Comprehensive Analysis and Application Guide for Vibro-Meter Piezoelectric Accelerometer Systems
Introduction: The Central Role of Vibration Monitoring and Piezoelectric Sensing Technology in Modern Industry
In modern industrial systems, condition monitoring and fault prediction of mechanical equipment have become critical to ensuring production safety and improving operational efficiency. Rotating machinery such as turbines, compressors, and generators, in particular, have vibration characteristics that directly reflect the operational health of the equipment. Vibration monitoring technology detects and analyzes mechanical vibration signals to identify early signs of imbalance, misalignment, bearing wear, gear faults, and other issues, thereby preventing catastrophic failures and enabling predictive maintenance.
Among various vibration sensor technologies, piezoelectric accelerometers have become the most widely used sensing devices in industrial vibration monitoring due to their unique performance advantages. Vibro-Meter SA of Switzerland, as a specialized technical provider in this field, offers its CA XXX and CE XXX series piezoelectric accelerometer systems. Known for their high reliability, wide temperature range adaptability, and suitability for use in potentially explosive atmospheres, these systems are extensively employed in critical global industries such as energy, chemicals, aviation, and marine.
Based on the "Instruction Manual for Piezoelectric Accelerometers CA XXX/CE XXX Series" (Edition 4) published by Vibro-Meter, this article systematically analyzes the technical principles, model classifications, installation specifications, safety requirements, and application practices of this product series. The aim is to provide comprehensive and in-depth technical reference for engineering and technical personnel, supporting the optimal design and reliable operation of industrial equipment vibration monitoring systems.
Chapter 1: Technical Principles of Piezoelectric Accelerometers and the Vibro-Meter Product System
1.1 Piezoelectric Effect and Acceleration Measurement Principle
The core physical basis of a piezoelectric accelerometer is the piezoelectric effect—a physical phenomenon where certain crystalline materials (such as quartz or ceramic) generate an electric charge when subjected to mechanical stress. Vibro-Meter accelerometers utilize either compression or shear-type structural designs, precisely assembling piezoelectric crystal elements with an inertial mass. When the sensor vibrates with the measured object, the inertial mass applies periodic stress to the piezoelectric crystal, generating a charge signal proportional to the acceleration.
As shown in Manual Figures 1-4 and 1-5, in the compression-type structure, the crystal cells are subjected to compressive force along the sensitive axis, while in the shear-type structure, they are subjected to shear force. Both structures have their advantages: compression types typically offer higher stiffness and resonant frequency, suitable for high-frequency measurements; shear types are less sensitive to base strain and temperature variations, providing better environmental adaptability.
The frequency response range of piezoelectric accelerometers is typically from 3 Hz to above 20 kHz, covering the vibration frequency characteristics of most industrial rotating machinery. Their operating temperature range can be as wide as -196°C to +620°C, a feature that allows them to operate reliably in extreme temperature environments, such as near heat sources in gas turbines or on cryogenic pumping equipment.
1.2 Vibro-Meter Accelerometer Product Classification System
Vibro-Meter categorizes its piezoelectric accelerometer systems into three main classes, based on the integration method of the signal conditioning electronics with the sensing head:
1.2.1 Accelerometers with Separate Electronic Conditioner (CA Series)
These accelerometers (e.g., CA 134, CA 135, CA 136, CA 201, CA 216, CA 902, CA 905) contain only the piezoelectric sensing element, outputting a charge signal proportional to acceleration (sensitivity typically expressed in pC/g). The charge signal is transmitted via a dedicated low-noise cable to a separate charge converter (e.g., IPC XXX series), where it is converted into a current-modulated signal. The main advantage of this design is that the sensing head can withstand very high or very low temperature environments (from -54°C to +620°C, depending on the specific model), making it suitable for measurement points close to heat or cold sources.
1.2.2 Accelerometers with Attached Electronic Conditioner (CE 134/136 Series)
These accelerometers feature the electronic conditioner as a separate module attached to the end of the sensing head cable (not integrated into the same housing). The charge signal is converted into a current-modulated signal within the attached conditioner. This design balances temperature adaptability and system simplification: the sensing head can operate in environments from -70°C to +350°C (CE 134) or -54°C to +260°C (CE 136), while the electronic conditioner operates between -30°C and +100°C.
1.2.3 Accelerometers with Incorporated Electronic Conditioner (CE 310 Series)
These accelerometers have the electronic conditioning circuit fully integrated within the sensing head housing, directly outputting a current-modulated signal and eliminating the need for an external charge converter. They offer the most compact structure and simplest installation, but their operating temperature range is limited by the internal electronics: -30°C to +150°C for the standard version and -30°C to +100°C for the explosion-proof version.
1.3 Model Selection Guide: Balancing Temperature and Frequency
Manual Figures 1-1 to 1-3 provide detailed selection guidance, showing the operating temperature ranges and frequency response characteristics of different models. Selection requires comprehensive consideration of:
Measurement Point Temperature: Temperature resistance varies significantly between models. For example, the CA 905 can withstand up to 620°C, while the standard CE 310 is limited to 150°C.
Vibration Frequency Range: All piezoelectric accelerometers cover the basic 3 Hz - 20 kHz range, but different models have variations in resonant frequency and linear response intervals.
Environmental Conditions: Presence of potentially explosive atmospheres (requiring Ex i versions), humidity, corrosiveness, etc.
Installation Space Constraints: The incorporated type is most compact; the separate type requires additional space for the charge converter.
Signal Transmission Distance: Current-modulated signals (based on the 4-20mA principle) can be transmitted over 1000 meters without significant distortion, making them ideal for large industrial sites.
Chapter 2: Measurement Chain System Architecture and Signal Transmission Technology
2.1 Composition of a Complete Vibration Monitoring System
A Vibro-Meter vibration measurement chain is a complete system for signal acquisition, conditioning, transmission, and processing, typically consisting of the following components:
Accelerometer Sensing Head: Converts mechanical vibration into a raw charge signal.
Connection Cable: Low-noise coaxial cable; some models come with a stainless steel braided sheath (BOA type) for mechanical protection.
Signal Conditioner:
Transmission Cable: Two-core shielded cable (K 2XX series) for transmitting the current-modulated signal.
Galvanic Separation Unit (GSI XXX): Eliminates ground loop interference, provides safe power to the front end, and converts the current signal to a voltage signal.
Electronic Processing System: Such as Vibro-Meter's MMS or VM 600 monitoring systems, for signal analysis, alarming, and recording.
2.2 Advantages of Signal Conversion and Transmission Technology
The raw output of a piezoelectric accelerometer is a high-impedance charge signal, highly susceptible to cable capacitance, electromagnetic interference, and ground loops. The Vibro-Meter system addresses these issues through a two-stage conversion:
First Stage: Charge-to-Current Conversion
Performed in the Charge Converter (IPC) or incorporated conditioner.
Utilizes current modulation technology (similar to the 4-20mA transmitter principle).
Conversion ratio is typically 4mA corresponding to 0 g and 20mA to full-scale acceleration.
Second Stage: Current-to-Voltage Conversion
Performed in the Galvanic Separation Unit (GSI).
Also provides two-wire loop power (typically 24 VDC).
Outputs a voltage signal that can be directly connected to PLCs, DCSs, or dedicated monitoring systems.
Advantages of this two-stage conversion architecture:
Strong Noise Immunity: Current signals are insensitive to electromagnetic interference.
Long Transmission Distance: Can exceed 1000 meters without significant signal degradation.
Simplified Wiring: Only a two-core cable is needed for both signal and power.
Intrinsic Safety: Suitable for potentially explosive atmospheres (when used with certified barriers).
2.3 Four Typical Measurement Chain Configurations
Manual Chapter 2 details four typical configurations:
2.3.1 Accelerometer with Connector + Separate Electronic Conditioner
Suitable for models like CA 902, CA 905, CA 135, and certain CA 134/136 versions. The accelerometer has a 7/16"-27 UNS-2A connector and requires a dedicated connecting cable. The charge converter is housed in a waterproof polyester enclosure, with cable glands ensuring the protection rating.
2.3.2 Accelerometer with Integral Cable + Separate Electronic Conditioner
Suitable for models like CA 201, CA 216, and certain CA 134/136 versions. The accelerometer comes factory-connected with a low-noise cable featuring a BOA sheath, which connects directly to the charge converter. This simplifies field installation and reduces the risk of connection point failures.
2.3.3 Accelerometer with Attached Electronic Conditioner
Suitable for CE 134 and CE 136. The conditioner is fixed to the end of the cable and is not detachable from the sensing head. The cable is welded to both housings, ensuring mechanical strength and sealing.
2.3.4 Accelerometer with Incorporated Electronic Conditioner
Suitable for CE 310. The conditioning circuit is fully integrated into the sensing head, and a junction box (JB XXX) is used to connect the transmission cable. This offers the most compact structure and simplest installation.
Chapter 3: Installation Techniques and Mechanical Considerations
3.1 Principles for Selecting Installation Location
Choosing the correct installation location is fundamental to obtaining accurate vibration data. Manual Figure 4-1 illustrates recommended mounting points:
As Close as Possible to Bearings: Bearings are the connection point between the rotor and stator, best reflecting the machine's vibration state.
On Rigid Structural Parts: Avoid mounting on machine casings or structures with insufficient stiffness, as these may exhibit local resonances that amplify or attenuate actual vibration.
Accessibility and Safety: Balance measurement needs with maintenance convenience and ensure safe installation and removal.
Environmental Factors: Consider temperature, corrosion, electromagnetic interference, etc.
3.2 Mounting Surface Preparation Requirements
Proper surface preparation is crucial for measurement accuracy:
Surface Flatness: Within 0.01 mm (Manual Figures 5-2, 6-2, 7-2).
Surface Roughness: Grade N7 or better.
Perpendicularity to Sensitive Axis: The mounting surface should be perpendicular to the accelerometer's sensitive axis.
Cleanliness: Free of oil, rust, coatings, etc.
Specific machining steps (using CA 201 as an example):
Mark the positions for four threaded holes at the chosen location.
Drill four holes: 4.8 mm diameter, 20 mm deep.
Tap M6 threads to a depth of 14 mm.
Prepare M6 x 35 hexagon socket head cap screws and spring lock washers.
Apply LOCTITE 241 locking adhesive to the screws.
Tighten using a torque wrench, not exceeding 15 Nm.
3.3 Influence of Mounting Method on Measurement Accuracy
Manual Chapter 3 systematically analyzes the influence of different mounting methods on frequency response, referencing the ISO 5348 standard:
3.3.1 Threaded Mounting (Optimal)
Use the torque values recommended by the manufacturer (typically 2-15 Nm, depending on the model).
Provides the widest effective frequency range (up to 30 kHz).
Minimal phase distortion.
3.3.2 Adhesive Mounting
Methyl cyanoacrylate cement: Maximum 80°C, acceptable frequency response.
Double-sided adhesive tape: Maximum 95°C, limited frequency response, especially with thick tape.
Beeswax film: Maximum 40°C, suitable only for temporary low-frequency measurements.
3.3.3 Other Temporary Mounting Methods
Magnetic base: Maximum 150°C, severely limited frequency response.
Hand-held probe: Suitable only for rough checks, frequency response drops to below 2 kHz.
Figure 3-1 quantitatively shows the amplitude error and phase shift caused by different mounting methods. For precise measurements and comparison of data from multiple points, consistent mounting methods are essential.
3.4 Cable Routing Specifications
Improper cable routing can introduce noise and signal distortion:
Minimum Bending Radius: Not less than 50 mm.
Fixing Spacing: Use clips every 100-200 mm.
Avoid Stress: The cable should exit from the vibration plane, not directly from the sensor (Figure 3-8).
Keep Away from Interference Sources: Avoid running parallel to high-voltage cables or high-frequency transmission lines.
Mechanical Protection: Use KS 106 stainless steel flexible conduit in areas prone to damage.
3.5 Key Points for Installing Electronic Units
Charge Converter (IPC):
Should be installed in a location with minimal or no vibration.
Ambient temperature range: -25°C to +70°C.
Typically installed in an ABA 160 industrial housing with IP65 protection rating.
Galvanic Separation Unit (GSI):
Ambient temperature range: 0°C to +55°C.
Typically installed on a DIN rail inside a cabinet.
A dedicated mounting kit is available (bracket, positioning lug, M4 fixing screw).
Junction Box (JB):
Chapter 4: Electrical Connections and Grounding Techniques
4.1 Cable Connection Techniques
Correct electrical connections are key to ensuring signal quality and system reliability:
4.1.1 General Connection Steps
Strip cable insulation as needed (typically 4-6 mm).
Route cable through the cable gland into the housing.
Connect to the corresponding terminal block.
Install the Ø8 circlip to prevent cable slippage.
Tighten the cable gland to ensure sealing.
4.1.2 Cable Gland Installation Details (Figures 5-12, 7-11)
Unscrew element 1 counterclockwise (do not remove element 5 from the housing).
Pull out elements 2 and 3 (these adapt to different cable diameters).
Thread the cable through the elements.
Reassemble and tighten the gland components.
Check that the cable is securely held to ensure waterproof sealing.
4.2 Shielding and Grounding Strategies
Proper shielding and grounding are crucial for preventing electromagnetic interference:
Shield Connection at the Sensor End:
The cable shield should be connected to the sensor housing at the sensor end.
For insulated-mounted sensors, a short wire must be connected between the negative (-) terminal and the shield terminal inside the junction box or connector (Figures 6-10, 7-10).
Transmission Cable Shield Treatment:
System Grounding Architecture:
Follow the single-point grounding principle.
The Galvanic Separation Unit provides isolation between the signal ground and the cabinet ground.
Industrial housings should be reliably grounded via their mounting bolts.
4.3 Connector Assembly Specifications
For models with connectors (e.g., CG 134), assembly requires special attention:
Dismantle the connector assembly.
Solder the cable wires to the corresponding pins (A, B, C) as per Figure 6-9.
Solder a jumper wire between pins B and C (to eliminate leakage current and ground loop interference when the sensor is correctly grounded).
Apply LOCTITE 241 locking adhesive to the threads.
Reassemble the connector, ensuring the cable is not twisted.
Insert into the mating connector, tightening to 7-11 Nm torque.
4.4 Galvanic Separation Unit Connections
Strip the transmission cable wires and crimp AMP Faston 6.3 terminals.
Insert into the corresponding terminals on the GSI (Figures 5-13, 6-11, 7-12).
Connect the system-side cable with similarly crimped terminals.
Observe polarity markings: typically "+" for power positive, "-" for signal/power negative.
Chapter 5: Application Specifications for Potentially Explosive Atmospheres
5.1 ATEX Directive and Explosion-Proof Certification
Vibro-Meter products have undergone stringent certification for use in potentially explosive atmospheres, complying with the European ATEX Directive 94/9/EC requirements. Manual Appendix B provides the complete EC Type Examination Certificates:
5.1.1 Intrinsic Safety Protection Types
"ia" Level: Suitable for Zone 0 (where an explosive atmosphere is present continuously or for long periods).
"ib" Level: Suitable for Zone 1 (where an explosive atmosphere is likely to occur occasionally in normal operation).
5.1.2 Gas Group Classification
Group IIC: Represents the most easily ignited gases (e.g., hydrogen, acetylene).
Group IIB: Medium ignition risk gases.
Group IIA: General ignition risk gases.
5.1.3 Temperature Class
T1 to T6: Indicates the maximum surface temperature of the equipment, with T6 being the most stringent (≤85°C).
Different components may have different temperature classes depending on their location and operating temperature.
5.2 Identification and Marking of Explosion-Proof Products
Products suitable for use in potentially explosive atmospheres carry special markings that must correspond to the EC Type Examination Certificate:
Typical Marking Example:
VIBRO-METER S.A.
Type: CA 134
Serial No.: ...
Year of Construction: ...
II 1G (Equipment Group: II=Non-mining, 1=Category 1)
EEx ia IIC T6 to T1 (Protection Type: ia Intrinsic Safety, Gas Group IIC, Temperature Class T6 to T1)
LCIE 02 ATEX 6110 X (Certificate Number)
The "X" marking indicates the equipment is subject to special conditions for safe use, detailed in the "Schedule" section of the certificate.
5.3 Requirements for Explosion-Proof System Composition
An intrinsically safe system consists of three parts, and the entire combination must be certified as compatible:
Field Device: Sensors, converters, etc., installed in the hazardous area.
Associated Apparatus: Galvanic Separation Units, etc., installed in the safe area.
Connecting Cable: Its parameters (capacitance, inductance) must be within the system's allowable limits.
System Compatibility Verification:
Field device parameters: Ui, Ii, Ci, Li.
Associated apparatus parameters: Uo, Io, Co, Lo.
Cable distributed parameters (capacitance, inductance per unit length).
Must satisfy: Ui ≥ Uo, Ii ≥ Io, Ci + Ccable ≤ Co, Li + Lcable ≤ Lo.
5.4 Special Installation Requirements for Explosive Atmospheres
Equipment Matching: Can only be connected to certified intrinsically safe apparatus.
Cable Parameter Control: Cable distributed capacitance and inductance must be included in system calculations.
Grounding and Equipotential Bonding: Housings must be connected to an equipotential bonding system.
No Unauthorized Modifications: Any modification without the manufacturer's written permission invalidates the certification and warranty.
Maintenance Restrictions: Explosion-proof equipment must not be repaired on-site; it must be returned to an authorized service center.
Chapter 6: Accessories and Auxiliary Mounting Components
6.1 Mounting Studs
When direct mounting onto a machined surface is not possible, dedicated mounting studs are used:
TA 102 Stud (Figure 8-1):
TA 104 Stud (Figure 8-2):
For CA 134, CA 135, CA 136, CE 134, and CE 136.
90° mounting angle.
Improves mounting quality on uneven surfaces.
TA 106 Stud (Figure 8-3):
6.2 Insulating Supports
6.2.1 Electrically Insulating Support (TA 101) (Figure 8-4)
For CA 201 and CE 310.
Includes insulating bushings and an insulating plate.
Prevents ground loops and electrical interference.
Requires insulating bolts and washers for installation.
6.2.2 Thermally Insulating Support (TA 105) (Figure 8-5)
For CA 135, CA 136, and CE 136.
Maximum temperature resistance: 300°C.
5mm thick insulating plate with three equally spaced bore holes.
Reduces heat conduction from hot equipment to the sensor.
6.3 Cable Protection Accessories
Stainless Steel Braided Sheath (BOA):
Provides mechanical protection and limited flexibility.
Heat and corrosion resistant.
Pre-installed on models with integral cables.
KS 106 Flexible Conduit:
Galvanized steel or stainless steel material.
Provides additional mechanical protection for transmission cables.
Particularly useful in areas prone to impact or abrasion.
Mounting Clips:
For cables/conduits with a diameter of approximately 8 mm.
Fixed at 100-200 mm intervals.
Prevents cable vibration and chafing.
Chapter 7: Maintenance, Troubleshooting, and Technical Support
7.1 Basic Maintenance Principles
Vibro-Meter piezoelectric accelerometer systems are designed as maintenance-free devices, but appropriate inspections can extend service life:
7.1.1 Periodic Inspection Checklist
Visual Inspection: Check for physical damage, corrosion.
Cable Inspection: Check sheath integrity, connection security.
Mounting Inspection: Check bolt tightness, for any loosening.
Signal Inspection: Check baseline noise, sensitivity changes.
7.1.2 Cleaning Recommendations
Wipe housings with a soft cloth.
Avoid corrosive cleaning agents.
Use dedicated electronic contact cleaner for connectors.
7.1.3 Special Requirements for Explosion-Proof Equipment
Any maintenance must comply with the EC Type Examination Certificate requirements.
Explosion-proof equipment must not be modified or repaired on-site.
Only original spare parts must be used.
7.2 Troubleshooting Guide
7.2.1 Common Fault Symptoms and Possible Causes
| Symptom | Possible Cause | Troubleshooting Steps |
| No Signal Output | Power Fault | Check GSI power, loop current. |
| Cable Break | Check continuity, connectors. |
| Sensor Failure | Replace for testing. |
| High Signal Noise | Poor Grounding | Check ground connections, shield continuity. |
| EMI | Distance from interference sources, check cable routing. |
| Cable Triboelectric Noise | Re-secure cable, avoid chafing. |
| Signal Drift | Temperature Effect | Check if ambient temperature exceeds limits. |
| Sensor Failure | Replace for testing. |
| Contaminated Connector | Clean connector contacts. |
| Sensitivity Change | Sensor Overload | Check if vibration exceeds measurement range. |
| Loose Mounting | Re-tighten mounting bolts. |
| Sensor Aging | Check via calibration. |
7.2.2 Basic Test Methods
Resistance Check: Disconnect and measure resistance across sensor terminals (typically >1 MΩ).
Insulation Check: Measure insulation resistance between sensor and ground (should be >100 MΩ).
Functional Test: Tap the sensor lightly and observe signal response.
Substitution Test: Replace with a known-good sensor for testing.
7.3 Calibration and Re-certification
7.3.1 Recommended Calibration Intervals
General Applications: Every 24 months.
Critical Applications: Every 12 months.
Extreme Environments: Every 6 months or less.
7.3.2 Calibration Items
Sensitivity (pC/g or mV/g).
Frequency Response (amplitude and phase).
Linearity.
Transverse Sensitivity.
Temperature Response (optional).
7.3.3 Re-certification for Explosion-Proof Equipment
Required after any repair.
Must be performed only by authorized service centers.
Updates the explosion-proof certificate and markings.
Chapter 8: Application Fields and Selection Examples
8.1 Typical Industrial Application Areas
Manual Section 1.2 lists the wide application areas of piezoelectric accelerometers:
8.1.1 Rotating Machinery / Driving Elements
Electric Motors: Induction, synchronous, DC motors.
Combustion Engines: Diesel, gas engines.
Gas Turbines: Aircraft-derived, heavy-duty industrial.
Steam Turbines: For power generation, drives.
Hydraulic Turbines: Francis, Kaplan, Pelton types.
Gearboxes: Parallel shaft, planetary, worm gear.
8.1.2 Rotating Machinery / Driven Elements
Fans: Centrifugal, axial.
Pumps: Centrifugal, positive displacement, reciprocating.
Compressors: Centrifugal, axial, screw, reciprocating.
Generators: Turbo-generators, hydro-generators, diesel generators.
8.1.3 Other Applications
Structural Vibration Monitoring: Bridges, buildings, towers.
Loose Parts Monitoring in Rotating Machines: Detecting loose blades, bolts, etc.
Process Machinery Monitoring: Extruders, crushers, screens.
8.2 Selection Example Analysis
Example 1: Vibration Monitoring in High-Temperature Zone of a Gas Turbine
Environmental Characteristics: High temperature (up to 600°C), potentially explosive (fuel leak risk).
Selection Recommendation: CA 905 (withstands 620°C) or CA 134 Ex i version (withstands 450°C).
Configuration: Separate charge converter installed in a cooler area, using mineral-insulated cables.
Certification Requirements: EEx ia IIC T1-T6, compliant with ATEX and IECEx.
Example 2: Vibration Monitoring on a Refrigeration Compressor
Environmental Characteristics: Low temperature (down to -50°C), potentially flammable refrigerant present.
Selection Recommendation: CA 134 cryogenic version (withstands -200°C to +450°C).
Configuration: Integral cable to minimize connection points in the cold zone.
Considerations: Prevent cable condensation, icing.
Example 3: Pump Set Monitoring on an Offshore Platform
Environmental Characteristics: High corrosion, high humidity, space constraints, explosion-proof requirements.
Selection Recommendation: CE 310 Ex i version (incorporated conditioning, compact structure).
Configuration: Stainless steel housing, IP65 protection, connection via junction box.
Mounting: Use TA 102 stud for easier mounting on uneven surfaces.
Example 4: Online Monitoring of a Critical Gearbox
Requirements: High-frequency response (to monitor gear mesh frequencies), high reliability.
Selection Recommendation: CA 201 (shear design, insensitive to base strain).
Mounting: Threaded mounting for optimal frequency response.
Signal Processing: Charge converter with low-pass filter to suppress high-frequency noise.
8.3 Vibration Parameter Conversion and Nomogram Use
Manual Appendix A provides Acceleration-Velocity-Displacement Nomograms for vibration parameter conversion:
Nomogram L 1347 (Metric Units):
X-axis: Vibration Frequency (Hz).
Left Y-axis: Displacement Amplitude (peak-to-peak, μm).
Middle Y-axis: Velocity Amplitude (peak, mm/s).
Right Y-axis: Acceleration Amplitude (peak, g).
Usage Example:
Given: Acceleration 1 g peak, Frequency 157 Hz.
From the chart: Velocity 10 mm/s peak, Displacement 20 μm peak-to-peak.
Engineering Significance:
Displacement: Reflects low-frequency, large-mass vibrations, concerns gaps and deformation.
Velocity: Internationally accepted vibration severity indicator, reflects vibration energy.
Acceleration: Reflects shock and high-frequency vibrations, concerns fatigue and impact loads.
Chapter 9: Standards Compliance and Certification Systems
9.1 International Standards Compliance
Vibro-Meter products comply with numerous international standards:
9.1.1 Vibration Sensor Standards
ISO 5348: Guidelines for the mounting of vibration sensors.
ISO 10816: General guidelines for the evaluation of machine vibration.
API 670: Machinery Protection Systems (for petroleum and chemical industries).
9.1.2 Electrical Safety Standards
EN 61010-1: Safety requirements for electrical equipment for measurement, control, and laboratory use.
EN 50014: Electrical apparatus for potentially explosive atmospheres - General requirements.
EN 50020: Electrical apparatus for potentially explosive atmospheres - Intrinsic safety "i".
9.2 Overview of Certification Systems
9.2.1 ATEX Certification (Europe)
Directives: 94/9/EC (Equipment Directive), 1999/92/EC (Workplace Directive).
Notified Bodies: LCIE (France), KEMA (Netherlands).
Certificate Example: LCIE 02 ATEX 6110 X (for CA 134/136/160/201).
9.2.2 IECEx Certification (International)
Based on IEC 60079 series standards.
International mutual recognition, reducing duplicate certification.
9.2.3 cCSAus Certification (North America)
Combines CSA (Canada) and UL (USA) requirements.
Certificate Example: 1636188 (for CA 134).
Compliant Standards: CSA C22.2 No. 157, UL 913, UL 61010C-1.
9.2.4 Other Regional Certifications
9.3 Interpretation of Certificate Parameters
Using certificate LCIE 02 ATEX 6110 X as an example:
Apparatus Parameters:
Models: CA 134/CA 136/CA 160/CA 201.
Protection Type: Intrinsic Safety "ia".
Gas Group: IIC (highest level).
Temperature Class: T6 to T1 (CA 134), T6 to T2 (others).
Electrical Parameters (Sensor only):
Ci: Internal capacitance (0.3 nF for CA 134, 8 nF for CA 136).
Li: Internal inductance (0, negligible).
Associated Apparatus Limitations:
Chapter 10: Technology Trends and Future Outlook
10.1 Evolution of Piezoelectric Sensing Technology
10.1.1 Advances in Material Science
New Piezoelectric Ceramics: Higher sensitivity, wider temperature ranges.
Single Crystal Piezoelectric Materials: Improved linearity and stability.
Composite Materials: Flexible piezoelectric sensors for curved surface mounting.
10.1.2 Integration with MEMS Technology
MEMS Accelerometers: Lower cost, smaller size.
Hybrid Systems: Combining piezoelectric and MEMS for balanced performance and cost.
Multi-axis Integration: Three-axis accelerometers in a single package.
10.2 Trends Towards Intelligence and Networking
10.2.1 Features of Smart Sensors
Built-in Diagnostics: Self-test, self-calibration, fault prediction.
Digital Output: Direct digital interfaces (IEPE, digital buses).
Parameter Storage: Serial number, calibration data, configuration parameters stored within the sensor.
10.2.2 Integration with Industrial IoT
Wireless Transmission: Battery-powered wireless sensor networks.
Edge Computing: Preliminary signal processing at the sensor node.
Cloud Platform Integration: Vibration data uploaded to the cloud for big data analysis and machine learning.
10.3 Evolution of Maintenance Strategies
10.3.1 From Preventive to Predictive Maintenance
Condition-Based Maintenance (CBM): Scheduling maintenance based on actual condition.
Predictive Maintenance (PdM): Based on trend analysis and failure prediction.
Prognostic Maintenance (PM): Detection of early failure indications.
10.3.2 Application of Digital Twin Technology
Virtual Model: Creating a digital twin of the equipment.
Real-time Synchronization: Sensor data updating the digital model in real-time.
Simulation and Prediction: Performing fault simulation and life prediction on the digital model.
10.4 Sustainability and Environmental Considerations
10.4.1 Long-Life Design
Extended Calibration Intervals: More stable sensor designs.
Repairability: Modular design for easier repair and upgrades.
Material Selection: Environmentally friendly, recyclable materials.
10.4.2 Energy Efficiency
10.4.3 Adaptability to Extreme Environments
Deeper Subsea Applications: Higher pressure ratings.
Space Applications: Radiation-hardened, ultra-high vacuum compatible.
Geothermal Applications: Higher temperatures, corrosive environments.
Conclusion: Building a Reliable Industrial Vibration Monitoring System
Vibro-Meter's piezoelectric accelerometer systems represent a high-standard solution in the field of industrial vibration monitoring. By deeply understanding their technical principles, correctly selecting models, following standardized installation and maintenance procedures, and combining them with appropriate signal processing and data analysis, a reliable and efficient equipment health monitoring system can be built.
Key elements for the successful implementation of a vibration monitoring project are summarized as follows:
Systematic Planning: Start from the measurement objectives, comprehensively considering environmental, technical, safety, and economic factors.
Correct Selection: Choose the appropriate sensor type based on temperature, frequency, environmental conditions, and certification requirements.
Standardized Installation: Strictly follow manual requirements for surface preparation, mounting, and cable routing.
Strict Certification Compliance: Ensure overall system certification compliance in potentially explosive atmospheres.
Continuous Maintenance: Establish regular inspection, calibration, and documentation update procedures.
Data Analysis: Transform raw vibration data into actionable insights about equipment health.
Personnel Training: Ensure operators and maintenance personnel possess the necessary technical and safety knowledge.
With the development of Industry 4.0 and smart manufacturing, vibration monitoring technology is evolving from isolated protection systems towards integrated intelligent sensing nodes. Professional manufacturers like Vibro-Meter, through continuous technological innovation, are driving this field towards higher reliability, greater intelligence, and broader applicability, providing a solid foundation for the safe, efficient, and sustainable operation of industrial equipment worldwide.
This article, based on a systematic analysis of the Vibro-Meter technical manual, aims to provide a comprehensive technical reference for engineers and technicians. In practical applications, always refer to the latest version of the manual, data sheets, and technical bulletins, and consult the manufacturer's technical support to ensure the optimization and safety of system design, installation, and operation.
Reference Manual: Vibro-Meter CAxxx/CExxx Piezoelectric Accelerometer Instruction Manual
