The KX series is an industrial pressure transmitter specifically certified for use in Zone 2 hazardous areas, employing non-sparking (Ex nA) and increased safety (Ex ec) protection modes. Built with thick film on stainless steel technology, these sensors feature a totally welded structure devoid of internal seals, ensuring robust compatibility with a wide range of fluids and gases. This version maintains the standard high-performance specifications of the series, including SIL2 functional safety approval according to IEC/EN 62061, making it an ideal choice for machinery manufacturers requiring precision measurement and functional reliability in atmospheres with flammable gases or dust.
Product Parameters
- Pressure Range: Available in measurement ranges from -1 to +1 bar up to 0 to 1000 bar.
- Output Signal: Standard amplified current output of 4-20 mA using a 2-wire system.
- Typical Accuracy: Measurement precision of ±0.15% Full Scale (FS) typical, with a maximum of ±0.2% FS.
- Supply Voltage: Operates on a standard power supply range of 10 to 30 Vdc.
- Temperature Class: Certified for T6, T5, & T4 temperature classification, supporting ambient and process temperatures up to +80°C.
- Protection Rating: Ingress protection levels ranging from IP65 to IP67 depending on the selected electrical connector.
- Functional Safety: Certified SIL CL 2 by TÜV Rheinland for use in high-demand mode safety applications.
- Housing Material: External casing and wetted parts constructed from AISI 304 and 17-4PH stainless steel.
- Response Time: Fast dynamic response of less than 1 millisecond for 10% to 90% FS changes.
Product Description
The KX series Non-Sparking variant provides a streamlined safety solution for Zone 2 hazardous areas, where explosive atmospheres are less likely to occur or exist only for short periods. Unlike intrinsically safe models that require external galvanic barriers, the Ex nA/ec protection mode focuses on the device’s ability to prevent sparks and excessive surface temperatures during normal operation. This design choice often simplifies electrical installation while maintaining high safety standards for chemical, pharmaceutical, and oil and gas facilities.
At the core of the transmitter is a sensing element deposited directly onto a stainless steel diaphragm using high-temperature screen printing. This thick film technology results in an extremely sturdy and reliable sensor capable of withstanding significant overpressure and burst pressures without degrading performance. The monolithic structure eliminates the need for internal O-rings or silicone oil filling, which prevents potential fluid contamination and mechanical failure due to seal degradation over time.
Functional safety is integrated into the series as a standard feature, rather than an optional add-on. The SIL2 certification ensures that the transmitter can be used as a primary sensing element in safety-related parts of a control system (SRP/CS), compliant with the European Machinery Directive. In the event of internal component failure, such as a broken bridge or supply issue, the transmitter enters a controlled alarm state by saturating the output signal below 3.6mA or above 24mA, allowing the controller to immediately identify a fault and trigger safety protocols.
The KX is also available as an intrinsically safe version.
Product Features
The KX series integrates SIL2 functional safety and ATEX Zone 2 certification within a rugged, hermetically welded stainless steel design, providing a high-reliability pressure sensing solution for demanding industrial environments.
ATEX Zone 2 Certified Protection
The KX series is specifically engineered for deployment in Zone 2 hazardous areas, utilizing dual protection modes: Non-Sparking (Ex nA) and Increased Safety (Ex ec). This certification ensures that the equipment is designed to prevent the occurrence of arcs, sparks, or hot surfaces during normal operation that could otherwise ignite an explosive atmosphere. By adhering to these standards, the transmitter provides a reliable and cost-effective safety solution for environments where flammable gases, vapors, or mists are infrequently present or only exist for short durations.
Standard SIL2 Functional Safety
Every unit in the KX series comes standard with SIL2 (Safety Integrity Level 2) functional safety approval according to IEC/EN 62061. This certification facilitates seamless integration into safety-related control systems, serving as a critical component in risk reduction strategies for industrial machinery. The integrated safety firmware continuously monitors the sensor’s health, ensuring that the output signal accurately reflects the process pressure or enters a defined safe failure state if an internal fault is detected.
Advanced Thick Film Technology
Utilizing state-of-the-art thick film on stainless steel technology, the sensing element is deposited directly onto the diaphragm through a high-temperature firing process. This method creates a molecular bond between the sensor and the substrate, resulting in exceptional long-term stability and resistance to thermal drift. The absence of intermediate bonding materials ensures that the transmitter maintains high precision and repeatabilty even when subjected to extreme environmental conditions and rapid temperature fluctuations.
Hermetically Welded Structure
The mechanical integrity of the transmitter is underpinned by a totally welded metal construction that completely eliminates the need for internal O-rings, gaskets, or elastomeric seals. This monolithic design prevents potential leak paths and ensures compatibility with aggressive fluids and gases that might otherwise degrade traditional sealing materials. The result is a maintenance-free pressure interface that offers superior reliability in high-pressure and vacuum applications alike.
Versatile Pressure Range Capability
The KX series offers an expansive measurement envelope, capable of handling pressures starting from compound vacuum levels (-1 bar) up to ultra-high pressures of 1000 bar gauge. This versatility allows engineers to standardize on a single sensor platform across a diverse range of plant equipment, from low-pressure pneumatic lines to high-force hydraulic actuators. Each range is optimized to provide the highest possible signal resolution while maintaining a significant overpressure margin.
Integrated Pressure Snubber
To safeguard the sensing diaphragm against the destructive effects of cavitation, liquid hammer, and rapid pressure pulsations, an optional integrated snubber can be specified. This feature consists of a precision-drilled 0.5mm orifice within the pressure port that acts as a mechanical low-pass filter. By damping high-frequency transients before they reach the active sensing area, the snubber significantly extends the operational life of the transmitter in dynamic hydraulic systems.
High Vibration and Shock Resistance
Designed for the rigors of heavy industrial use, the transmitter features a robust mechanical architecture that is highly resistant to mechanical stress. It is rated to withstand continuous vibrations up to 20g (sinusoidal) and mechanical shocks up to 100g. This makes the KX series particularly suitable for installation on large-scale reciprocating compressors, mobile hydraulic platforms, and other machinery where severe physical disturbances are a routine part of the operating environment.
Premium Stainless Steel Construction
All wetted parts and external housing components are manufactured from high-grade stainless steel alloys, specifically 17-4PH for the sensing diaphragm and AISI 304 for the main body. These materials are selected for their excellent mechanical strength and broad chemical resistance, ensuring the transmitter can operate reliably in contact with a wide variety of industrial media. The high-quality finish also provides an additional layer of protection against atmospheric corrosion in coastal or offshore environments.
Product Applications
The KX series is engineered to provide reliable and compliant pressure monitoring in a variety of hazardous industrial environments. By leveraging non-sparking (Ex nA) and increased safety (Ex ec) protection, these transmitters ensure safe, efficient, and cost-effective operation in Zone 2 areas without the complexity of traditional intrinsic safety requirements. The following applications illustrate how the series supports high-performance measurement across key industrial sectors.
Oil and Gas Refineries and Distribution Centers
In oil and gas environments, the KX series leverages Ex nA and Ex ec protection to provide robust, reliable pressure monitoring in Zone 2 areas without the complex overhead of intrinsic safety barriers. By ensuring that the device cannot generate arcs, sparks, or hot surfaces during normal operation, these protection modes allow for simplified electrical installation across large-scale distribution networks. This makes the transmitter an ideal choice for monitoring pressures in fuel pipelines and storage monitoring where flammable gas mixtures may intermittently exist, significantly reducing total system installation and maintenance costs while maintaining high safety standards.
Chemical Processing Plants
Chemical processing facilities often present complex challenges involving flammable solvents and corrosive media that demand both durability and high-level safety compliance. The KX series utilizes Ex nA/ec protection to ensure that even in the presence of potentially ignitable vapors, the sensing electronics remain inert and safe. Because these protection modes do not require external galvanic isolation, they are particularly advantageous for large, sprawling plants where signal integrity must be maintained over long cable runs, providing a highly cost-effective yet compliant way to monitor process pressure in critical chemical reaction vessels and supply lines.
Hydraulic and Pneumatic Industrial Machinery
For safety-critical industrial machinery, the integration of Ex nA and Ex ec protection modes ensures that the pressure transmitter does not become an ignition source in the event of a hydraulic fluid leak or pneumatic seal failure. This added safety layer is crucial for modern machinery operating in hazardous zones, as it prevents potential ignition without requiring specialized, low-energy wiring configurations. The combination of high-vibration resistance and non-sparking protection allows these transmitters to be mounted directly on actuators and control valves, where they can continuously monitor system pressure without compromising the safety integrity of the wider machine design.
Power Generation Facilities
Power generation plants utilizing gas-fired turbines or combustible fuels require instrumentation that can withstand high-pressure environments while ensuring strict hazardous area compliance. The KX series, with its Ex nA/ec design, provides a secure way to monitor fuel injection pressure, coolant lines, and lubrication systems in Zone 2 areas. These protection modes ensure that the device remains safe and operational even in environments characterized by rapid cycling and temperature fluctuations, offering a reliable, maintenance-free solution that integrates easily into existing control systems without the need for additional safety-barrier enclosures.
Pharmaceutical Manufacturing Zones
Pharmaceutical production often involves the use of volatile solvents and chemicals, categorizing various processing zones as potentially hazardous. The KX series is highly suitable for these environments, as the Ex nA/ec protection modes allow for safe operation in Zone 2 without the rigorous installation requirements of Ex ia (intrinsically safe) circuits. This allows manufacturers to utilize standard, high-performance sensing equipment while ensuring that the electronics cannot ignite hazardous vapors, facilitating compliance with safety regulations while maintaining the precise pressure monitoring required for delicate, high-purity batch processes.
Large-Scale Compressors and Pump Stations
Large-scale reciprocating compressors and pump stations are frequently subject to intense mechanical stress, vibration, and the presence of combustible media, making equipment reliability and safety essential. The KX series provides a robust, monolithic stainless steel solution that resists vibration-induced wear, while the Ex nA/ec protection modes ensure that the electronics do not create sparks, even when subjected to the mechanical strain of a high-pressure pumping application. This ensures consistent, safe pressure data acquisition in hazardous pump houses, allowing operators to detect pressure surges and failures immediately without concern for the transmitter’s ignition risk.
Product Specifying Guide
Determine the pressure range
Select the nominal pressure range required for your process. The series covers ranges from compound vacuum (-1 to +1 bar) up to extreme high pressures (1000 bar). Ensure that the expected operating pressure is within the compensated temperature range of -20 to +85°C for maximum accuracy.
Select the mechanical interface
Choose the pressure port thread that matches your existing manifold or pipework. Standard options include G 1/4 or G 1/2 gas male threads (DIN 3852-E) and 1/4” or 1/2” NPT male threads. For hydraulic applications with risk of cavitation, verify if the internal snubber option is necessary.
Choose electrical connection type
Match the electrical connector to your system’s cabling requirements. Options range from standard DIN 43650 Form A or Form C plugs to M12x1 circular connectors, multi-pole bayonets, or integral cables for permanent installations.
Verify certification requirements
Confirm that the ATEX Ex nA/ec certification for Zone 2 is appropriate for your installation site. If your application requires higher safety levels for Zone 0 or Zone 1, you may need to specify the intrinsically safe (Ex ia) variant instead.
Part Number Builder
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Installation & Operation Guide
Mechanical installation steps
Thread the sensor into the process port by hand to ensure no cross-threading occurs. Use a wrench on the hexagonal body (do not turn by the housing) and tighten to 30 Nm for standard ports. For DIN 3852-E connections, ensure the Viton sealing gasket is correctly seated.
Electrical wiring and loop setup
Wire the sensor in series with the 10-30 Vdc power supply and the receiving instrument. Always use shielded cables to prevent electromagnetic interference, grounding the shield only at the controller or safe-area side while leaving it floating at the sensor end.
Grounding the device
The transducer must be properly grounded to prevent electrical noise and ensure safety. This is normally achieved through the metal contact of the pressure port with the machine body or equipment it is installed on.
Troubleshooting the output
If the sensor provides an output below 3.6 mA, check for broken power supply cables, a disconnected sensor, or a failure in the bridge electronics. If the sensor outputs a saturated “HIGH” signal (above 24 mA), it may indicate a broken bridge or electronic overheating.
Periodic safety verification
To maintain the functional safety rating, conduct a sensor calibration test every four years. This involves applying known pressure points to the transducer and checking that the output signal accurately follows the transduction curve within the specified tolerance.
Product Help
Understanding Zone 2 protection
What is the advantage of using the Ex nA/ec version over an intrinsically safe model?
The Ex nA (Non-Sparking) and Ex ec (Increased Safety) protection modes are designed specifically for Zone 2 hazardous areas. The primary advantage is often a simplified installation process, as these devices generally do not require the use of external zener barriers or galvanic isolators required for intrinsically safe (Ex ia) circuits.
Managing pressure spikes
How does the sensor handle sudden pressure peaks in hydraulic circuits?
For applications with high-dynamic pressure pulsations, cavitation, or liquid hammer, the sensor can be supplied with an integrated pressure snubber. This snubber utilizes a 0.5mm diameter through-hole to dampen peaks and eliminate harmful phenomena that could otherwise damage the sensing diaphragm.
SIL2 reliability data
Can I use this transmitter in a high-demand safety loop?
Yes, the KX series is certified for “High Demand Mode” use by TÜV Rheinland in accordance with IEC/EN 62061. It has been tested to meet Safety Integrity Level 2 (SIL CL 2) requirements, making it suitable for use in safety-related programmable electronic control systems where pressure is the safety variable.
Maintenance of the pressure channel
What maintenance is required to keep the sensor working accurately in harsh environments?
Annual visual inspections should be conducted to check for any occlusion of the pressure channel. The inspection involves removing the probe from its process seat to ensure the channel is clear of any residue or material caps that could interfere with pressure transduction.
Ingress protection options
Which electrical connection offers the best environmental protection?
The environmental sealing depends on the connector chosen; for example, the M12x1 connector (Code Z) and the 7-pole M16 connector (Code P) provide an IP67 rating. The 6-pole bayonet (Code V) provides IP66, while the standard DIN connectors (Code E/M) are rated to IP65.
Related Documents
Specification data sheet
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