Vibro-Meter CA202 144-202-000-216 Piezoelectric Accelerometer

The CA202 piezoelectric accelerometer is an outstanding industrial-grade vibration monitoring sensor from Meggitt Sensing Systems' vibro-meter series, designed for high-precision, highly reliable long-term vibration measurement in harsh but non-explosive industrial environments. This report details model 144-202-000-216, the Standard Industrial Version equipped with a 6-meter integral cable. This model lacks explosion-proof certification and is suitable for a wide range of industrial sectors where potentially explosive atmospheres are absent, such as conventional thermal and hydroelectric power plants, general manufacturing production lines, large commercial HVAC systems, municipal water supply facilities, and R&D laboratories. It represents the ideal balance point between pursuing top-tier performance and long-term reliability while optimizing system integration complexity and total cost of ownership.

Adhering to the classic design philosophy of the CA202 series, the sensor's core employs a shear-mode polycrystalline piezoelectric sensing element paired with a fully electrically isolated internal case architecture. This ensures exceptional signal symmetry, extremely low transverse sensitivity, and high common-mode interference rejection. Its structural essence lies in the seamless integration of the high-strength austenitic stainless steel sensor housing with a flexible, high-temperature-resistant stainless steel armored protection hose via fully hermetic welding. This creates a robust, monolithic measurement unit from the sensing head to the cable exit. This connector-less design fundamentally eliminates the risk of failure at connection points due to vibration, thermal cycling, or chemical corrosion, enabling it to fearlessly handle common industrial challenges like humidity, condensation, oil, and dust, ensuring long-term signal output stability and purity.

As a key sensing element in modern industrial predictive maintenance systems, the CA202-216 works in synergy with charge amplifiers (e.g., IPC704/705), data acquisition systems, and intelligent analysis platforms (e.g., VM600) within the vibro-meter ecosystem. This forms a complete value chain from physical signal sensing and anti-interference transmission to intelligent diagnostics. Its 6-meter cable length provides significant flexibility for engineering installation, meeting the distance requirements from most equipment measurement points to nearby junction boxes or amplifier mounting locations while avoiding the complexity and cost increase associated with overly long cables. It is a foundational choice for building efficient and reliable condition monitoring networks.

2. Core Advantages and Value Proposition

1. Industrial-Grade Ruggedness & Exceptional Environmental Endurance:

• Extremely Wide Operating Temperature Window: The sensing head can operate continuously within an extreme temperature range of -55°C to +260°C, while the integral cable can withstand environments from -55°C to +200°C. This allows it to be mounted directly on gas turbine casings, high-temperature pump bodies, fans in cold outdoor environments, etc., adapting to global deployment from the Arctic Circle to the equator, from high-temperature metallurgical workshops to refrigerated storage facilities.

• Ultimate Protection via Full Welded Hermetic Seal: The welded, integrated design of sensor and cable provides protection levels exceeding those of traditional plug-and-play connectors. It does not rely on any rubber gaskets, completely eliminating media ingress issues caused by gasket aging or wear. It performs particularly reliably under high-pressure water washdown, high humidity, or corrosive atmospheres, significantly reducing failure rates and maintenance costs over its lifecycle.

2. Accurate, Stable Top-Tier Measurement Performance:

• High Output Sensitivity & Wide Flat Frequency Response: A nominal sensitivity of 100 pC/g provides a high signal-to-noise-ratio foundation for detecting early-stage, weak mechanical fault signatures. The flat frequency response from 0.5 Hz to 6 kHz (±5%) enables it to accurately capture both the fundamental vibrations of large, slow-rotating machinery (e.g., cement mills) and the high-frequency dynamic signals of high-speed precision equipment (e.g., high-speed compressors, gearboxes).

• Excellent Dynamic Range & Linearity: A linear measurement range up to 400g ensures that the sensor output remains highly linear (error < ±1%) even under operating conditions with transient shocks or large-amplitude vibrations, truly reproducing vibration intensity. A high resonant frequency (>22kHz) guarantees excellent phase response and amplitude fidelity within its operating bandwidth.

• Powerful Anti-Interference Core: The built-in symmetrical differential sensing element and high insulation resistance (≥10^9 Ω) form a natural barrier against ground loop interference and on-site electromagnetic noise, ensuring "clean" raw signal output even in complex industrial electrical environments.

3. Optimized Economics for Standard Industrial Applications:

• Simplified Systems Engineering: As a non-explosion-proof standard version, the CA202-216 does not require intrinsically safe barriers or complex intrinsic safety system parameter calculations and certifications. It can be integrated more directly and flexibly into standard industrial automation and control systems, significantly reducing the complexity, time, and cost of system design, procurement, and commissioning.

• Flexible 6-Meter Cable Configuration: The 6-meter length is a practice-proven "golden" length, balancing installation freedom with cost control. It allows the charge amplifier to be installed several meters away from the sensor in a safer, more serviceable location, while avoiding concerns about signal attenuation and material waste associated with excessively long cables.

• Global Compliance, Barrier-Free Deployment: The product carries the CE mark, complies with EU EMC and LVD directives, and meets RoHS environmental requirements. This allows its deployment in most global non-explosive industrial markets without additional localized certification adaptations, accelerating project delivery.

4. Plug-and-Play & Ultra-Long Maintenance Intervals:

• Precision from Factory: Each sensor undergoes end-to-end dynamic calibration (5g, 120Hz) under strictly controlled conditions. The accompanying calibration certificate ensures it achieves nominal performance out-of-the-box, greatly simplifying on-site verification processes and reducing reliance on high-precision calibration equipment.

• Nearly "Maintenance-Free" Design: The fully welded hermetic structure and rugged stainless steel materials mean that, after correct installation, the sensor requires almost no preventive maintenance beyond periodic visual inspections, offering users high operational certainty and low total cost of ownership.

  
  

3. Technical Principle & System Integration Framework

The CA202-216 is a classic "separate" piezoelectric accelerometer. Its core sensing process is a pure electromechanical energy conversion:

1. Mechanical Energy Input: External vibration is transmitted through the sensor base to the internal seismic mass.

2. Force-to-Electricity Conversion: The mass applies an alternating shear force to the shear-mode arranged piezoelectric crystal. According to the direct piezoelectric effect, polarization charge proportional to the stress is generated within the crystal, appearing as a high-impedance charge signal (Q) on the electrode surfaces, related to acceleration (a) by: Q = S * a.

3. Signal Transmission: This weak charge signal is transmitted via the 6-meter specially designed low-noise coaxial cable. This cable is designed to minimize the "triboelectric effect" (parasitic noise generated by cable bending or vibration).

The key to system integration is the Charge Amplifier (IPC):

• Signal Conditioning: The charge amplifier provides extremely high input impedance, linearly converting the charge signal to a voltage signal.

• Anti-Interference Transmission: Typically, the amplifier incorporates a V/I conversion circuit, outputting a 2-wire 4-20 mA current loop signal. Current signals are insensitive to transmission line resistance and have strong electromagnetic interference immunity, capable of being transmitted over kilometers via ordinary twisted-pair cable.

• System Powering: The same pair of wires simultaneously provides operating power for the front-end sensor-amplifier loop, enabling "2-wire" installation simplicity.

Finally, the 4-20 mA signal is connected to the control room's data acquisition system (PLC/DCS/I/O card) or dedicated vibration monitor (e.g., VM600), converted to digital values for real-time display, trend analysis, alarming, and fault diagnosis.

The engineering logic behind choosing the 6m Standard CA202-216: It is completely consistent in performance with the top-tier explosion-proof versions but saves considerable cost for the entire monitoring channel by omitting explosion-proof certification and associated intrinsically safe equipment. The 6-meter cable provides sufficient installation flexibility for the vast majority of industrial layouts, representing the "sweet spot" of performance and cost-effectiveness.

4. Typical Application Areas

The CA202-216 Standard Version, due to its exceptional reliability and environmental adaptability, is the preferred choice for vibration monitoring in the following non-explosive industrial sectors:

• Power & Energy (Conventional Areas):

• Coal/Gas-Fired Power Plants: Bearings on turbine-generator sets, feedwater pumps, circulating water pumps, induced draft (ID) fans, forced draft (FD) fans, coal mills.

• Hydroelectric Power Plants: Water turbine guide bearings, thrust bearings, governor oil pressure units.

• Nuclear Power Plant Conventional Island: Main feedwater pumps, condensate pumps, circulating water pumps, various fans.

• Biomass Power Plants: Crushers, conveying equipment.

• General & Heavy Manufacturing:

• Cement Industry: Rotary kiln supporting rollers, grate coolers, large ball mills, crushers.

• Mining & Metallurgy: Ore crushers, ball mills, sintering fans, rolling mills.

• Paper Industry: Paper machine drying cylinders, calenders, winders.

• Shipbuilding & Shipping: Main engines, auxiliary engines, propulsion gearboxes, large pump sets (in non-hazardous areas of engine rooms).

• Infrastructure & Utilities:

• Large Commercial Buildings & Data Centers: Chillers, cooling tower fans, oil/gas-fired boilers.

• Municipal Water Supply & Wastewater Treatment: Intake pumps, delivery pumps, sludge dewatering machines, blowers.

• Rail Transit: Large equipment in station HVAC systems, depot maintenance equipment.

• Research & Development / Quality Testing:

• Automotive, aerospace engine test benches.

• Household appliance, power tool vibration and noise testing.

• Building material and structural component fatigue testing.

  
  

5. Installation, Commissioning & Best Practice Guidelines

5.1 Pre-Installation Planning

1. System Design Confirmation: Confirm compatibility and range settings for the entire measurement chain (sensor -> cable -> amplifier -> acquisition system). Set the correct input capacitance range for the amplifier (must include 6m cable capacitance).

2. Measurement Point Survey: Select locations with the shortest vibration transmission path and best rigidity (typically bearing housings). Ensure the mounting surface is clean, free of rust and paint. Check flatness with a straight edge.

5.2 Mechanical Installation Steps

1. Surface Preparation: If the surface is uneven, it is recommended to machine a small local flat area to a finish of Ra 3.2 μm. Tap M6 threads at screw hole locations to sufficient depth.

2. Mounting the Sensor:

• Apply a medium-strength thread-locking adhesive (e.g., Loctite 243) to the threads of the screws (M6x35).

• Position the sensor, install spring washers, and insert the screws.

• Using a torque wrench, strictly follow a crisscross pattern and tighten in two stages to 15 N·m. Uniform torque is key to ensuring good frequency response characteristics.

5.3 Cable Routing & Handling (6m Cable)

1. Route Planning: Plan a smooth route avoiding sharp bends, sharp edges, hot surfaces (>200°C), and strong EMI sources. Leave about 0.5-1 meter of service slack for future maintenance.

2. Fixing & Protection:

• Use stainless steel clamps to secure the cable to cable trays or equipment structure every 0.8-1.2 meters.

• Within 30-50 cm of the sensor exit, a smooth stress relief loop with a radius greater than 100mm must be formed to prevent equipment vibration from being directly transmitted to the welded joint.

• Route the cable inside flexible metallic conduit (e.g., KS series) or cable trays whenever possible for additional mechanical protection.

3. Grounding: Strictly implement the single-point grounding principle. Connect the cable shield to the amplifier's designated grounding terminal only at the Charge Amplifier (IPC) end. Use a short, thick grounding wire. The sensor mounting base is grounded via the equipment body.

5.4 Electrical Connection & Power-Up Commissioning

1. Connect to Amplifier: Securely connect the CA202 cable's flying leads (typically red positive, white negative/reference, shield) to the terminals labeled "Input" or "Sensor" on the IPC amplifier. Ensure connections are tight.

2. System Connection: Connect the amplifier's output (4-20mA) to the data acquisition device. Confirm the input configuration of the acquisition device matches the current signal.

3. Power-Up & Functional Test:

• After verifying all wiring is correct, power up the system.

• Observe the signal for this channel in the monitoring software. Gently tap the sensor mounting base with a rubber mallet; a clear transient pulse waveform should appear on the screen, indicating the entire path from sensor to software is functional.

4. Baseline Acquisition: After the equipment is running normally and stably, record the vibration values (velocity RMS, acceleration peak, etc.) for each measurement point as a baseline for subsequent trend analysis and alarm setting.

5.5 Safety Warnings

• Prohibited for Hazardous Areas: CA202-216 does not have explosion-proof functionality and is strictly prohibited from installation in areas with explosive atmospheres such as refineries, chemical plants, and natural gas processing plants.

• Do Not Modify Cable: Cutting, splicing, or attempting to lengthen/shorten the original 6-meter cable is strictly prohibited. Any damage will cause sealing failure and performance degradation.

• Professional Operation: Installation and commissioning should be performed by technicians with electrical and mechanical knowledge.

  
  

6. Maintenance, Diagnostics & Lifecycle Support

1. Preventive Maintenance Schedule:

• Monthly/Quarterly Inspection: Visual inspection of the sensor and cable for physical damage, severe corrosion, or loose fasteners. Check the sealing integrity of junction boxes.

• Annual Check: During major equipment overhauls, measure the insulation resistance of the sensor loop to ground; it should remain in the GΩ range. Check the connection at the cable shield grounding point for firmness and absence of corrosion.

2. Fault Diagnosis Process:

• Symptom: No Signal. Steps: 1) Check acquisition system channel and power; 2) Check IPC amplifier indicator/power; 3) Disconnect sensor at amplifier end, measure resistance between the two signal wires with a multimeter (should be open circuit) and resistance to shield (should be >1GΩ).

• Symptom: High Signal Noise, Drift. Steps: 1) Check and ensure grounding is single-point and proper; 2) Check if cable is routed parallel to power cables; 3) Check if sensor mounting is loose; 4) Check amplifier settings (gain, filter).

• Sensor body failure is extremely rare; most issues originate from installation, wiring, or downstream equipment.

3. Calibration Services:

• Recommended Interval: Under normal operating conditions, the recommended calibration interval is 4-5 years. If the sensor experiences severe overload shock or readings show unexplained persistent deviation, calibration should be performed earlier.

• Service Method: Contact a Meggitt authorized service center or a qualified third-party metrology organization to calibrate the sensor and cable as a complete unit. Update the calibration coefficient in the monitoring system after calibration.

4. Global Technical Support Network: Meggitt SA has branch offices and technical support centers worldwide. Users can obtain the latest product manuals, application guides, CAD drawings, and certificate documents via the official website and contact local sales or technical support teams for timely assistance.