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
- ATEX and PESO certified for comprehensive protection in gas and dust hazardous areas.
- SIL2 functional safety approval provided as a standard configuration for all units.
- Totally welded stainless steel structure eliminates the need for internal O-rings or seals.
- High resistance to mechanical stress with shock ratings up to 100g and vibration up to 20g.
- Optional integrated pressure snubber to eliminate damage from hydraulic peaks and cavitation.
- Wide ambient and process temperature range compatibility from -40 to +125°C.
- Comprehensive electrical protection including short circuit and reverse polarity safeguarding.
- Traceable calibration against international standards for guaranteed measurement accuracy.
Product Applications
- Oil and gas extraction and processing facilities requiring intrinsically safe instrumentation.
- Chemical and petrochemical plants where explosive vapors or mists are present.
- Industrial hydraulic systems prone to rapid pressure fluctuations and peaks.
- Pharmaceutical and food production areas with combustible dust hazards.
- Safety-critical machinery control systems requiring SIL2 certified pressure feedback.
- Paint and solvent manufacturing environments categorized as Zone 0 or Zone 20.
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.
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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
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