Product Overview

The EPRO PR6424/010-040+CON021 16 mm Eddy Current Sensor is a non-contact displacement measurement system designed for monitoring the operating condition of rotating machinery. Manufactured under the EPRO product line associated with Emerson, this sensor system is used in industrial machinery protection and condition monitoring applications where accurate shaft displacement and vibration measurements are important.

The system combines a PR6424 eddy current probe with a CON021 signal converter. The sensor detects changes in the distance between its probe tip and a conductive target, such as a rotating machine shaft. The converter processes the sensor signal and provides an output suitable for connection to compatible machinery monitoring equipment.

Unlike contact-based measurement devices, an eddy current sensor does not need to touch the rotating shaft. This non-contact measurement method makes it suitable for continuous monitoring of machinery operating at high speeds and under demanding industrial conditions.

The PR6424 family is designed for critical turbomachinery applications, including steam turbines, gas turbines, hydro turbines, compressors, pumps, and fans. It can be used to measure radial and axial shaft dynamic displacement, static position, eccentricity, and speed-related parameters.

The PR6424/010-040+CON021 configuration is identified by its 16 mm sensor head diameter and associated CON021 signal converter. Its application requires correct sensor installation, a compatible target material, appropriate converter configuration, and proper integration with the machinery protection system.

For industrial maintenance teams, this type of sensor provides important information about shaft movement and machine operating conditions. Continuous measurement can help identify abnormal vibration or displacement trends before they develop into more serious mechanical problems.

Technical Specifications

Note: Specifications for the PR6424 sensor family are shown above. Actual measurement-chain performance depends on the exact probe configuration, cable arrangement, converter version, calibration, and installation conditions. The supplied weight of 0.32 kg is retained as the listing value.

Function and Working Principle

The PR6424/010-040+CON021 uses the eddy current measurement principle to detect the distance between the sensor probe and a conductive target. This technology is widely used in rotating machinery because it allows continuous displacement measurement without physical contact.

1. Non-Contact Displacement Measurement

The sensor generates an electromagnetic field around its probe tip. When a conductive target approaches the probe, eddy currents are induced in the target surface.

Changes in the distance between the probe and target affect the electromagnetic characteristics of the sensor. The resulting electrical signal changes according to the measured gap.

By monitoring these changes, the system can determine the relative movement of a machine shaft. This makes it possible to measure shaft vibration, axial displacement, and static position.

Because the probe does not physically contact the shaft, the measurement process does not introduce mechanical friction or wear at the sensing point.

2. Eddy Current Signal Conversion

The PR6424 probe operates together with the CON021 signal converter. The converter supplies the required excitation and processes the probe signal.

It converts the sensor’s response into a standardized output that can be used by compatible machinery monitoring equipment.

The converter must be matched to the sensor type and measuring range. Incorrect converter selection or calibration can result in inaccurate displacement readings.

3. Shaft Vibration Measurement

When a rotating shaft moves away from its normal centerline, the distance between the shaft surface and the probe changes.

The sensor detects these variations continuously. The resulting measurement can be used to evaluate radial shaft vibration and identify changes in machine operating conditions.

Vibration measurements are particularly important for turbines, compressors, and other rotating machines because excessive shaft movement may indicate mechanical imbalance, misalignment, bearing problems, or other developing faults.

4. Axial Position Monitoring

The PR6424 measurement system can also be applied to axial shaft displacement monitoring.

Axial movement may occur because of changes in thrust loading, bearing conditions, thermal expansion, or mechanical wear. Monitoring axial position helps operators understand whether the shaft is operating within its permitted movement range.

In critical machinery, axial displacement measurements may form part of the machine protection strategy.

5. Eccentricity and Speed-Related Monitoring

The sensor can also support eccentricity and speed/key-related measurements when installed in an appropriate measurement arrangement.

Eccentricity monitoring helps identify deviations in shaft geometry or rotation. Speed-related signals can be used by compatible monitoring equipment for rotational speed measurement and machine-condition analysis.

The exact measurement function depends on the probe location, target arrangement, converter configuration, and monitoring system.

Role in Industrial Machinery Protection Systems

The PR6424/010-040+CON021 is designed for use in machinery condition monitoring and protection systems. It provides measurement information that helps operators evaluate the mechanical condition of important rotating equipment.

1. Integration with Machinery Monitoring Equipment

The CON021 converter processes the probe signal and supplies an output to compatible monitoring equipment.

Depending on the installation, this information may be used by machinery monitoring platforms to display shaft displacement, vibration trends, and alarm conditions.

The complete measurement chain must be configured correctly, including the sensor, converter, interconnecting cable, and monitoring input.

2. Continuous Machine Condition Monitoring

Continuous monitoring allows operators to observe changes in machine behavior during normal operation.

Instead of relying only on periodic inspections, maintenance teams can review measurement trends and identify abnormal conditions as they develop.

For example, an increase in shaft vibration may indicate a developing mechanical problem. Engineers can investigate the cause and determine whether maintenance is required.

3. Alarm and Protection Functions

In critical machinery applications, displacement and vibration measurements may be connected to alarm and shutdown logic.

When measured values exceed configured limits, the monitoring system can generate warnings or initiate protective actions according to the plant’s operating philosophy.

Alarm and trip thresholds must be established by qualified engineers based on machine design, manufacturer recommendations, and applicable protection requirements.

4. Support for Predictive Maintenance

Historical sensor data can help maintenance teams identify changes in machinery condition over time.

By reviewing vibration and displacement trends, engineers may detect developing mechanical problems and plan inspections or maintenance activities before an unexpected failure occurs.

The sensor provides measurement data; accurate diagnosis still requires appropriate monitoring equipment, engineering analysis, and knowledge of the machine.

Industrial Applications

The EPRO PR6424 series is intended for critical rotating machinery where reliable displacement and vibration measurements are required.

1. Steam Turbines

Steam turbines operate at high rotational speeds and require continuous monitoring of shaft movement.

The PR6424 sensor can be installed in suitable turbine monitoring arrangements to measure radial shaft vibration and axial displacement.

These measurements help operators identify changes in shaft behavior that may be associated with rotor imbalance, bearing wear, misalignment, or other mechanical conditions.

2. Gas Turbines

Gas turbines are important components in power generation and industrial energy systems.

Their rotating assemblies operate under demanding thermal and mechanical conditions. Shaft vibration and position monitoring are therefore important for equipment protection.

The PR6424 sensor system can provide displacement information for compatible gas turbine monitoring installations.

3. Hydro Turbines

Hydro turbines operate in power generation facilities and require monitoring of rotating shaft movement and mechanical stability.

Eddy current sensors can be used in appropriate arrangements to measure shaft displacement and vibration.

The collected data supports equipment condition assessment and maintenance planning.

4. Industrial Compressors

Large compressors are used in petrochemical plants, refineries, gas processing facilities, and other industrial operations.

Shaft vibration and axial displacement monitoring help engineers evaluate compressor operating conditions.

The PR6424 system can be applied to compatible compressor monitoring systems to provide continuous measurement of shaft movement.

5. Industrial Pumps

Critical process pumps may operate continuously in demanding industrial environments.

Monitoring shaft vibration and position can help maintenance teams identify abnormal mechanical conditions, including changes associated with bearing deterioration or rotor imbalance.

The sensor must be installed according to the pump’s monitoring design and the required measurement range.

6. Industrial Fans

Large industrial fans are used in ventilation, cooling, combustion air, and material-processing systems.

In suitable installations, eddy current sensors can monitor shaft displacement and vibration to support condition-based maintenance.

Installation and System Integration

Correct installation is essential for obtaining accurate measurements from the PR6424/010-040+CON021 system.

1. Verify the Sensor and Converter Configuration

Before installation, confirm that the PR6424 probe and CON021 converter are compatible.

The complete ordering code should be checked against the equipment documentation. Confirm the probe configuration, cable arrangement, connector type, and converter measuring-range requirements.

Do not assume that all PR6424 probes and CON021 converters are interchangeable without checking their specifications.

2. Select a Suitable Measuring Position

The sensor must be installed at a location that provides a stable and suitable measurement target.

For shaft vibration measurement, the probe is generally positioned close to the rotating shaft surface according to the machinery manufacturer’s monitoring design.

For axial displacement measurement, the installation arrangement must allow the sensor to detect the required axial movement.

The probe position should avoid mechanical interference and provide adequate clearance throughout the shaft’s operating range.

3. Check the Target Material

The PR6424 sensor family is designed for use with specified conductive ferromagnetic target materials. The standard reference material is 42CrMo4 steel.

Differences in target material, surface condition, geometry, and shaft diameter can affect measurement performance.

Before commissioning, verify that the actual shaft material and target dimensions are suitable for the sensor’s calibration.

4. Set the Correct Air Gap

The sensor must be positioned within its specified operating range.

The nominal center air gap for the PR6424 family is approximately 2.7 mm. The correct gap should be established using the manufacturer’s installation procedure and the relevant calibration information.

Incorrect air-gap adjustment can result in measurement errors or insufficient operating range.

5. Route and Protect the Sensor Cable

The sensor cable should be routed carefully to avoid mechanical damage, excessive bending, heat exposure, and electromagnetic interference.

Keep sensor wiring away from high-power conductors where required by the installation design.

Ensure that connectors are properly secured and that cable shielding and grounding follow the manufacturer’s recommendations.

6. Connect the CON021 Converter

The CON021 converter should be installed and connected according to its technical documentation.

Verify the power supply, sensor connections, output wiring, and monitoring-system input configuration.

The converter’s measuring range must correspond to the sensor configuration and intended application.

7. Commission and Verify Measurement Performance

After installation, check the sensor’s electrical connections and establish the correct air gap.

Verify the output signal under suitable operating conditions and compare the measurement with the expected machine position or vibration behavior.

Record the installation details and calibration information for future maintenance and troubleshooting.

Compatible System Components

The PR6424/010-040+CON021 operates as part of a complete machinery measurement chain. The following components may be used in a suitable monitoring installation.

The listed components are examples of a typical measurement arrangement. They are not necessarily included in the product package.

Alternative Models and Replacement Considerations

The PR6424 sensor belongs to the EPRO eddy current sensor family. Related models may provide different probe configurations, measurement ranges, or installation characteristics.

When replacing a PR6424 sensor, check the following:

• Complete sensor catalog number.
• Probe diameter and mechanical dimensions.
• Cable length and connector arrangement.
• Sensor operating temperature.
• Measuring range and sensitivity.
• Target material and shaft diameter.
• Converter model and calibration.
• Monitoring-system input compatibility.
• Installation location and required air gap.

A related sensor from the same product family should not automatically be treated as a direct replacement. The complete measurement chain must be verified.

Key Advantages

Non-Contact Measurement

The sensor measures shaft displacement without physical contact, avoiding mechanical wear at the sensing point.

Continuous Shaft Monitoring

It supports continuous measurement of shaft movement, making it suitable for machinery condition monitoring applications.

Vibration and Position Measurement

The PR6424 family supports radial and axial displacement, static position, eccentricity, and speed/key-related monitoring arrangements.

Compatibility with CON021

The PR6424 probe can be used with the compatible CON021 signal converter to create a complete measurement chain.

Industrial Machinery Applications

The sensor family is designed for demanding rotating machinery, including turbines, compressors, pumps, and fans.

Support for Predictive Maintenance

Continuous measurement data can help maintenance teams identify abnormal operating trends and plan inspections more effectively.

Established EPRO Measurement Technology

The PR6424 family is used in industrial machinery monitoring applications where reliable shaft displacement measurements are required.

Technical FAQs

1. What is the EPRO PR6424/010-040+CON021?

It is an eddy current displacement sensor system consisting of a PR6424 probe and a CON021 signal converter. It is used for non-contact measurement of shaft displacement and vibration in rotating machinery.

2. What is the sensor head diameter?

The supplied product configuration specifies a 16 mm sensor head diameter.

3. What is the function of the CON021 converter?

The CON021 provides the required sensor excitation and processes the probe signal into an output suitable for compatible machinery monitoring equipment.

4. What parameters can the PR6424 sensor measure?

Depending on the installation arrangement, the PR6424 family can measure radial and axial shaft displacement, static position, eccentricity, and speed/key-related parameters.

5. What is the measurement range?

The PR6424 family has a static measurement range of ±2.0 mm and a dynamic measurement range of 0–1,000 μm under the specified standard configuration.

6. What is the nominal air gap?

The nominal center air gap is approximately 2.7 mm. The actual installation should follow the manufacturer’s setup and calibration instructions.

7. Which industries use this sensor?

Typical applications include power generation, petrochemical processing, oil and gas, industrial manufacturing, and facilities operating critical rotating machinery.

8. Can the PR6424 sensor be used without a signal converter?

The PR6424 probe is designed to operate as part of a compatible measurement chain. The appropriate signal converter or supported monitoring-system interface is required to process its measurement signal.

9. What should be checked before replacing the sensor?

Verify the full model number, probe diameter, cable configuration, converter compatibility, measurement range, target material, and installation dimensions.

10. What is the listed weight of this model?

The supplied product listing weight is 0.32 kg. Confirm whether this value includes the converter, cables, and packaging before using it for shipping calculations.

Procurement and Maintenance Recommendations

When purchasing the EPRO PR6424/010-040+CON021, verify the complete ordering code and confirm that the probe and CON021 converter are supplied in the required configuration.

For replacement projects, compare the existing sensor’s diameter, cable arrangement, connector type, and measuring range. Also confirm that the replacement converter is suitable for the probe and monitoring system.

For used or refurbished equipment, request clear photographs of the sensor label, probe tip, cable, connector, and converter. Check for physical damage, cable deterioration, corrosion, and signs of improper handling.

During maintenance, inspect the probe mounting, cable routing, connector condition, and converter wiring. Monitor the measurement output for unexpected changes and investigate abnormal trends rather than relying only on individual readings.

Keep the sensor installation and calibration records with the machinery maintenance documentation. This information helps engineers identify the correct replacement configuration and maintain consistency across future inspections.

Conclusion

The EPRO PR6424/010-040+CON021 16 mm Eddy Current Sensor is a non-contact measurement system designed for monitoring shaft displacement and vibration in critical rotating machinery. Its PR6424 probe works with the CON021 signal converter to provide measurement information for compatible machinery monitoring and protection systems.

With applications in turbines, compressors, pumps, and industrial fans, the PR6424 sensor family supports continuous machinery condition monitoring and predictive maintenance strategies.

For procurement and replacement work, verifying the complete model number, probe configuration, converter compatibility, cable arrangement, and installation requirements is essential to ensure reliable measurement performance.