EPRO PR9350 Series Modules

Technical Dossier

Product Details And Specifications

EPRO PR9350 Series: Comprehensive Module Range and Technical Overview

The EPRO PR9350 series is a family of inductive displacement sensors (variable differential transformers / eddy-current proximity transducers) manufactured by EPRO GmbH, a subsidiary of Emerson Automation Solutions. These sensors are deployed globally in heavy industrial environments including petrochemical refineries, nuclear power stations, offshore platforms, and rotating machinery protection systems. The PR9350 series functions as the primary sensing element in shaft displacement and position measurement chains, typically paired with EPRO signal conditioning modules (PR6423, PR6424, PR9376 series) and Bently Nevada 3500-series monitoring racks. Their robust construction — stainless steel housing, hermetically sealed coil assembly, and wide temperature tolerance — makes them the reference standard for API 670-compliant machinery protection installations.

The Evolution of PR9350 Architecture

The PR9350 series traces its lineage to EPRO's early inductive sensor platforms developed in the 1980s for turbomachinery OEM integration. The original PR9350/00 and PR9350/01 variants established the M8 threaded body form factor and the 5 mm nominal sensing gap standard that remains consistent across the entire product family. As industrial DCS platforms migrated from analog 4–20 mA loops to digital fieldbus architectures (FOUNDATION Fieldbus, PROFIBUS PA), EPRO introduced variants with extended cable assemblies and revised connector standards to maintain backward compatibility with legacy Bently Nevada 7200 and 3300 series proximitor systems.

The /S1 and /S2 suffix designations denote cable length and connector configuration variants — not functional changes to the sensing element. The /02 infix identifies the second-generation coil geometry optimized for reduced temperature drift. As of 2024, the PR9350 series is classified as a mature/sustaining product line; EPRO continues to supply replacement units but active development has shifted to the PR9376 eddy-current series with integrated signal conditioning. For installations locked to PR9350-compatible signal conditioners, DriveKNMS maintains long-term supply of both new and refurbished units.

PR9350 Full Catalog & Functionalities (SKU List)

The following SKUs represent the documented PR9350 series range. Each unit is a passive inductive displacement sensor; functional differences relate to cable length, connector type, sensing range, and housing variant.

PR9350/00: Standard M8 inductive sensor, 5 mm gap, bare cable termination, 1 m cable.
PR9350/01: Standard M8 inductive sensor, 5 mm gap, 3 m integral cable, bare end.
PR9350/01-S1: M8 body, 3 m cable, MIL-C-5015 style connector, single-ended.
PR9350/02: Second-generation coil, reduced thermal drift, 5 mm gap, 1 m cable.
PR9350/02-S1: Second-gen coil, 1 m cable, standard EPRO bayonet connector.
PR9350/02-S2: Second-gen coil, 3 m cable, EPRO bayonet connector — primary stocking SKU.
PR9350/02-S3: Second-gen coil, 5 m cable, EPRO bayonet connector, extended reach.
PR9350/02-S4: Second-gen coil, 9 m cable, EPRO bayonet connector, long-run installations.
PR9350/03: High-temperature variant, rated to +180 °C, 5 mm gap, 1 m cable.
PR9350/03-S1: High-temp, 3 m cable, standard connector, steam turbine applications.
PR9350/03-S2: High-temp, 5 m cable, EPRO bayonet, hot-section proximity installations.
PR9350/04: Extended range variant, 8 mm nominal gap, M12 body, 1 m cable.
PR9350/04-S1: Extended range, 3 m cable, M12 body, compressor shaft monitoring.
PR9350/05: Intrinsically safe (ATEX Zone 0) certified variant, 5 mm gap, 1 m cable.
PR9350/05-S1: ATEX Zone 0, 3 m cable, Ex ia IIC T6 rating, offshore/hazardous area.
PR9350/05-S2: ATEX Zone 0, 5 m cable, Ex ia IIC T6, petrochemical plant installations.
PR9350/06: Cryogenic service variant, rated to −60 °C, LNG compressor applications.
PR9350/07: Submersible variant, IP68 rated, subsea pump shaft monitoring.

Sourcing Hard-to-Find & Obsolete PR9350 Parts

DriveKNMS maintains a dedicated inventory program for the EPRO PR9350 series, with particular focus on variants that have been discontinued or are subject to extended lead times from the OEM channel. For installations where the PR9350 signal conditioner chain (PR6423/PR6424 proximitor) cannot be replaced without a full system re-engineering project, sourcing a like-for-like PR9350 replacement is the lowest-risk, lowest-cost maintenance path.

DriveKNMS sources PR9350 units through: (1) direct OEM surplus channels, (2) decommissioned plant asset recovery, and (3) certified refurbishment of pulled units. All refurbished sensors undergo full coil resistance verification, insulation resistance testing, and dimensional inspection before dispatch. Customers operating Bently Nevada 3500/40M or 3500/42M monitor cards paired with PR9350 sensors can request a compatibility verification report prior to purchase. Lead time for in-stock units is typically 3–7 business days worldwide.

Quality Control for the PR9350 Range

The PR9350 sensor presents specific quality verification challenges due to its passive inductive construction and the precision tolerances required for API 670 compliance. DriveKNMS applies the following test protocol to all PR9350 units processed through its facility:

Coil Resistance Measurement: DC resistance of primary and secondary coils measured against OEM specification (typically 40–60 Ω primary). Deviation >5% triggers rejection.
Insulation Resistance: 500 VDC megohm test between coil windings and housing. Minimum acceptance: 100 MΩ.
Dimensional Inspection: Thread form (M8×1.0 or M12×1.0), body length, and tip geometry verified against EPRO mechanical drawings.
Cable Integrity: Full continuity and shield isolation test across the integral cable assembly. Connector pin-out verified against EPRO wiring standard.
Functional Gap Test: Sensor installed in calibrated fixture; output impedance measured at 5 mm nominal gap using a Bently Nevada 3500-series proximitor as reference instrument. Output must fall within ±2% of OEM nominal.
Temperature Soak: High-temperature variants (PR9350/03 series) subjected to 2-hour soak at rated maximum temperature prior to final electrical verification.