Product Overview

The EPRO PR6424/013-140 + CON021 Eddy Current Sensor is an eddy current measurement assembly designed for non-contact monitoring of rotating machinery. It is used in industrial condition-monitoring applications where accurate information about shaft movement, displacement, vibration, and mechanical position is required.

The assembly combines an EPRO PR6424 series proximity probe with a CON021 signal converter. The probe detects changes in the distance between its sensing tip and a conductive metallic target. The converter conditions the resulting measurement signal and provides an electrical output that can be connected to compatible machinery monitoring equipment.

Unlike contact-based measurement devices, an eddy current sensor does not need to physically touch the rotating shaft. This makes the technology suitable for continuous monitoring of rotating equipment, including turbines, compressors, pumps, motors, and other machinery with critical rotating components.

The PR6424 series is part of EPRO’s industrial proximity measurement technology. When installed with a compatible extension cable and signal converter, the sensor forms a measuring chain for monitoring shaft displacement and dynamic movement. Correct probe, cable, converter, and target-material matching is essential for accurate measurement.

The CON021 converter provides signal conditioning for the compatible probe system. It helps transform the probe’s measurement response into a usable electrical signal for a monitoring or protection system. The final output characteristics depend on the converter configuration and the associated measuring-chain components.

The supplied product listing identifies the assembly as PR6424/013-140 + CON021, with a sensor head diameter of 16 mm and a weight of 0.32 kg. However, the PR6424/013 model designation is described in available product information as a 13 mm probe-tip version. Buyers should verify the exact probe dimensions and configuration against the product nameplate before ordering.

Technical Specifications

Note: The 16 mm description and PR6424/013 model designation should be checked against the actual nameplate and original technical documentation. Exact measuring range, sensitivity, cable length, temperature limits, and output characteristics depend on the complete measuring-chain configuration.

Function and Working Principle

The PR6424/013-140 + CON021 assembly uses the eddy current principle to measure the distance between a probe and a conductive metallic target. This technology is widely used for non-contact monitoring of rotating machinery.

1. Eddy Current Measurement

An eddy current probe contains a sensing coil that generates an alternating electromagnetic field. When the probe is positioned near a conductive metallic target, the electromagnetic field induces small circulating electrical currents in the target material.

These currents affect the electromagnetic characteristics of the probe. Changes in the gap between the probe and the target therefore produce measurable changes in the probe’s electrical response.

The system uses this relationship to determine the relative distance between the probe tip and the shaft surface.

Because the probe does not need to touch the shaft, it can continuously monitor mechanical movement without introducing contact wear at the measurement point.

2. Shaft Displacement Detection

During machinery operation, rotating shafts may move because of bearing clearance, mechanical loading, thermal expansion, imbalance, misalignment, or other operating conditions.

An eddy current probe can detect changes in the shaft-to-probe gap. The resulting signal provides information about shaft displacement and relative position.

This measurement is useful for identifying changes in machine behavior and supporting condition-based maintenance.

3. Signal Conversion Through CON021

The PR6424 probe generates a measurement response that must be processed before it can be used by a monitoring system.

The CON021 converter is designed to work with compatible EPRO proximity probes. It conditions the probe signal and produces an electrical output corresponding to the measured displacement.

The converter configuration, power supply, output scaling, and wiring must match the specific probe and monitoring-system requirements. The CON021 should not be assumed to provide a standard 4–20 mA output unless that capability is confirmed for the exact configuration.

4. Continuous Monitoring

When installed at an appropriate measurement location, the probe can provide continuous information about shaft movement.

A monitoring system can use this information to identify changes in vibration or shaft position. Operators and maintenance personnel can then investigate abnormal trends before they develop into more serious equipment problems.

The measurement quality depends on correct installation, probe clearance, target material, cable compatibility, converter configuration, and system calibration.

Role in Industrial Machinery Monitoring

The PR6424/013-140 + CON021 measuring assembly can be used as part of a machinery protection or condition-monitoring system.

Shaft Vibration Monitoring

Shaft vibration is an important indicator of rotating machinery condition. Changes in vibration can be associated with imbalance, misalignment, bearing deterioration, looseness, or other mechanical problems.

A properly installed eddy current probe measures relative shaft movement and supplies information that can be evaluated by compatible monitoring equipment.

Shaft Position Monitoring

The probe can also be used to monitor the relative position of a shaft. This is important in machinery where axial or radial movement must remain within defined operating limits.

Position measurements can help maintenance teams identify changes in bearing clearances, mechanical loading, or machine alignment.

Machinery Protection Systems

In critical rotating machinery, displacement measurements may be connected to a dedicated monitoring and protection system. The monitoring equipment evaluates the signal against configured alarm and shutdown limits.

The sensor itself does not independently provide complete machinery protection. Reliable protection requires compatible monitoring hardware, correct channel configuration, appropriate alarm settings, and a properly engineered shutdown strategy.

Integration with DCS and PLC Systems

The conditioned output from the measuring chain may be connected to compatible monitoring equipment or automation systems. Depending on the system architecture, measurement information can be made available to a DCS, PLC, or supervisory monitoring platform.

Engineers must verify electrical signal compatibility, channel scaling, grounding, and isolation requirements before integration.

Industrial Applications

EPRO PR6424 series eddy current sensors are intended for industrial machinery measurement applications where non-contact shaft monitoring is required.

1. Steam Turbines

Steam turbines operate at high rotational speeds and require reliable monitoring of shaft movement and vibration. Eddy current probes can be installed at suitable bearing locations to measure relative shaft displacement.

Continuous measurement helps operators evaluate changes in turbine operating conditions and identify abnormal mechanical behavior.

2. Gas Turbines

Gas turbines contain high-speed rotating components that operate under demanding thermal and mechanical conditions. Shaft displacement monitoring can provide useful information about rotor behavior and machine stability.

Probe temperature limits, cable specifications, and installation requirements must be checked against the actual turbine environment.

3. Industrial Compressors

Centrifugal and other rotating compressors may require continuous shaft vibration and position monitoring. Eddy current measurement systems can provide non-contact information about shaft movement at selected bearing locations.

This information supports machinery condition assessment and maintenance planning.

4. Pumps and Motors

Large industrial pumps and motors may experience shaft movement caused by bearing wear, imbalance, alignment problems, or changing process loads.

An appropriately configured proximity measurement system can help maintenance teams monitor relative shaft movement and identify changes that warrant inspection.

5. Gearboxes and Rotating Equipment

Industrial gearboxes and other rotating machines may use displacement monitoring to evaluate shaft behavior and mechanical stability.

The probe location and measurement direction should be selected according to the machine design and the condition being monitored.

Installation and System Integration

Correct installation is essential for obtaining stable and repeatable measurements from an eddy current sensor.

1. Verify the Complete Measuring Chain

Before installation, confirm that the PR6424 probe, extension cable, and CON021 converter are designed to operate together.

The complete model numbers and cable configuration should be checked. Using an incompatible extension cable or converter may change the measuring characteristics and result in inaccurate readings.

2. Confirm Probe Dimensions and Mounting

Verify the probe head diameter, mounting thread, insertion length, and available installation space. The supplied product description identifies a 16 mm sensor head, but the PR6424/013 model designation should be checked against the original product documentation.

The probe should be mounted securely. Excessive vibration or movement of the mounting bracket can introduce measurement errors.

3. Set the Correct Probe Gap

The initial clearance between the probe tip and the shaft must follow the specifications for the exact measuring system.

An incorrect initial gap may reduce the usable measurement range or cause the signal to operate outside its calibrated region.

Use the manufacturer’s installation and calibration procedure rather than relying on a generic gap value.

4. Check Target Material

Eddy current probes are designed for conductive targets. Their measuring characteristics depend on the electrical and magnetic properties of the target material.

For rotating machinery applications, the target material and shaft surface condition should match the requirements of the selected probe system.

5. Route and Connect the Cable

Use the specified cable type and connectors. Route sensor cables away from high-current power conductors, variable frequency drive output cables, and other potential sources of electrical interference.

Observe the manufacturer’s shielding and grounding instructions. Poor cable routing or incorrect grounding can introduce noise into the measurement signal.

6. Configure the CON021 Converter

Confirm the converter’s power supply, terminal connections, probe compatibility, and output scaling.

The converter must be configured according to the associated probe and monitoring-system requirements. Do not assume that settings from another PR6424 model are interchangeable.

7. Calibrate and Test the System

After mechanical installation and electrical connection, verify the measuring-chain response using the manufacturer’s calibration procedure.

Check the output at known probe gaps where suitable calibration equipment is available. Confirm signal stability, scaling, and monitoring-channel operation before placing the machine into normal service.

Compatible System Components

The PR6424/013-140 + CON021 assembly operates as part of a complete proximity measurement system.

The components listed above describe a typical measuring-chain arrangement. They are not necessarily all included in the supplied product package.

Alternative Models and Replacement Considerations

The PR6424 series includes different probe configurations. Replacement selection should be based on the complete model number rather than the series name alone.

Before replacing an existing sensor, compare:

• Complete probe model number.
• Probe head or tip diameter.
• Probe mounting thread and insertion length.
• Integrated cable length and extension cable type.
• Converter model and electrical configuration.
• Measuring range and sensitivity.
• Initial air-gap requirements.
• Target material and shaft dimensions.
• Operating temperature and environmental conditions.
• Monitoring-system input requirements.

A probe with the same general appearance may have different electrical characteristics. Replacing only the probe or converter without checking the complete measuring chain can lead to incorrect readings.

Key Advantages

Non-Contact Measurement

The eddy current principle allows the probe to measure shaft movement without physical contact with the rotating surface. This avoids mechanical contact wear at the measurement point.

Continuous Shaft Monitoring

The system can provide ongoing measurement information for machinery condition monitoring and operational assessment.

Displacement and Position Measurement

The probe can detect changes in the distance between its sensing tip and a conductive metallic target, supporting shaft displacement and position monitoring.

Signal Conditioning

The CON021 converter processes the compatible probe signal for connection to an appropriate monitoring system.

Rotating Machinery Applications

The PR6424 series is used in industrial machinery measurement applications involving turbines, compressors, pumps, motors, and other rotating equipment.

Support for Condition-Based Maintenance

Continuous measurement trends can help maintenance teams identify changes in machinery behavior and plan inspections according to equipment condition.

Technical FAQs

1. What is the EPRO PR6424/013-140 + CON021?

It is an eddy current measurement assembly combining a PR6424 series proximity probe with a CON021 signal converter. It is used for non-contact measurement of shaft displacement and relative position in rotating machinery.

2. What does an eddy current sensor measure?

An eddy current sensor measures changes in the distance between its sensing tip and a conductive metallic target. In rotating machinery, this measurement can be used to monitor shaft displacement and vibration.

3. What is the function of the CON021 converter?

The CON021 conditions the measurement signal from a compatible EPRO proximity probe and provides an electrical output for a suitable monitoring system.

4. Is the PR6424/013-140 a 16 mm probe?

The supplied product description identifies it as a 16 mm sensor. However, available product listings describe the PR6424/013 designation as a 13 mm probe-tip version. Verify the exact probe dimensions using the nameplate or original manufacturer documentation before purchasing.

5. Does the sensor contact the rotating shaft?

No. Eddy current measurement is non-contact. The probe is mounted with a controlled clearance from the conductive shaft surface.

6. Can the assembly monitor shaft vibration?

It can provide relative shaft displacement measurements that are used by compatible monitoring equipment to evaluate shaft vibration.

7. Can it be connected directly to a PLC?

The probe should be connected through its compatible signal converter. The converter output can then be connected to suitable monitoring or automation equipment after checking signal type, voltage range, scaling, and input requirements.

8. Is the CON021 converter included?

The combined model designation PR6424/013-140 + CON021 indicates a probe-and-converter configuration. Confirm the actual package contents with the supplier before ordering.

9. What should be checked before replacing an existing EPRO probe?

Check the full probe model, head dimensions, cable configuration, converter model, measuring range, sensitivity, mounting arrangement, and monitoring-system settings.

10. What is the listed weight of this product?

The supplied product listing specifies a weight of 0.32 kg. Confirm whether this represents the probe assembly alone or the complete supplied package before calculating shipping weight.

Procurement and Maintenance Recommendations

When purchasing the EPRO PR6424/013-140 + CON021 assembly, verify the complete probe and converter model numbers. Pay particular attention to the sensor head diameter because the supplied 16 mm description differs from available information for the PR6424/013 model designation.

Request clear photographs of the probe label, connector, cable, and converter identification plate. Confirm whether the quoted assembly includes the probe, converter, and any required extension cable. These details affect both installation and the total measuring-chain configuration.

For maintenance, inspect the probe mounting arrangement, cable condition, connectors, and converter terminals. Check for loose connections, damaged insulation, contamination, or mechanical movement of the mounting bracket.

Where measurement accuracy is important, follow the manufacturer’s calibration procedure and retain records of the initial gap, calibration values, converter configuration, and monitoring-channel settings.

For replacement projects, avoid mixing components from different probe configurations without confirming compatibility. The complete measuring chain should be evaluated to ensure that the replacement provides the required measurement range and output characteristics.

Conclusion

The EPRO PR6424/013-140 + CON021 Eddy Current Sensor is a non-contact measurement assembly designed for monitoring shaft displacement and relative movement in industrial rotating machinery. Its probe detects changes in the distance to a conductive metallic target, while the CON021 converter conditions the measurement signal for compatible monitoring equipment.

The assembly can support condition monitoring for turbines, compressors, pumps, motors, and other rotating equipment. Correct probe selection, cable matching, converter configuration, mounting, and calibration are essential for reliable measurements.

Before listing or purchasing this model, verify the discrepancy between the supplied 16 mm sensor description and the PR6424/013 model designation. Accurate identification helps ensure that the selected sensor matches the original installation and the required monitoring performance.