Description
Emerson EPRO PR6424/006-030 | 16 mm Eddy Current Sensor
Architect’s Product Breakdown
The Emerson EPRO PR6424/006-030 + CON021 is a non-contact shaft measurement assembly for rotating machinery protection and condition monitoring. The 16 mm PR6424 sensor measures the distance between its sensing face and a ferromagnetic steel target. The CON021 converter converts the probe signal into an analog voltage for a compatible machinery monitoring system. Typical applications include steam turbines, gas turbines, hydro turbines, compressors, pumps, and fans where shaft vibration and displacement measurements are used to assess mechanical condition.
The PR6424/006-030 specification identifies a nominal sensitivity of 4 V/mm (101.6 mV/mil), a nominal center air gap of approximately 2.7 mm, and a static measurement range of ±2.0 mm. The sensor is designed for a ferromagnetic steel target, with 42CrMo4 as the standard reference material. The CON021 converter has a specified frequency response of 0–20 kHz at −3 dB and a rise time below 15 µs. These figures describe the measurement hardware; actual system performance also depends on cable condition, target geometry, installation, and the receiving monitor.
For a legacy machinery protection installation, confirm the complete sensor designation, cable length, connector arrangement, converter output configuration, and monitor scaling before approving a replacement. The PR6424/006-030 + CON021 designation must be checked against the installed assembly rather than treated as proof that every PR6424 sensor is interchangeable. In particular, the standard CON021 and extended-range CON021 variants have different measurement-range specifications. A physically compatible probe paired with the wrong converter can produce incorrect displacement readings.
PR6424/006-030+CON021
Key Technical Specifications
| Parameter | Specification |
|---|---|
| Sensor model | PR6424/006-030 |
| Signal converter | |
| Manufacturer | Emerson EPRO |
| Measurement principle | Eddy-current proximity sensing |
| Sensor family | 16 mm |
| Nominal sensitivity | 4 V/mm (101.6 mV/mil) |
| Linearity | ≤ ±1.5% |
| Nominal center air gap | Approximately 2.7 mm |
| Static measurement range | ±2.0 mm |
| Dynamic measurement range | 0–1,000 µm |
| Standard target material | Ferromagnetic steel, 42CrMo4 reference |
| Minimum shaft diameter | 80 mm |
| Sensor temperature range | Verify applicable sensor revision and installation conditions |
| Converter frequency response | 0–20 kHz at −3 dB |
| Converter rise time | Less than 15 µs |
| Converter supply voltage | −23 to −32 VDC for the −4 to −20 V output configuration |
| Alternative output configuration | −2 to −18 VDC, with the specified supply range |
| Converter operating temperature | −30°C to +100°C |
| Converter enclosure rating | IP20 |
| Sensor connection | Self-locking LEMO connector |
| Converter output | Analog voltage |
Specification note: The sensor values above refer to the 16 mm PR6424 family and the identified model configuration. Confirm the exact cable length, mounting dimensions, temperature limits, and converter pairing against the OEM documentation for the unit being purchased.
Field Engineer’s Pitfall Guide
Warning 1 — Standard-range and extended-range converters are not interchangeable by default.
The standard CON021 supports the PR6424’s specified 4.0 mm total measuring range. Extended-range PR6424 applications use designated converter variants, such as the CON021/914 series. Do not substitute an extended-range converter without confirming the complete sensor and converter ordering codes. Incorrect calibration can distort the indicated shaft displacement even if the output signal appears stable.
Warning 2 — The shaft target must meet the sensor’s installation requirements.
The PR6424 16 mm sensor is specified for ferromagnetic steel targets and a minimum shaft diameter of 80 mm. Target material, shaft curvature, surface condition, and probe positioning can affect the measurement. Do not transfer the installation assumptions from a smaller sensor family without engineering verification.
Warning 3 — Verify the receiving monitor’s voltage scaling and polarity.
The CON021 provides a negative-voltage output configuration. Confirm the actual output variant, supply polarity, monitor input range, channel scaling, and alarm thresholds before returning the measurement channel to service. A polarity or scaling error can produce a misleading reading or an unexpected alarm.
QA & Testing SOP
- Visual and origin inspection: Inspect OEM markings, serial numbers, probe tip, cable jacket, LEMO connector, converter terminals, and signs of prior installation or repair. Record available traceability documentation.
- Electrical checks: Verify converter supply requirements, polarity, output configuration, terminal condition, and cable continuity where applicable.
- Live functional test: Connect the PR6424/006-030 to a compatible CON021 and test it using a suitable calibrated target fixture.
- Measurement diagnostics: Verify sensitivity, linearity, signal stability, and response across the specified measurement range. Confirm that the receiving monitor displays the expected engineering units and direction of movement.
- Documentation: Record the full model numbers, serial numbers, test results, calibration records, and condition assessment. Firmware recording is generally not applicable to this analog probe-and-converter assembly.
- Protective packaging: Protect the sensing face and connector. Secure the cable against crushing, abrasion, and excessive bending, and package the converter to prevent mechanical damage.
Acceptance criterion: A power-on test alone is insufficient. The PR6424/006-030 + CON021 assembly should pass functional measurement checks and match the installed monitoring system’s calibration requirements before acceptance for a protection application.
Technical FAQ
Q1. Can I replace an existing PR6424 probe with the PR6424/006-030?
Only after verifying the full model designation, mounting dimensions, cable assembly, calibration, target geometry, and converter compatibility. A shared PR6424 family designation does not establish complete interchangeability.
Q2. Does the CON021 require firmware flashing before installation?
No routine firmware flashing is specified for the CON021 analog signal converter. Verify electrical compatibility, converter range, output configuration, and sensor calibration instead.
Q3. Can I hot-swap the PR6424/006-030 while the turbine is running?
Do not assume online replacement is permitted. Disconnecting the probe can interrupt a machinery protection channel and may trigger alarms or trips. Follow the plant’s approved isolation, maintenance, and bypass procedures before disturbing a live channel.
Q4. Will the sensor retain its measurement configuration after a power failure?
The PR6424 probe and CON021 converter are analog hardware, not a programmable controller that stores a user application. Channel scaling, alarm thresholds, and trip logic reside in the receiving monitoring system. Verify the restored channel configuration and signal after power returns.
Q5. Does a new-surplus PR6424/006-030 + CON021 assembly include an OEM warranty?
Not automatically. New-surplus is a sales condition, not proof of active manufacturer warranty coverage. Obtain written confirmation of the actual condition, functional test status, warranty provider, coverage period, and return terms before placing the purchase order.
