certificate of conformance, and original EPRO datasheet.

Shipment originates from Xiamen, China. Standard export carriers are DHL Express, FedEx International Priority, and UPS Worldwide Express. Typical transit times: Southeast Asia 2–3 days; Europe 3–5 days; North America 4–6 days; Middle East 3–5 days. Full export documentation — commercial invoice, packing list, certificate of origin — is provided for all international orders. HS Code 9031.80 applies to this product category for customs classification purposes. A 12-month warranty covers manufacturing defects and functional failure under normal operating conditions.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
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