CE311 444-311-000-123 Piezoelectric Accelerometer

The CE311 444‑311‑000‑123 is a premium, Ex‑certified piezoelectric accelerometer with integrated electronics from Meggitt’s renowned vibro‑meter® product line, specifically engineered for industrial vibration monitoring in potentially explosive atmospheres where intrinsic safety is required and a moderate cable reach is essential for flexible installation. This Ex‑certified version features a sensitivity of 50 μA/g and is supplied with a factory‑fitted 6‑metre integral cable, protected by a flexible, leak‑tight stainless‑steel hose, terminated with flying leads for direct wiring. This ready‑to‑install configuration eliminates the need for a separate connector at the sensor end, providing a continuous, hermetically sealed connection that is ideal for permanent installations in hazardous areas where protection against cooling fluids, lubricants, water, steam, and other contaminants is critical. The 6‑metre cable length offers greater installation flexibility than the 3‑metre version, allowing the sensor to be mounted at a moderate distance from the monitoring electronics while maintaining signal integrity, making it suitable for larger equipment and installations where the junction box is not immediately adjacent to the sensor. The sensor delivers a current‑modulated output signal proportional to acceleration, with a frequency response from 2 Hz to 8 kHz, making it suitable for a wide range of rotating and reciprocating machinery in oil refineries, chemical plants, gas terminals, offshore platforms, and other hazardous environments where explosive gas or dust may be present.

The CE311 444‑311‑000‑123 is an industry‑standard current‑output IEPE‑type sensor that requires a constant current power supply (5.5 to 7.5 mA) and operates from a 15 to 28 VDC supply. It provides a low‑impedance current‑modulated output that is largely insensitive to cable capacitance and electromagnetic interference, permitting long‑distance signal transmission without degradation. The integrated electronics incorporate internal shielding and are galvanically isolated from the sensor case, ensuring exceptional noise immunity, reduced ground‑loop interference, and stable bias‑voltage performance. 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, in accordance with the parameters specified in the Ex certificates. The updated series (ending in 123) features improved cable capacitance specifications (105 pF/m pole‑to‑pole and 200 pF/m pole‑to‑casing) compared to legacy versions, enhancing compatibility with intrinsically safe barriers and enabling even longer cable runs without signal degradation. The 6‑metre cable adds a nominal capacitance of approximately 0.63 nF pole‑to‑pole and 1.2 nF pole‑to‑casing, which is well within the drive capability of the current loop and the limits of intrinsic safety barriers.

The sensor is housed in a hermetically sealed stainless‑steel case (1.4441) with the integral cable protected by a stainless‑steel hose (1.4541). The sensor and protection tube are hermetically welded to one another, creating a leak‑tight assembly that is impervious to 100 % relative humidity, water, steam, oil, sea‑salt atmospheres, dust, fungus, and sand. This rugged construction ensures decades of reliable operation in the harshest industrial environments, including offshore, chemical, and outdoor installations in hazardous zones.

With a frequency response of –3 dB at 2 Hz, ≤±5 % from 6 Hz to 5 kHz, and ≤±10 % from 5 kHz to 8 kHz, a nominal resonant frequency of 20 kHz, and a dynamic range of 0.004 g to 40 g peak, the CE311 444‑311‑000‑123 captures low‑frequency structural vibrations and high‑frequency gearmesh signatures with good fidelity. Its temperature range of –40 °C to 125 °C, combined with excellent temperature stability (±5 % over the full range), ensures reliable operation in a wide variety of industrial process environments. The sensor carries ATEX (KEMA 04 ATEX 1055) and IECEx (IECEx DEK 15.0029) certifications for Ex ia IIC T6…T3 Ga, as well as CCSAus, KGS, and Ex nA (non‑sparking) and Ex ID (dust ignition protection by enclosure) certifications, making it a versatile and globally compliant choice for gas groups IIC, dust environments, and a wide temperature classification.

This product introduction provides a comprehensive description of the CE311 444‑311‑000‑123, 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 (CE311 updated series, 2022‑2023) and reflects the company’s commitment to engineering excellence and safety in extreme environments.

Key Features and Benefits

Ex Certified for Hazardous Areas – The CE311 444‑311‑000‑123 is approved for use in potentially explosive atmospheres with multiple certifications: ATEX (KEMA 04 ATEX 1055) and IECEx (IECEx DEK 15.0029) for Ex ia IIC T6…T3 Ga (gas zones 0, 1, 2); CCSAus (Class I, Division 1, Groups A, B, C, D; Class I, Zone 0); KGS (Ex ia IIC T6…T3); Ex nA (non‑sparking, Zone 2) per LCIE 09 ATEX 1047 X and IECEx LCI 10.0021X; and Ex ID (dust ignition protection by enclosure, KGS 20‑GA4BO‑0464X). This ensures global compliance for the most severe hazardous areas, including Zone 0 and Zone 20.

Integral Cable with Stainless‑Steel Protection Tube – 6 Metre Length – The factory‑fitted 6‑metre cable (twisted‑pair shielded) with a flexible, leak‑tight stainless‑steel hose provides exceptional mechanical protection, chemical resistance, and durability. The sealed, connector‑less design eliminates potential failure points at the sensor interface, ensuring long‑term signal integrity in harsh and hazardous environments. The 6‑metre length offers greater installation flexibility than shorter versions, allowing the sensor to be placed further from the junction box or monitor without requiring extension cables.

High Sensitivity and Wide Dynamic Range – With a sensitivity of 50 μA/g ±5 % and a dynamic range from 0.004 g to 40 g peak, the sensor captures a broad spectrum of vibration amplitudes, from subtle bearing wear to moderate imbalance events, without saturation.

Extended Frequency Response – The sensor offers a –3 dB point at 2 Hz, a flat response of ±5 % from 6 Hz to 5 kHz, and ±10 % from 5 kHz to 8 kHz, covering low‑frequency structural motions and high‑frequency gearmesh and blade‑pass frequencies.

Low Noise and High Resolution – The residual electrical noise is very low, ensuring clear detection of low‑level vibrations. The internal shielding and isolated electronics further suppress electromagnetic interference, which is particularly important with longer cable runs.

Integrated Electronics (IEPE) – The built‑in charge‑to‑current converter eliminates the need for an external charge amplifier. The 2‑wire interface carries both power and signal, simplifying cabling and reducing system cost. The sensor operates with a constant current of 5.5 to 7.5 mA and a supply voltage of 15 to 28 VDC.

Improved Cable Capacitance Specifications – The updated series features lower cable capacitance (105 pF/m pole‑to‑pole and 200 pF/m pole‑to‑casing) compared to legacy versions, enabling even longer cable runs without signal degradation and improving compatibility with intrinsically safe barriers.

Ground‑Isolated Case with Internal Shield – The sensor case is electrically isolated from the signal ground, preventing ground loops. An internal shield further enhances noise rejection, ensuring clean signal transmission even when mounted on grounded metal structures.

Rugged Hermetically Welded Construction – The hermetically welded stainless‑steel housing and protection tube provide IP protection against dust, water, and a wide range of industrial contaminants. The leak‑tight assembly is impervious to 100 % relative humidity, water, steam, oil, sea‑salt, dust, fungus, and sand, ensuring long‑term reliability.

Wide Operating Temperature Range – The CE311 444‑311‑000‑123 operates continuously from –40 °C to 125 °C, with a temperature sensitivity deviation of ±5 % over the full range, making it suitable for applications ranging from cold outdoor environments to hot process areas.

High Shock Tolerance – With a shock limit of 500 g peak (half‑sine, 1 ms), the sensor withstands severe mechanical transients without damage, ensuring survivability in demanding machinery environments.

Low Base Strain Sensitivity – The base strain sensitivity is only 0.0015 g/με typical, minimising measurement errors caused by mounting surface deformation.

Easy Installation – The integral cable is terminated with flying leads (colour‑coded), allowing direct connection to terminal blocks or junction boxes. The sensor is mounted using four M6 bolts with a recommended torque of 15 N·m, providing secure attachment.

Factory Calibration – Each unit is dynamically calibrated at the factory at 120 Hz and 5 g peak; no subsequent calibration is required under normal use, reducing maintenance costs.

CE Marked, EAC, and RoHS Compliant – The sensor meets European Union EMC, electrical safety, and RoHS requirements, as well as Eurasian Customs Union standards, ensuring global acceptance.

Applications

The CE311 444‑311‑000‑123 is ideally suited for general‑purpose vibration monitoring in hazardous areas (gas, dust) where intrinsic safety is required and a 6‑metre integral cable provides useful reach, including:

• Oil and Gas Industry – Monitoring of compressors, pumps, turbines, and reciprocating machinery in refineries, gas processing plants, and offshore platforms where flammable gases (IIC group) are present, and the sensor needs to be mounted at a moderate distance from the junction box.

• Chemical and Petrochemical Plants – Surveillance of reactors, mixers, centrifuges, and fans in Zone 0, 1, and 2 classified areas where explosive vapours may occur, with the 6‑metre cable allowing flexible routing from the sensor to a safe junction box.

• Pharmaceutical and Food Processing – Vibration monitoring in solvent‑handling areas and dust‑explosive environments (e.g., sugar, flour, starch) where intrinsic safety is mandatory.

• Power Generation – Vibration measurement on gas turbines, generators, and auxiliary equipment in co‑generation and thermal power plants with potential explosive atmospheres.

• Marine and Offshore – Propulsion systems, deck machinery, and cargo pumps on tankers and FPSO vessels operating in hazardous zone classifications, where the 6‑metre cable provides sufficient reach for typical machinery layouts.

• Wastewater and Biogas – Monitoring of pumps, blowers, and mixers in biogas plants and wastewater treatment facilities where methane or hydrogen sulphide may be present.

• Hazardous Area Test and Measurement – Permanent installations for performance validation and predictive maintenance in Ex‑classified zones, where the integral cable simplifies installation and reduces potential leak paths.

Detailed Description of the Ex Version (444‑311‑000‑123)

The CE311 444‑311‑000‑123 is the Ex‑certified variant of the updated CE311 family, featuring a sensitivity of 50 μA/g, a temperature range of –40 °C to 125 °C, and a 6‑metre integral cable. It is designed for permanent installation in hazardous areas where intrinsic safety (Ex ia), non‑sparking (Ex nA), or dust ignition protection (Ex ID) is required, and where a moderate cable reach is beneficial for installation flexibility. The sensor is built around a symmetrical shear‑mode piezoelectric measuring element using polycrystalline material. The integrated electronics package, housed within the sensor casing, converts the charge generated by the piezoelectric element into a proportional current signal. The current‑modulated output (2‑wire system) carries both power to the sensor and the signal from the sensor over the same two conductors. Because the output is a current signal, it is largely insensitive to cable capacitance and electromagnetic interference, permitting cable runs of several hundred metres without signal attenuation or degradation. The 6‑metre cable adds approximately 0.63 nF pole‑to‑pole and 1.2 nF pole‑to‑casing, which is well within the capabilities of the current loop and does not affect the sensor’s performance. The lower cable capacitance of the updated series further enhances compatibility with intrinsic safety barriers, as the total loop capacitance remains well within the limits specified in the Ex certificates.

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 (KEMA 04 ATEX 1055 and IECEx DEK 15.0029). The sensor itself is designed with internal protection to ensure that under fault conditions, the energy remains below ignition thresholds. The intrinsic safety parameters (e.g., maximum voltage Ui, current Ii, power Pi, capacitance Ci, inductance Li) are provided in the certificate and must be respected when designing the loop. The 6‑metre cable capacitance is modest and typically well within the limits, making this length a safe and practical choice. The updated cable capacitance values (105 pF/m and 200 pF/m) are significantly lower than the legacy 200 pF/m and 400 pF/m, providing additional safety margin.

The ground‑isolated design ensures that the sensor case and mounting base are electrically isolated from the signal ground, preventing ground loops. The internal shielding and isolated electronics further attenuate electromagnetic interference, ensuring clean signal transmission even in environments with strong electrical fields.

The mechanical construction features a hermetically welded stainless‑steel housing (1.4441) that provides robust protection. The integral cable is welded to the sensor at the factory, creating a continuous, leak‑tight seal that prevents moisture ingress and ensures long‑term reliability. The cable is a twisted‑pair shielded cable, and the flexible stainless‑steel hose (1.4541) offers robust protection against abrasion, cutting, and chemical attack. The cable is terminated with flying leads (colour‑coded) allowing direct wiring to terminal blocks or junction boxes, eliminating the need for an intermediate connector that could be a potential failure point and a source of leakage in Ex zones. The 6‑metre length is a practical choice for many installations where the sensor is mounted on a medium‑sized machine and the junction box is located at a moderate distance.

The mounting interface consists of four M6×35 Allen bolts (12.9 steel) with four M6 spring‑steel washers. The recommended mounting torque is 15 N·m (11.1 lb‑ft), ensuring proper coupling and optimal high‑frequency response.

The CE311 444‑311‑000‑123 is factory‑calibrated at 120 Hz and 5 g peak at 23 °C, with the sensitivity verified to be within ±5 % of the nominal 50 μA/g. No subsequent calibration is required under normal use, but periodic verification (e.g., every 2‑5 years) is recommended for critical safety‑related applications.

This Ex version is certified for gas group IIC, temperature classes T6 to T3, covering a wide spectrum of ignition temperatures. Additionally, it carries Ex nA certification for Zone 2 and Ex ID for dust ignition protection by enclosure (for South Korea), making it suitable for a broad range of hazardous applications, including dust environments. The sensor is suitable for Zone 0 (continuous explosive gas atmosphere) and provides intrinsic safety for the most hazardous areas.

The 6‑metre cable length offers a significant advantage over the 3‑metre version for installations where the sensor must be mounted further from the junction box, such as on larger machines, or where the cable routing requires additional length to avoid sharp bends or to pass through cable trays. The stainless‑steel hose ensures that the cable remains protected even if exposed to mechanical stress or high temperatures.

Installation and Mounting Guidelines

Proper installation is essential to achieve the specified performance and maintain the Ex certification of the CE311 444‑311‑000‑123. 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 and the machine surface. A surface finish of 1.6 µm (63 µin) or better is recommended for optimal high‑frequency response.

• Bolts and Washers – Use the supplied M6×35 Allen bolts (12.9 steel) and M6 spring‑steel washers (DIN 7980). Apply the recommended torque of 15 N·m (11.1 lb‑ft) evenly across all four bolts. 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 Termination – Ex Requirements – The integral cable is protected by a flexible stainless‑steel hose. Route the cable with a minimum bend radius to avoid stress and internal damage (recommended > 50 mm). For a 6‑metre cable, ensure that the cable is not subjected to excessive tension or sharp bends. Secure the cable at intervals using P‑clips or cable ties, but avoid over‑tightening that could deform the hose. All cable glands and junction boxes in the hazardous area must be Ex‑certified and installed according to local regulations. The flying leads are colour‑coded; connect them to the monitoring system’s constant current supply and signal input, preferably through a certified junction box. The cable shield should be grounded at one end (typically at the monitoring system) to minimise electromagnetic interference.

• 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 (KEMA 04 ATEX 1055 / IECEx DEK 15.0029). The barrier must be located in the safe area or be certified for installation in the hazardous area. The supply voltage must be within 15 to 28 VDC, and the current must be between 5.5 and 7.5 mA. The signal is measured as the AC current component on the bias level. Ensure the monitoring system provides the appropriate signal conditioning (e.g., current‑to‑voltage conversion and high‑pass filtering). The total cable capacitance and inductance must be within the permissible limits to avoid spark ignition. Refer to the certificate for specific parameters (Ui, Ii, Pi, Ci, Li) and special conditions for safe use.

• 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 – The sensor is rated for continuous operation up to 125 °C. The temperature class T6…T3 is dependent on the ambient temperature and the surface temperature; ensure that the maximum surface temperature does not exceed the permissible limit for the specific T‑code. If the mounting surface exceeds 125 °C, use a thermal insulating adaptor (e.g., MA133) or mount the sensor remotely. Ensure that the cable hose is not routed over hot surfaces that exceed its material limits.

• Protection from Physical Damage – In harsh environments, protect the sensor and cable from impacts, abrasion, and chemical attack. The stainless‑steel hose provides substantial protection, but additional conduits or protective covers may be required in extreme conditions.

• 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 bias current. Record the bias current and signal levels for future reference.

Commissioning and Verification

After installation, the CE311 444‑311‑000‑123 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 current should be measured to confirm it is within the specified 5.5 to 7.5 mA range. 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 current change (50 μA/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.

Ordering Information

The CE311 444‑311‑000‑123 is ordered using the following designation:

Note: This updated series (ending in 013, 023, 033, 043, 113, 123) supersedes the legacy series (012, 022, 032, 042, 112, 122). The new series features improved cable capacitance specifications and updated documentation. Ex versions feature intrinsic safety (Ex ia), non‑sparking (Ex nA), or dust ignition protection (Ex ID) certification.

Accessories

A range of accessories is available to complement the CE311 444‑311‑000‑123, including mounting adaptors, connectors, junction boxes, and galvanic separation units.

Note: For Ex installations, use only certified connectors, cables, and barriers as specified in the relevant Ex certificates.

Disposal and Environmental Compliance

At the end of its service life, the CE311 444‑311‑000‑123 must be disposed of in accordance with local environmental regulations. The sensor contains stainless steel, electronic components, and piezoelectric materials; the cable contains metal conductors and insulation. 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.