The CE620 444‑620‑000‑011‑A2‑B500 is a premium, high‑sensitivity piezoelectric accelerometer with integrated electronics from Meggitt’s distinguished vibro‑meter® product line, specifically engineered for general‑purpose vibration monitoring in potentially explosive atmospheres where intrinsic safety is required and low‑amplitude signals must be captured with exceptional resolution. This Ex‑certified version, featuring a sensitivity of 500 mV/g, is designed for installation in hazardous areas classified as Zone 0, 1, or 2 (gas) and Zone 20, 21, or 22 (dust), offering intrinsic safety protection (Ex ia) according to the most stringent international standards. The sensor delivers a voltage output signal proportional to acceleration, with a dynamic range of ±16 g, making it ideal for monitoring low‑level vibrations on large, slow‑speed machinery, precision equipment, and structures in oil refineries, chemical plants, gas terminals, and other explosive environments where high sensitivity is paramount.
The CE620 444‑620‑000‑011‑A2‑B500 incorporates a piezoelectric sensing element with built‑in integrated electronics (IEPE – Integrated Electronics Piezo Electric) that convert the charge generated by the element into a low‑impedance voltage signal. This signal is transmitted over a standard 2‑wire shielded cable, which simultaneously provides power to the sensor and carries the AC vibration signal superimposed on a DC bias voltage. The sensor requires a constant current power supply (0.5 to 8 mA) and operates from an 18 to 30 VDC supply, making it compatible with most industrial monitoring systems. The integrated electronics are ground‑isolated from the case, ensuring excellent noise immunity and stable bias voltage performance, even in electrically noisy environments.
The CE620 444‑620‑000‑011‑A2‑B500 is housed in a rugged, hermetically sealed stainless‑steel case with an IP67 protection rating, providing full protection against dust, water, and other contaminants. Its compact design and versatile mounting options (with supplied adaptor studs for M8×1.25, M8×1, and 1/4‑28UNF threads) enable easy installation on a wide range of machinery surfaces. The sensor features a 2‑pin MIL‑C/DTL‑5015 type connector, which mates with a variety of cable assemblies suitable for hazardous areas (with appropriate Ex certification and current limiting barriers).
The Ex version (option A2) is certified for intrinsic safety with a reduced temperature range of –55 °C to 115 °C, compared to the standard version’s 140 °C upper limit, to meet the thermal constraints of the Ex ia protection method. The sensor carries ATEX (Baseefa 16 ATEX 0027 X) and IECEx (IECEx BAS 16.0030X) certifications for Ex ia IIC T4 Ga and Ex ia IIIC T135°C Da, making it suitable for use in gas groups IIC (including hydrogen, acetylene) and dust groups IIIC (conductive dusts). North American CCSAus certification is pending, ensuring future compliance for installations in the USA and Canada.
With a frequency response of 2 Hz to 10 kHz (±5 %) and a nominal resonant frequency of 18 kHz, the CE620 444‑620‑000‑011‑A2‑B500 captures both low‑frequency machinery dynamics and high‑frequency gearmesh and blade‑pass signatures. Its temperature sensitivity deviation is ±5 % over the –55 to 115 °C range, ensuring reliable performance in harsh thermal environments. The 500 mV/g sensitivity provides a significantly higher output for low‑amplitude signals compared to the 100 mV/g version, making it ideal for detecting subtle changes in bearing condition, imbalance, and structural resonances in hazardous areas.
This product introduction provides a comprehensive description of the CE620 444‑620‑000‑011‑A2‑B500, including key features, applications, detailed technical specifications in tabular form, installation guidelines, ordering information, and available accessories. All information is derived from the official Meggitt data sheet (CE620 old version, 2020) and reflects the company’s commitment to engineering excellence and safety in extreme environments.
Key Features and Benefits
Ex Certified for Hazardous Areas – The CE620 444‑620‑000‑011‑A2‑B500 is approved for use in potentially explosive atmospheres with ATEX (Baseefa 16 ATEX 0027 X) and IECEx (IECEx BAS 16.0030X) certifications for Ex ia IIC T4 Ga (gas zones 0, 1, 2) and Ex ia IIIC T135°C Da (dust zones 20, 21, 22). CCSAus certification is pending, ensuring future compliance for North American installations.
High Sensitivity for Low‑Level Measurements – With a sensitivity of 500 mV/g ±5 %, the sensor provides a strong output signal for low‑amplitude vibrations (e.g., bearing wear, structural resonances), minimising the need for external amplification and improving signal‑to‑noise ratio. This is particularly valuable in hazardous areas where measurement accuracy is critical for early fault detection.
Integrated Electronics (IEPE) – The built‑in charge‑to‑voltage converter eliminates the need for an external charge amplifier, providing a low‑impedance voltage output compatible with standard data acquisition systems. The 2‑wire interface simplifies cabling and reduces installation costs, while the intrinsic safety barriers ensure safe operation in explosive atmospheres.
Limited Dynamic Range Optimised for Sensitivity – The dynamic range of ±16 g (for the 500 mV/g version) is perfectly matched to low‑amplitude monitoring applications, ensuring that the sensor operates within its linear range for most condition monitoring scenarios in hazardous areas, while providing excellent resolution.
Excellent Frequency Response – A flat response of ±5 % from 2 Hz to 10 kHz, combined with a nominal resonant frequency of 18 kHz, enables accurate measurement of slow‑speed machinery, high‑speed turbines, and gearbox vibrations.
Ground‑Isolated Case – The sensor’s base and case are electrically isolated from the signal ground, preventing ground loops and ensuring clean signal transmission in electrically noisy industrial environments. This feature is particularly beneficial in Ex installations where multiple earth points may exist.
Wide Operating Temperature Range (Ex version) – The CE620 444‑620‑000‑011‑A2‑B500 operates continuously from –55 °C to 115 °C, with minimal temperature‑induced sensitivity deviation (±5 % typical), making it suitable for applications ranging from cold outdoor environments to moderately hot process areas.
Robust IP67 Protection – The hermetically sealed stainless‑steel housing provides full protection against dust, water immersion, and a wide range of industrial contaminants, ensuring long‑term reliability in harsh environments.
Low Electrical Noise – Residual electrical noise is only 0.1 mg (maximum), ensuring high signal‑to‑noise ratio for precise low‑level vibration measurements. Electromagnetic sensitivity is exceptionally low at 50 μg/gauss.
Reversed Polarity Protection – The sensor is protected against accidental reversed power connections, preventing damage during installation or maintenance.
Easy Mounting – Supplied with three adapter studs (M8×1.25, M8×1, and 1/4‑28UNF), the sensor can be mounted directly onto a variety of thread sizes without additional adaptors. The external thread (1/4‑28UNEF‑2A or 5/8‑24UNEF‑2A) ensures secure attachment.
Factory Calibration – Each unit is dynamically calibrated at the factory; no subsequent calibration is required under normal use, reducing maintenance costs.
CE Marked and RoHS Compliant – The CE620 444‑620‑000‑011‑A2‑B500 meets European Union environmental and safety standards, ensuring global acceptance.
Applications
The CE620 444‑620‑000‑011‑A2‑B500 is ideally suited for vibration monitoring in hazardous areas (gas and dust explosive atmospheres) where high sensitivity is required for low‑amplitude signals, including:
Large Slow‑Speed Machinery in Hazardous Areas – Monitoring of bearings, journals, and structural vibrations on large turbines, hydroelectric generators, wind turbine main shafts, and gearboxes in oil refineries, gas processing plants, and offshore platforms where flammable gases are present and vibration levels are inherently low.
Precision Equipment in Explosive Environments – Vibration analysis of machine tools, spindles, and high‑speed milling machines in chemical or pharmaceutical plants where solvent vapours or combustible dusts exist, to detect tool wear, imbalance, and bearing defects at early stages.
Structural Health Monitoring – Measurement of low‑level vibrations on bridges, building foundations, and heavy structures in hazardous zones to assess dynamic characteristics and detect fatigue cracks.
Pumps and Compressors – Monitoring of low‑frequency pulsations and bearing wear in centrifugal pumps, reciprocating compressors, and vacuum pumps in gas terminals and refineries where sensitivity is crucial.
Test and Measurement in Ex Zones – Laboratory and field testing for modal analysis, shock response, and vibration qualification in hazardous areas where high output is beneficial.
Marine and Offshore – Propulsion systems, deck machinery, and cargo pumps on tankers and FPSO vessels operating in hazardous zone classifications, where low‑level vibrations must be captured reliably.
Wastewater and Biogas – Monitoring of pumps, blowers, and mixers in biogas plants and wastewater treatment facilities where methane or hydrogen sulphide may be present, and low‑amplitude signals indicate early wear.
General Industrial Condition Monitoring in Hazardous Areas – Any rotating or reciprocating machinery in factories, power plants, and processing facilities where low‑level vibration signals must be reliably detected for predictive maintenance.
Detailed Description of the Ex Intrinsic Safety Version (444‑620‑000‑011‑A2‑B500)
The CE620 444‑620‑000‑011‑A2‑B500 is the Ex‑certified variant of the CE620 family, featuring a high sensitivity of 500 mV/g and a reduced temperature range of –55 °C to 115 °C (order option A2) to comply with the thermal limitations of intrinsic safety (Ex ia). It is designed for general‑purpose vibration monitoring in hazardous areas where explosive gas or dust atmospheres may be present and where low‑amplitude signals must be accurately captured. The sensor is built around a piezoelectric sensing element that generates an electrical charge proportional to acceleration. The integrated electronics package, housed within the sensor casing, converts this charge into a low‑impedance voltage signal, which is transmitted over a two‑wire shielded cable.
The sensor’s output is a voltage signal consisting of a DC bias voltage (nominal 12 V) and an AC vibration component superimposed on it. The bias voltage provides a reference level and also powers the internal electronics. The sensor requires an external constant current power supply (IEPE conditioner) that provides a current source between 0.5 and 8 mA (typically 2 to 4 mA) and a DC voltage of 18 to 30 V. The current source is connected in series with the signal line, and the AC vibration signal is measured across a load resistor in the monitoring system, typically extracting the AC component via a high‑pass filter.
For Ex ia installations, the sensor must be connected through an approved intrinsically safe barrier or galvanic isolation unit that limits the voltage, current, and energy to levels that cannot ignite the explosive atmosphere. The barrier must comply with the parameters specified in the Ex certificate (Baseefa 16 ATEX 0027 X and IECEx BAS 16.0030X). The sensor itself is designed with internal protection to ensure that under fault conditions, the energy remains below ignition thresholds.
The ground‑isolated design ensures that the sensor case and mounting base are electrically isolated from the signal ground. This is critical in industrial settings where multiple earth points can create ground loops, leading to measurement errors and noise. The isolation also allows the sensor to be mounted directly on grounded metal structures without affecting signal integrity.
The mechanical construction features a hermetically welded stainless‑steel housing that provides IP67 protection against dust, water immersion, and corrosion. The sensor’s connector is a rugged, circular 2‑pin MIL‑C/DTL‑5015 type, which provides a secure, vibration‑resistant interface for cable connections. For Ex applications, the cable assemblies must be selected from those that maintain the intrinsic safety integrity – typically those with appropriate cable capacitance and inductance parameters, and often with a metallic overbraid or protection tube to prevent mechanical damage.
The mounting interface is an external thread – either 1/4‑28UNEF‑2A or 5/8‑24UNEF‑2A, depending on the specific version. The supplied adapter studs allow conversion to common metric threads (M8×1.25 and M8×1) as well as imperial 1/4‑28UNF, providing flexibility for mounting on various machine surfaces. The sensor is designed to be mounted directly to the machine surface using a stud, with a recommended torque to ensure proper coupling and high‑frequency response.
The CE620 444‑620‑000‑011‑A2‑B500 is factory‑calibrated at a reference frequency (typically 100 Hz) and amplitude, with the sensitivity verified to be within ±5 % of the nominal 500 mV/g. The calibration is performed using a known acceleration standard, and no further calibration is required during the sensor’s lifetime under normal operating conditions. However, periodic verification (e.g., every 2‑5 years) is recommended for critical safety‑related applications.
The Ex version (A2) is distinguished from the standard version (A1) by its reduced upper temperature limit (115 °C instead of 140 °C) and its intrinsic safety certification. The sensor carries ATEX and IECEx certifications for both gas and dust environments, covering the most severe gas group IIC (hydrogen, acetylene) and dust group IIIC (conductive dusts). The temperature class T4 (135 °C) ensures that the sensor surface temperature does not exceed 135 °C under normal or fault conditions, making it suitable for atmospheres with ignition temperatures above 135 °C.
The high sensitivity of 500 mV/g is particularly advantageous in hazardous areas where low‑amplitude vibrations (e.g., bearing defects, structural resonances) must be detected early to prevent catastrophic failures. The dynamic range of ±16 g ensures linear operation for most condition monitoring scenarios, while the strong output signal reduces the need for additional amplification and improves measurement accuracy. The sensor’s low noise and excellent electromagnetic immunity further enhance its performance in electrically noisy environments typical of industrial plants.
North American CCSAus certification is pending as of the data sheet revision, but the design is expected to meet the requirements for Class I, Division 1, Groups A‑D, and Class II, Division 1, Groups E‑G, as well as Class I, Zone 0, AEx ia IIC T4 Ga. Users should check the latest Ex product register (PL‑1511) for up‑to‑date certification status.
Installation and Mounting Guidelines
Proper installation is essential to achieve the specified performance and maintain the Ex certification of the CE620 444‑620‑000‑011‑A2‑B500. The following guidelines are based on Meggitt’s recommended practices and the requirements of the applicable Ex certificates:
Mounting Surface Preparation – The mounting surface should be flat, smooth, and clean. Any burrs, paint, or corrosion must be removed to ensure full contact between the sensor base (or adapter stud) and the machine surface. A surface finish of 1.6 µm (63 µin) or better is recommended for optimal high‑frequency response.
Adapter Stud Selection – The sensor is supplied with three adapter studs: one M8×1.25, one M8×1, and one 1/4‑28UNF. Choose the stud that matches the threaded hole in the machine or the mounting block. If using a different thread, optional mounting adaptors (e.g., MA122 with M6 thread) are available.
Torque Application – Screw the chosen stud into the sensor base (using the 1/4‑28UNEF‑2A or 5/8‑24UNEF‑2A thread) and tighten to the recommended torque (typically 7‑10 N·m for the stud, or as specified in the accessories data sheet). Then mount the assembled sensor onto the machine surface, applying the appropriate torque for the machine thread (e.g., 15‑20 N·m for M8). Do not over‑torque, as this may damage the threads or the sensor housing.
Orientation and Alignment – The sensor is sensitive along its principal axis (marked on the housing). Align the sensor such that the principal axis coincides with the direction of the vibration to be measured (axial, radial, or tangential). Refer to the installation manual for detailed orientation diagrams.
Cable Routing and Connector – Ex Requirements – The sensor uses a 2‑pin MIL‑C/DTL‑5015 type connector. For Ex ia installations, the cable assembly must be selected from those certified for use with the sensor (e.g., EC318 with RADOX® cable or EC319 with splashproof protection). The cable must be routed with a minimum bend radius to avoid stress and internal damage. The cable shield must be grounded at one end (typically at the control panel) to avoid electromagnetic interference, but care must be taken not to create ground loops. All cable glands and junction boxes in the hazardous area must be Ex‑certified and installed according to local regulations.
Electrical Connections – Intrinsic Safety – The sensor must be connected through an approved intrinsically safe barrier or galvanic isolation unit (e.g., GSI127) that limits the voltage, current, and power to the values specified in the Ex certificate (Baseefa 16 ATEX 0027 X / IECEx BAS 16.0030X). The barrier must be located in the safe area or be certified for installation in the hazardous area. The supply voltage must be within 18 to 30 VDC, and the current must be between 0.5 and 8 mA. The signal is measured as the AC voltage on the bias level (typically 12 V) via a decoupling capacitor in the monitoring system. Ensure the monitoring system provides the appropriate high‑pass filtering (usually with a cutoff frequency of 0.5 to 1 Hz for the sensor’s specified response). The cable capacitance and inductance must be within the permissible limits to avoid spark ignition.
Grounding – The sensor’s base is isolated from the signal ground, so the mounting surface can be at any potential without affecting the signal. However, the cable shield should be grounded at one end (usually at the monitoring system) to minimise electromagnetic interference. Follow the grounding practices recommended in the system’s installation manual and the Ex certificate requirements.
Thermal Considerations – Ex Temperature Class – The sensor is rated for continuous operation up to 115 °C, which ensures the surface temperature does not exceed the T4 rating (135 °C) even under fault conditions. If the mounting surface exceeds 115 °C, use a thermal insulating adaptor or mount the sensor remotely with an extension rod. The connector and cable must also be rated for the expected temperature; for high‑temperature Ex applications, use cables with suitable insulation (e.g., RADOX® 125 or metallic overbraid).
Protection from Physical Damage – In harsh environments, protect the sensor and cable from impacts, abrasion, and chemical attack. Use protective covers or conduits if necessary. The IP67 rating ensures the sensor is dust‑tight and protected against water immersion, but mechanical protection is still recommended.
Hazardous Area Precautions – Installation must be carried out by competent personnel trained in Ex practices. All wiring, cable glands, and junction boxes must comply with local regulations and the relevant Ex standards. The sensor and its associated cables must be protected from mechanical damage and chemical attack. Regular inspection and maintenance as per the plant’s safety procedures are mandatory. The Ex certificate includes special conditions for safe use (e.g., the sensor must be used with a certified barrier, and the cable must be secured to avoid strain).
Commissioning – Before energising, verify that all connections are correct, the Ex barrier is properly installed, and the cable routing does not subject the connector to excessive strain. Perform a functional test using a known vibration source to confirm sensitivity and output current (bias voltage). Record the bias voltage and signal levels for future reference.
Commissioning and Verification
After installation, the CE620 444‑620‑000‑011‑A2‑B500 should be verified using a known vibration source (e.g., a portable shaker or a reference accelerometer) or by comparing with a known good sensor. The bias voltage should be measured to confirm it is approximately 12 V (within ±1 V). The AC signal should be checked for proper sensitivity; a known acceleration level (e.g., 1 g at 80 Hz) should produce the expected output (500 mV/g). Also verify that the signal is free from excessive noise and that the low‑frequency cutoff is appropriate for the intended measurement. In Ex installations, verify that the barrier is operating within its specified parameters. For long‑term monitoring, regular system checks during routine maintenance are recommended.
Accessories
A range of accessories is available to complement the CE620 444‑620‑000‑011‑A2‑B500, with specific attention to Ex‑compatible cables and barriers:
ITEM | TYPE | DESCRIPTION | PART NUMBER (PNR) |
Cable Assemblies (2‑pin MIL‑C/DTL‑5015) – For Ex use, select cables that maintain intrinsic safety and are suitable for the hazardous area. | EC318 | Standard version with RADOX® 125 2‑wire cable (suitable for Ex with proper barrier) | 922‑318‑000‑002 |
| EC318 | Standard version with RADOX® 125 cable and protection tube | 922‑318‑000‑403 |
| EC319 | Splashproof version with RADOX® 125 cable | 922‑319‑000‑002 |
| EC319 | Splashproof version with RADOX® 125 cable and sealed protection tube (leaktight) | 922‑319‑000‑103 |
| EC602, EC612 also available but for non‑Ex or less demanding environments; for Ex, consult Meggitt for approved cable types | | |
Adapter Studs (supplied) | – | M8×1.25, M8×1, and 1/4‑28UNF (one each) | Included |
Mounting Adaptors (optional) | MA122_012 | 1/4‑28UNF‑2A to M6, with conic base | 809‑122‑000‑012 |
| MA122_021 | 1/4‑28UNF‑2A to M6, with conic base (insulating stud) | 809‑122‑000‑021 |
Galvanic Separation Units | GSI127 | Provides galvanic isolation and intrinsic safety barrier for Ex ia installations; must be used with this sensor in hazardous areas | Refer to separate data sheet |
Note: Cable length must be specified when ordering any cable assembly. For Ex installations, ensure the cable assembly and connector are certified for the intended hazardous area and that the total loop parameters (capacitance, inductance) remain within the limits specified in the Ex certificate. The GSI127 barrier is highly recommended for Ex ia applications to provide safe separation.
Disposal and Environmental Compliance
At the end of its service life, the CE620 444‑620‑000‑011‑A2‑B500 must be disposed of in accordance with local environmental regulations. The sensor contains stainless steel, electronic components, and piezoelectric materials. In the European Union, the Waste Electrical and Electronic Equipment (WEEE) Directive applies – separate collection and recycling are mandatory. Meggitt supports environmentally responsible disposal and can provide guidance on proper recycling channels.
