What is the difference between a force transducer and a load cell?

Force transducers and load cells are based on the same measuring principle – the strain gauge – and convert mechanical forces into electrical signals. The term load cell is predominantly used in weighing and process engineering, while force transducers cover the broader spectrum of force and torque measurement technology: from test benches in the aerospace industry to materials testing. interfaceforce® eK distributes both types in measuring ranges from 0,5 Newtons to 30 Meganewtons.

What types of force transducers does interfaceforce® eK offer?

The portfolio includes low-profile force transducers, S-shaped force transducers, miniature force transducers, measuring bolts, force rings, bending beam load cells, cylindrical high-load sensors, and multi-component transducers for up to 6 degrees of freedom (6DoF). All standard models are strain gauge based and supplied with a calibration certificate. Custom designs are developed according to customer specifications.

Which torque transducers are suitable for rotating applications?

For rotating shafts, torque measuring shafts (e.g., T2, T4, T6, T8, T11, T22, T25) are available, which operate without contact and without slip rings. The measuring ranges extend up to 10 kN·m. For static or reactive applications – such as in test benches or for measuring bolt preload – reaction torque transducers are used. Both variants provide strain gauge-based signals and are compatible with the measuring amplifiers from interfaceforce® eK.

How does the XSENSOR pressure distribution system work and what is it used for?

XSENSOR systems measure surface pressure distribution using ultra-flexible sensor mats in various geometries and resolutions. These imaging systems deliver precise, reproducible results and are used in automotive and medical technology, biomechanics, and point-of-sale applications – for example, for seat pressure analysis, tire contact patch measurement, mattress diagnostics, and wiper testing. The XSENSOR laboratory is accredited according to ISO/IEC 17025 (A2LA).

What measurement accuracy do the force transducers from interfaceforce® eK achieve?

The low-profile force transducers of the Interface series (e.g., 1200, 1201, 3200) typically achieve a total static error band of ≤ 0,02% of the nominal value (full-scale output). The Gold Standard® and Platinum Standard® reference force transducers are suitable for calibration tasks according to ISO 376 Class 0,5. All sensors are supplied with a calibration certificate; A2LA-accredited certificates according to ISO/IEC 17025 are available upon request.

Does interfaceforce® eK also perform calibrations of third-party sensors?

Yes. The calibration laboratory of interfaceforce® eK is ISO/IEC 17025 accredited (A2LA and DAkkS mutually recognized within the framework of the ILAC MRA) and calibrates force measuring devices regardless of the manufacturer. Supported standards: ISO 376, DKD-R 3-3, ASTM E74, VDI/VDE 2624, and custom calibration procedures. Force measuring ranges: 0,5 N to 250 kN (tension and compression). An RMA number will be issued in advance for submissions; the delivery address for calibrations and repairs is c/o SETFLEX, Oppelner Str. 23, 41199 Mönchengladbach, Germany.

How does a calibration process work and how long does it take?

The process begins with an inquiry via contact form or email; interfaceforce® eK promptly issues an RMA number. Upon receipt of the device, calibration is performed in an ISO 17025-accredited laboratory using static tensile and/or compressive force measurements with traceable transfer standards (DAkkS, NIST, or PTB). Calibrations according to ISO 376 or DKD-R 3-3 include multiple load stages in various mounting positions. Turnaround times are short – precise details are available upon request. The completed calibration certificate is internationally recognized.

Which force transducers are suitable for use in ATEX or explosion-hazardous areas?

For hazardous areas (ATEX/IECEx), interfaceforce® eK offers force transducers from the 3400 series as well as hermetically sealed sensor variants made of stainless steel. These models are designed for harsh and potentially explosive environments and deliver reliable measurement results even under continuous operation. For specific hazardous area requirements (Zone 1, Zone 2, etc.), we recommend individual consultation, as suitability depends on the respective device category and the medium being used.

From what quantity are special solutions and customer-specific force transducers available?

Custom designs are available even for single units. interfaceforce® eK develops customer-specific force transducers, torque transducers, and multi-component sensors based on over 25 years of experience and in-house strain gauge manufacturing. Rapid engineering and rapid prototyping enable solutions to be implemented in short lead times – from concept to series production. Application areas range from niche markets with small production runs to OEM integrations in high-volume series.

What distinguishes interfaceforce® eK from other providers in force measurement technology?

interfaceforce® eK has been the exclusive distributor in Germany for Interface Inc. (founded in 1968, Scottsdale, USA) since 1999 – one of the world's leading manufacturers of precision strain gauge-based force transducers. The service portfolio combines American manufacturing quality with local support: an ISO 17025-accredited calibration laboratory in Germany (A2LA/DAkkS, ILAC MRA), manufacturer-independent calibrations and repairs, custom manufacturing starting from a single unit, and exclusive distribution of XSENSOR pressure distribution systems. Measuring ranges from 0,5 Newtons to 30 Meganewtons cover virtually every industrial force measurement application.

What output signal do the force transducers provide, and what measuring amplifier do I need?

Strain gauge-based force transducers deliver a bridge signal of typically 2 mV/V or 4 mV/V at rated load. Further processing requires a measuring amplifier that converts this signal into a usable format – e.g., 0–10 V, 4–20 mA, USB, IO-Link, or digital interfaces. interfaceforce® eK offers suitable measuring amplifiers as complete measurement chains: from simple digital displays (IFFDA93, IFFDA5) and 8-channel data acquisition systems (IFFBX8) to wireless telemetry systems (WTS). Sensors with a TEDS chip also enable automatic parameterization at the measuring amplifier.

What protection ratings (IP classes) are available for the force transducers?

Most standard models are designed for industrial use and achieve protection ratings of IP65 to IP67 (dustproof, protected against water jets and temporary immersion). Hermetically sealed versions made of stainless steel achieve IP68 and are suitable for underwater, cleaning, and outdoor applications under harsh conditions. Certified versions are available for use in potentially explosive atmospheres (ATEX/IECEx). The exact IP rating can be found in each product data sheet; interfaceforce® eK is available upon request to advise on application-specific selection.

How often should a force transducer be recalibrated?

There are no legally mandated intervals; however, ISO 9001, IATF 16949, and industry-standard quality assurance systems recommend annual verification. In practice, the interval depends on the intensity of use, environmental conditions, and the required measurement uncertainty. In safety-critical applications or after mechanical overload events, immediate recalibration is recommended. The interfaceforce laboratory performs manufacturer-independent recalibrations with short turnaround times – even for sensors from other manufacturers.

What is TEDS and what advantages does it offer?

TEDS (Transducer Electronic Data Sheet, IEEE 1451.4) is an electronic data storage device integrated into the sensor or connector that automatically transmits calibration data and sensor characteristics to the measuring amplifier. This eliminates manual input and parameterization errors when replacing sensors – the measurement setup is ready for operation via plug-and-play. The IFFDA93 handheld device and other measuring amplifiers from interfaceforce® eK support the TEDS standard and enable quick, error-free commissioning, even with frequent sensor replacements.

What are parasitic forces and how do they affect measurement?

Parasitic forces are unwanted shear forces, bending moments, or torsional loads that act on the sensor simultaneously with the actual measuring force and can distort the result. Even an angular deviation of 5° in the load application causes a systematic error. To minimize parasitic influences, interfaceforce® eK recommends using rod ends, pressure load buttons, and mounting plates – all available as accessories. The interfaceforce® eK team provides support for sensor selection and installation advice upon request.

What are the delivery times and can I order small quantities?

Standard models from Interface Inc. that are in stock are available for immediate delivery. Custom designs and customer-specific receivers are manufactured upon receipt of order; thanks to rapid prototyping, initial samples are often available within a few weeks. There is no minimum order quantity – orders are possible starting from a single unit. Inquiries and orders can be made via email (info@interfaceforce.de), telephone (+49 8022 271667), or the contact form on the website.

Use of sensor technology for prosthetic developments

We are witnessing the beginning of a new era in the design and functionality of prosthesesAdvances such as 3D printing, AI-driven prosthetics, and advanced neural interfaces are transforming the possibilities for amputees. These innovations enable the creation of highly customized devices that fit better, provide greater comfort, and enable an intuitive user experience.

Sensor technology supports many medical devices and improvements in healthcare. Interface sensors are used in the development, design, and testing of modern prostheses , resulting in a more natural and intuitive user experience. By accurately measuring weight, force, and torque, these sensors provide crucial real-time feedback.

An important aspect of these advances is the accuracy of data from measurement sensors. These sensors can be used in product development and invention, allowing for customized customization. For example, miniature load cells in a test for a prosthetic hand can detect the magnitude of the applied force, preventing objects from slipping or being crushed.

Integrating small sensors, such as load-button load cells or our SuperSC , which is the size of a quarter, can help test how prostheses can dynamically adapt to user movements and environmental conditions. Force sensors used in leg prostheses can measure resistance and flexibility when transitioning from a smooth surface to uneven terrain to ensure stability and reduce the effort required by the user.

A medical research company affiliated with Interface wanted to determine how a prosthetic foot would react to loading in different positions. Interface's 3A120 3-axis force sensor was installed between the leg socket and the prosthetic foot. The 3A120 was then connected to the BSC4D multi-channel bridge amplifier and the PC interface module. Data was recorded for the X, Y, and Z axes. The customer was able to review the results and identify premature flattening and dead spots during foot use. They can now make improvements to the design.

Another important advance is the support provided by sensor-assisted prosthetics for therapists in refining patient movements and optimizing rehabilitation plans. Furthermore, device improvements are supported and remote progress monitoring is enabled, promoting personalized and adaptable therapy. Wireless data acquisition systems streamline testing setups and enable real-time monitoring during rehabilitation.

Specific applications of testing and measurement in prosthetics

Precise force and torque measurements are essential at every stage of a prosthetic's life cycle, from initial research and development to daily use. Here are some application examples.

Controlling grip force using miniature load cells integrated into the prosthetic hands allows precise control of grip force, allowing users to handle delicate objects without damage and firmly grasp heavier objects.

Gait analysis and optimization benefits from load cells and multi-axis sensors embedded in prosthetic feet and ankles. They provide critical data for analyzing gait patterns, identifying imbalances, and optimizing gait for smoother, more energy-efficient movement. This is especially important for adaptive limb modifications.

Improving balance and stability is more accurate when sensors throughout the prosthesis help maintain balance and stability, especially on uneven surfaces or during dynamic activities.

Tactile feedback for object manipulation requires advanced sensory feedback systems, often including ultra-miniature force sensors, that allow the user to “feel” the texture, shape, and weight of objects, greatly improving dexterity and manipulation capabilities.

Materials testing requires high-precision load cells to evaluate the strength, durability, and fatigue life of new prosthetic materials, including advanced composites and 3D-printed components.

Validation of the individual prosthesis design requires accurate force and torque measurements to check the performance and fit of the custom-made prostheses to ensure they meet the specific needs of the patient.

Biomechanics researchers use precision force sensors as indispensable tools for analyzing human movement and the interaction between the body and prosthetics, leading to more natural and efficient designs. Torque transducers help measure rotational forces, which are essential for optimizing the smooth and natural movement of robotic prosthetic joints.

Predictive maintenance of prosthetic components benefits from the use of load cells for monitoring as they can detect subtle changes in component performance or loading, enabling predictive maintenance and extending the life of the prosthesis.

Prostheses must be tested for extreme stresses that can occur during falls, accidents, and athletic activities. Fatigue testing of prosthetic components determines their expected lifespan under normal usage conditions. A static load test uses a fatigue -resistant SSMF Type S load cell attached to hydraulic actuators to apply and measure cyclic loads. During the static test, loads are applied to the specimen, with the load cell signal used as force feedback control for the testing machine. In a fatigue test, the force is repeatedly switched on and off by the actuator to simulate activities such as walking. Tilt tables can be used to apply forces at different angles, thus simulating the heel-toe motion of walking or running.

Products for prosthetic innovations

Interface specializes in high-precision force measurement solutions, making our products particularly well-suited for integration into advanced prosthetic systems. Our robust and reliable sensors are ideally suited to meet the stringent requirements for diverse measurement capacities, accuracy, durability, and compact size in prosthetic applications.

A medical device manufacturer developed a new design for an artificial hip joint and needed to verify the load consistency and durability of its design. An Interface 6A40B series 6-axis standard force transducer was mounted on the manufacturer's test machine, where loads were applied to simulate real-world use. Our BX8-AS BlueDAQ series data acquisition system was connected to the sensor to collect data for analysis, which will help inform design changes and improve the durability of the artificial hip joint.

Products commonly used in the development, testing, and use of prostheses include:

Mini load cells:
load button load cells
S-type load cells
LowProfile load cells
Multi-axis load cells
Torque transducer
Wireless telemetry systems
Measuring instruments and amplifiers
Data acquisition systems

Interface excels at providing products that support the continuous growth, evolution, and customization of the prosthetic medical sector. The broad spectrum of applications in prosthetic research and development, testing, and feedback is ideally suited to Interface's highly accurate and reliable force and torque measurement solutions, helping to create a future where prosthetic limbs offer unparalleled functionality, comfort, and a truly natural feel. Contact our team for more information on your design and testing needs.