EMERSON PR6423/11R-131 CON021 Proximity Sensor – PR6423 Series

EMERSON PR6423/11R-131 CON021 — Calibrated Eddy Current Proximity Sensor Assembly for Rotating Machinery Protection

The PR6423/11R-131 CON021 is a factory-calibrated eddy current proximity sensor and extension cable assembly manufactured by EMERSON (formerly Epro), designed for continuous non-contact measurement of shaft radial vibration, axial position displacement, and differential thermal expansion in critical rotating machinery. The assembly operates as a matched system: the PR6423/11R-131 probe and the CON021 extension cable are paired at the factory to maintain a defined output sensitivity of −8 V/mm (±0.2 V/mm) across the linear measurement range, eliminating field calibration errors that arise when mixing unmatched probe-cable combinations.

The /11R suffix designates an 11-meter integral cable with a right-angle connector exit geometry, suited for installations where radial cable routing clearance is constrained by bearing housings, seal glands, or structural steelwork. The -131 designator specifies the probe tip diameter and thread configuration, enabling direct thread-in replacement in existing PR6423-series probe holders without machining modifications. The CON021 extension cable adds a defined impedance segment between the probe and the signal conditioner (typically a PR9268 or PR6426 series unit), maintaining the total cable system within the calibrated impedance window required for accurate voltage-to-displacement conversion.

In turbomachinery protection architectures governed by API 670 (5th Edition), the sensor assembly feeds raw voltage signals to a dedicated monitor channel — such as the EMERSON 3500/40M or 3500/42M — where the signal is processed for 1× and 2× vibration vectors, DC gap voltage (shaft position), and alarm/trip relay actuation. The PR6423/11R-131 CON021 is fully compatible with this signal chain without requiring monitor sensitivity rescaling, provided the total cable system length remains within the conditioner’s specified range.

Real-time Stock & RFQ: [email protected] | WhatsApp: +86 18359268345

Technical Parameters

Hardware Logical Analysis

The eddy current proximity measurement principle relies on the interaction between a high-frequency oscillating magnetic field — generated by the probe coil driven at typically 1 MHz by the signal conditioner oscillator — and the conductive target surface. As the target approaches the probe face, eddy currents induced in the target surface load the oscillator circuit, reducing oscillation amplitude. The conditioner converts this amplitude change into a DC voltage proportional to the air gap distance, with the −8 V/mm sensitivity defining the transfer function.

The PR6423 probe coil is wound on a ferrite core and encapsulated in a ceramic-filled epoxy compound within the stainless steel housing. This construction achieves two objectives: it concentrates the magnetic flux field to a defined sensing zone (approximately 1× probe diameter in depth), minimizing sensitivity to adjacent conductive structures; and it provides thermal stability across the rated temperature range by matching the thermal expansion coefficients of the coil former, encapsulant, and housing.

The right-angle connector exit (/R) is not merely a mechanical convenience. In high-vibration environments, the cable exit geometry directly affects the fatigue life of the cable-to-probe junction. The right-angle design distributes bending stress over a longer radius at the exit point, reducing the peak strain amplitude at the solder joint under vibration loading — a critical consideration in installations where the probe itself is exposed to the vibration field it is measuring.

The CON021 extension cable maintains a defined coaxial impedance (typically 50 Ω) and capacitance per unit length. The total cable system capacitance — probe integral cable plus extension cable — must remain within the conditioner’s specified load range to preserve output linearity. EMERSON’s factory-matching process verifies this parameter for each probe-cable pair, issuing a calibration certificate that documents the measured sensitivity at the nominal gap and at the range endpoints. This traceability is a mandatory requirement under API 670 Section 5.3 for machinery protection sensor systems.

EMC performance is achieved through the coaxial cable shield, which provides continuous 360° coverage from the probe body to the conditioner input. The shield is grounded at the conditioner end only (single-point grounding), preventing ground loop currents that would appear as low-frequency noise on the DC output signal. In installations near variable-frequency drives or high-current bus bars, this single-point shield grounding is the primary defense against conducted interference that could mask real shaft dynamic events.

System Integration Benefits

• Direct API 670 compliance: The PR6423/11R-131 CON021 satisfies API 670 Section 5 sensor requirements for radial vibration and axial position channels without supplementary hardware, simplifying machinery protection system certification audits.
• Zero-recalibration replacement: The factory-matched sensitivity of −8 V/mm is identical across all PR6423 series assemblies of the same designation, allowing field replacement without adjusting monitor channel scale factors or alarm setpoints.
• Deterministic signal latency: The analog voltage output from the probe-conditioner chain introduces no digital processing delay. The monitor receives a continuous, real-time signal with a frequency response flat to at least 10 kHz, preserving high-frequency shaft dynamic content including blade-pass and gear-mesh frequencies.
• Diagnostic gap voltage monitoring: The DC component of the output voltage provides a continuous shaft centerline position measurement. Trending this value over time reveals bearing wear, thermal growth, and alignment shift — failure modes that vibration amplitude alone cannot detect.
• Multi-parameter measurement from a single probe: A single PR6423 channel can simultaneously provide radial vibration (AC component), shaft gap (DC component), and — when paired with a second orthogonal probe — shaft orbit data, reducing the total sensor count required per bearing plane.
• Compatibility with redundant monitor architectures: The analog output can be split to feed both a primary and a backup monitor channel using a passive signal splitter, supporting 1oo2 and 2oo3 voting logic configurations without additional active signal conditioning.
• Thermal stability across process extremes: The ceramic-encapsulated probe coil maintains sensitivity within the ±0.2 V/mm tolerance from −35 °C to +180 °C, covering steam turbine bearing housing temperatures encountered in both cold-start and full-load steady-state conditions.
• Seamless DCS integration: The 3500 series monitor rack outputs 4–20 mA analog signals and relay contacts that interface directly with DeltaV, Ovation, ABB 800xA, and Honeywell Experion DCS systems, enabling machinery protection data to appear in the plant-wide process historian without custom signal conditioning.
• Reduced installation commissioning time: The right-angle connector and 11-meter cable length accommodate the majority of standard turbomachinery bearing-to-junction-box distances, eliminating the need for field-fabricated cable extensions that introduce unverified impedance into the measurement chain.

Quality Assurance & Global Logistics

Every PR6423/11R-131 CON021 unit dispatched from our Xiamen facility undergoes a structured pre-shipment inspection protocol. Physical integrity of the probe body, cable sheath, and connector is verified under magnification. The EMERSON part marking, date code, and calibration label are cross-referenced against EMERSON’s published product identification documentation to confirm authenticity. Units sourced from authorized distribution channels are accompanied by original EMERSON packaging and documentation; surplus units from verified industrial decommissioning projects are inspected for cable continuity, connector contact resistance, and probe coil impedance before acceptance into stock.

Packaging for international shipment uses anti-static inner wrap, closed-cell polyethylene foam cushioning, and a moisture-barrier outer bag with desiccant. The outer carton is rated for air freight handling per IATA guidelines. Each shipment includes a packing list, commercial invoice with HS code 8543.70 (or applicable sub-heading), and a certificate of conformance. For customers requiring it, an EMERSON original datasheet and calibration record are included where available.

Logistics from Xiamen, China covers all major global destinations. Standard international express (DHL, FedEx, UPS) delivers to Europe and North America within 3–5 business days from dispatch. Air freight consolidation is available for larger orders requiring cost optimization. Sea freight LCL is available for bulk orders. Export documentation — including EUR.1 movement certificates, Form A GSP certificates, and CITES declarations where applicable — is prepared in-house by our logistics team, reducing customs clearance delays at destination ports.

All units carry a 12-month warranty from the date of shipment, covering manufacturing defects and specification non-conformance. Warranty claims are processed with a replacement-first policy to minimize customer downtime.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
© 2026 siemensplc.com. All rights reserved.