The KX series is an intrinsically safe industrial pressure sensor engineered for precision measurement within hazardous environments containing explosive gases or combustible dust. These sensors are built using proven thick film on stainless steel technology, featuring a robust, totally welded metal structure without internal seals to ensure compatibility with a wide variety of process fluids. Beyond its hazardous area certifications, the series is standardly supplied with SIL2 functional safety approval according to IEC/EN 62061, making it a reliable component for safety-related control systems in high-demand industrial applications.
Product Parameters
- Pressure Range: Available in various configurations from -1 up to 1000 bar.
- Output Signal: Standard 4-20 mA analog current using a 2-wire system.
- Measurement Accuracy: Typical accuracy of ±0.15% FS with a maximum limit of ±0.2% FS.
- Power Supply: Requires a regulated 10 to 30 Vdc source via a certified isolation barrier.
- Ingress Protection: Environmental sealing ranges from IP65 to IP67 depending on the chosen electrical connector.
- Hazardous Area Approval: ATEX certified for Group II (Gas) Category 1G and Group III (Dust) Category 1D.
- Temperature Class: Certified for T4, T5, and T6 classes with corresponding ambient limits.
- Safety Integrity Level: SIL2 approved for use in safety-related electrical and electronic control systems.
- Construction Materials: Housing and pressure port manufactured from AISI 304 and 17-4PH stainless steel.
Product Description
The KX series is specifically designed to meet the rigorous safety and performance requirements of modern industrial processes located in explosive atmospheres. By utilizing a thick film sensing element on a stainless steel substrate, the sensor provides high stability and long-term reliability even when exposed to aggressive media. The absence of internal sealing gaskets further enhances its robustness, preventing potential leak paths and ensuring a long service life in demanding environments.
For applications involving high-pressure hydraulics, the series addresses common safety risks such as cavitation and liquid hammer. Upon request, the sensors can be fitted with an integrated pressure snubber featuring a 0.5 mm diameter hole, which effectively dampens harmful pressure peaks to protect the internal sensing element from damage. This feature, combined with a fast response time of less than 1 millisecond, ensures both protection and real-time monitoring accuracy.
The integration of SIL2 certification as a standard feature simplifies the design process for machine builders and systems engineers. The device is certified for “High Demand Mode” applications, allowing it to serve as the primary pressure variable feedback in safety-related parts of a control system (SRP/CS). In the event of specific internal failures, the sensor is programmed to provide output saturation—either high or low—allowing the control system to detect the fault and enter a safe state.
The KX is also available as a non sparking Ex nA / Ex ec approved version.
Product Features
The KX series is engineered for high-performance and safety in challenging industrial environments, integrating advanced explosion protection with robust mechanical design. Featuring comprehensive ATEX/PESO certifications and SIL2 functional safety, the series ensures reliable operation in hazardous areas, while its durable stainless steel construction and specialized protection features safeguard against electrical faults, mechanical stress, and hydraulic surges.
Hazardous Area Certifications (ATEX/PESO)
The KX series carries comprehensive ATEX and PESO certifications, designating it as an intrinsically safe instrument for use in the most volatile industrial environments. For users operating in oil refineries, chemical processing plants, or pharmaceutical facilities, these certifications provide the legal and technical assurance that the device will not act as an ignition source in the presence of explosive gases (Category 1G) or combustible dust (Category 1D). This level of protection allows for direct installation in Zone 0 and Zone 20 areas, minimizing the need for complex explosion-proof housing and simplifying the overall safety infrastructure of the plant.
SIL2 Functional Safety
Functional safety is a critical requirement for modern industrial automation, and the KX series meets this demand by providing SIL2 (Safety Integrity Level 2) approval as a standard configuration. This certification, according to IEC/EN 62061, signifies that the transmitter has undergone rigorous assessment of its hardware and software reliability. For industrial users, this means the device can be seamlessly integrated into Safety Instrumented Systems (SIS) to protect personnel, the environment, and high-value assets. The inclusion of SIL2 as standard eliminates the extra cost and lead time typically associated with sourcing safety-rated instrumentation, ensuring that every unit is ready for high-demand safety applications.
Welded Stainless Steel Structure
Engineering integrity is at the core of the KX series, which features a totally welded stainless steel construction that eliminates internal O-rings or O-ring-related seal failures. By using AISI 304 and 17-4PH stainless steel, the transmitter offers exceptional compatibility with a vast range of aggressive process fluids and hydraulic oils. For the operator, this design choice translates to a leak-proof measurement solution that maintains its seal integrity even under extreme pressure cycling. The absence of internal seals reduces maintenance requirements and prevents potential contamination of the process media, making it ideal for high-purity or highly corrosive industrial environments.
Mechanical Stress Resistance
Industrial environments are often characterized by heavy machinery that generates significant mechanical stress. The KX series is built to withstand these conditions, boasting a shock rating of up to 100g and vibration resistance up to 20g. This extreme durability ensures that the transmitter continues to provide accurate data even when mounted on high-impact hydraulic presses or vibrating pump stations. By resisting mechanical fatigue and physical damage, the transmitter reduces the risk of unplanned downtime and frequent replacements, providing industrial users with a reliable sensing solution that thrives in the toughest mechanical conditions.
Integrated Pressure Snubber
Hydraulic systems often suffer from rapid pressure spikes, cavitation, and fluid hammer effects that can instantly destroy sensitive measurement diaphragms. To combat this, the KX series offers an optional integrated pressure snubber with a 0.5 mm orifice. This feature dampens high-frequency pressure peaks before they reach the sensing element, effectively acting as a mechanical filter. For the user, this means significantly enhanced longevity for the instrument in high-pressure hydraulic applications. Despite this protection, the device maintains a fast response time, ensuring that the control system receives timely data without the risk of sensor fatigue or catastrophic failure.
Electrical Protection
Reliable electrical performance is guaranteed through a comprehensive suite of protective features, including short-circuit, overvoltage, and reverse polarity safeguarding. In the complex wiring environments of industrial control cabinets, these protections prevent the transmitter from being damaged by common installation errors or electrical faults in the loop. Furthermore, the 4-20 mA output is designed with saturation levels that signal internal failures to the PLC, allowing the system to enter a safe state immediately. This electrical robustness ensures the longevity of the device and the safety of the entire control loop infrastructure.
Product Applications
The KX series’ combination of intrinsic safety and SIL2 functional safety makes it an essential choice for a wide range of hazardous industrial applications where precision, reliability, and safety are paramount.
Oil and Gas Extraction and Processing
In oil and gas facilities, the KX series acts as a critical sensing component where the atmosphere is frequently saturated with explosive gases. Its intrinsic safety (ATEX) design prevents the transmitter from becoming an ignition source, making it essential for monitoring pressure in extraction wells and processing pipelines. Furthermore, the SIL2 functional safety approval allows engineers to integrate the transmitter directly into safety-instrumented systems (SIS) that manage emergency shutdowns, ensuring that process pressure anomalies are detected and mitigated before they lead to hazardous releases.
Chemical and Petrochemical Plants
Chemical plants often deal with volatile vapors and mists that necessitate the highest levels of electrical protection. The KX series utilizes its intrinsically safe certification to operate continuously within these hazardous zones, providing precise pressure data without the risk of sparking. By incorporating SIL2-certified feedback into the control loop, plant operators can maintain rigorous safety standards, relying on the transmitter to provide fail-safe signals that alert the control system to enter a safe state in the event of hardware failure.
Industrial Hydraulic Systems
Industrial hydraulic systems frequently operate under high-pressure conditions where mechanical failure could pose significant risks. The KX series provides the reliable pressure feedback needed for safety-critical machine control, with its SIL2 certification ensuring that the monitoring system itself meets functional safety requirements. When these systems are located in areas with explosive potential, the transmitter’s intrinsic safety ensures that the equipment remains compliant and protected against electrical ignition, providing both operational stability and regulatory peace of mind.
Pharmaceutical and Food Production
In environments such as pharmaceutical manufacturing or food processing, the presence of combustible dust creates a significant explosion hazard (Zone 20). The KX series is purpose-built for such conditions, leveraging its intrinsic safety to operate safely amidst airborne particles without risking ignition. The SIL2 approval further enhances the value of these sensors in these industries by facilitating the design of safety-related control parts (SRP/CS), ensuring that pressure monitoring is accurate and reliable for maintaining process integrity and worker safety.
Safety-Critical Machinery Control
For machinery requiring automated safety protocols, the KX series is an ideal pressure variable source due to its standard SIL2 functional safety rating. This certification allows the transmitter to serve as the primary feedback mechanism in safety-related electrical and electronic control systems. By ensuring that any internal fault leads to a predictable, safe output state, the transmitter assists manufacturers in achieving high-demand mode compliance for their equipment, effectively protecting operators and infrastructure from pressure-related accidents.
Paint and Solvent Manufacturing
Paint and solvent facilities, which are often classified as Zone 0 or Zone 20 environments, demand instrumentation that can withstand constant exposure to flammable substances. The KX series utilizes its intrinsically safe design to function within these restricted areas, providing continuous monitoring where other sensors might introduce unacceptable risks. The combination of this high-level explosion protection with the reliability of SIL2 certification provides a dual-layer of safety, ensuring that even in the most volatile manufacturing environments, pressure remains tightly controlled and monitored.
Propane gas supply line
Use this sensor to measure the pressure of a propane gas supply line.
- SKU ID: s1-kx-91-29256
- Part No: KX-E-3-F-B04U-T-V-4-2130X000X30
- Pressure Range: 0 to 4
- Units: bar
- Range Type: Positive Gauge (atm to +P)
- Output Signal: 4-20mA ATEX Intrinsic Safety, SIL2
- Electrical Connection: Integral shielded cable (3 metre long)
- Process Connection: G1/2 male (DIN 3852-E)
- Temperature Class: T4 (-40…+80 degC)
Product Specifying Guide
Select the measurement range
Identify the required pressure range for your application, choosing from standard options between -1…+1 bar and 0…1000 bar. Ensure the expected system pressure falls within the operating range, keeping in mind the specified overpressure and burst pressure limits for each range.
Choose the mechanical connection
Select the appropriate pressure port for your piping or manifold. Standard options include G 1/4 gas male, G 1/2 gas male, 1/4”-18 NPT male, and 1/2”-14 NPT male. For hydraulic applications, determine if the optional internal pressure snubber is required to protect against peaks.
Pick the electrical connector
Choose an electrical interface that matches your cabling and environmental requirements. Available connectors include EN 175301-803 Type A or C, M12x1, 7-pole screw connectors, 6-pole bayonets, or integral shielded cables. Each choice will determine the final ingress protection (IP) rating of the assembly.
Determine the required temperature class
Specify the temperature class (T4, T5, or T6) based on the maximum ambient and process temperatures at the installation site. This selection is critical for maintaining ATEX compliance and ensures the sensor operates reliably within its certified thermal limits.
Confirm regional certifications
Verify if you require the standard ATEX approval or additional regional certifications such as PESO for specific international markets. This ensures the product is legally and technically compliant with the safety regulations of the destination country.
Part Number Builder
Generate or decode KX ordering code
Installation & Operation Guide
Verify safety barrier compatibility
Before installation, confirm that the associated galvanic isolation barrier in the safe area meets the [Ex ia] IIC requirements. The barrier’s maximum output parameters (Uo, Io, Po) must be less than or equal to the sensor’s internal safety limits (Ui, Ii, Pi), while its allowed inductance (Lo) and capacitance (Co) must exceed the sum of the sensor and cable values.
Mechanical mounting procedure
Install the sensor into the process port using a suitable sealing gasket, such as Viton for DIN 3852-E connections. Use a wrench on the hexagonal part of the sensor body (Ch 22 or Ch 27) and tighten to a recommended torque of 30 Nm, ensuring not to exceed the 40 Nm maximum limit.
Electrical wiring and shielding
Connect the 4-20 mA current loop according to the specific pinout for your chosen connector. Use only shielded cables, grounding the shield at the PLC or controller side in the safe area while leaving it floating at the sensor side to prevent ground loops and interference.
Grounding and interference prevention
Ensure the transducer is properly grounded, typically through the machine body or equipment it is mounted on. To maintain signal integrity, route the sensor’s signal cables separately from high-power electrical cables.
Initial inspection and testing
Perform a visual inspection to confirm all mechanical and electrical connections are secure. Once powered through the safety barrier, verify that the zero-pressure output is approximately 4 mA and that the sensor responds correctly to known pressure changes within the process.
Product Help
Safe connection requirements
How do I safely connect the KX series sensor to a power source in a hazardous area?
The sensor must be connected to an [Ex ia] IIC certified galvanic isolation barrier. This barrier must limit the electrical parameters to a maximum voltage (Uo) of 30 V, a maximum current (Io) of 100 mA, and a maximum power (Po) of 0.75 W to maintain the intrinsic safety of the loop.
Meaning of SIL2 certification
What does the SIL2 approval signify for my industrial equipment?
SIL2 (Safety Integrity Level 2) certification means the device has been independently verified for functional safety in accordance with IEC/EN 62061. It confirms that the sensor can be used in safety-related control systems where the pressure of a fluid is a critical variable that must be monitored to prevent hazardous situations.
Suitability for dust environments
Can this pressure sensor be used in areas where combustible dust is a concern?
Yes, the KX series is ATEX certified for Group III, Category 1D (Zone 20) environments. Depending on the ambient temperature, it is rated for maximum surface temperatures of 90°C, 100°C, or 110°C, even when covered by a dust layer up to 200 mm thick.
Calibration and maintenance intervals
How often does the sensor require maintenance or recalibration?
A visual inspection of electrical and mechanical connections should be performed every two years. The pressure channel should be checked for obstructions annually, and a full calibration test to verify the transduction curve is recommended every four years.
Protection against hydraulic spikes
What should I do if my system experiences frequent pressure peaks from pumps or valves?
You should request the version of the KX series equipped with an integrated pressure snubber. This snubber uses a 0.5 mm diameter hole to dampen harmful spikes, protecting the sensor without significantly affecting the overall response time.
Vacuum tolerance
Can this sensor withstand a vacuum of -1bar?
Yes you can apply full vacuum to this sensor, it is a fully welded sensing element, so it will be completely leak tight and there is no oil filling behind the diaphragm which eliminates any vapour pressures forming which could cause a zero shift.
100degC minimum temperature range
Is there something we could do to increase the temperature range? We need a minimum of 100degC?
The maximum temperature will depend on whether it is process or ambient surrounding temperature. The maximum process temperature is 125degC (sensor module), and the maximum ambient temperature is 105degC (electronics) for installing in a non-hazardous area (safe area).
If you are installing in a hazardous area then the specification is limited by the maximum allowed surface temperature of the sensor which is defined by the ATEX intrinsically safe temperature class for which you can choose T4 – Tamb max = +80degC, T5 – Tamb max = +70degC, or T6 – Tamb max = +60degC depending on the gas group present.
Maximum ambient operating temperature in hazardous area
What is the maximum environmental temperature this sensor will operate in as part of an intrinsically safe installation?
The sensor electronics is designed to withstand an environmental temperature of 105ºC (221ºF), however when used in an hazardous area, the ATEX and IECEx certification defines the limits of surface temperature of the device into a range of classes from T1 to T6. In order to ensure the surface temperature is not exceeded, the ambient temperature must not exceed a specific value. Since electrical and electronic devices all produce different levels of heat internally, the allowed ambient temperature (Tamb) will be different for one device to another. For the KX the highest temperature class is T4 where the max ambient temperature surrounding the sensor should not exceed 90ºC (176ºF)
Current output for -1 to +1 bar range
What is the output at 4mA and 20mA for the -1 bar to 1 bar range?
The output signal will be -1 bar = 4 mA and +1 bar = 20 mA.
Ink pressure measurement
Can this sensor be used for measuring a liquid like Ink?
Ink is quite a broad category of chemicals, so we can only advise the materials in contact with the media so the user can assess whether it will be compatible with a particular Ink type.
The KX has full welded 17-4PH and AISI 430F Stainless Steel without any internal seals, however there is a captive Viton seal around the thread to seal the process connection, but this can easily be replaced by the customer with a different type of material if necessary.
Zone 1 use
Is this pressure sensor suitable for use in a zone 1 area with a barrier?
The ATEX certification marking is II 1G Ex ia IIC T4, therefore it is suitable for ATEX zone 0 and below, and must be used with a suitable intrinsically safe barrier and installed to ATEX approved standards by certified electricians or electrical contractors.
Related Documents
Specification data sheet
Request Product Price
Please select the options you require for the KX ATEX Intrinsically Safe SIL2 Approved Pressure Sensor in your application and request a quote.