Load Cell Types: Determining Which Load Cell You Need

Depending on the environment, such as operational or laboratory, there are different types of load cells. A load cell is the ideal application when you are looking to convert force into electrical output that can be measured. As a general rule, the accuracy of strain gauge load cells is between 0.03 and 0.25 percent. These load cells are typically utilized for the electrical measurement of strain resistance and experimenting stress analysis, and these are typically used in industrial applications. If optimal hygiene and safety are both vital and it is required for precision mechanical balances, then it is recommended to use a pneumatic load cell. Of course, a hydraulic load cell is a better fit in remote locations due to the fact that power supply is not necessary.

A Closer Look at the Different Types of Load Cells

Miniature Load Cells

Despite their minimum amount of space, these load cells actually perform at a very high capacity load. They have a low profile and are heavy duty. They are able to fully accommodate test benches, prototype structures, as well as industrial weighing applications. They usually include a cable connection and a twist-lock connector. Some miniature cells are available in metric configurations, which range from between 0 and 100 as well as 0 and 50,000 Newtons. Some of the most popular features with miniature load cells include high accuracy, built-in load buttons, stainless steel construction and the well-known 5-point NIST calibration that is completely traceable.

Strain Load Cells

For static and dynamic measurement, the most accurate and suitable load cells. In order to determine the strain, you will need to measure the chance in resistance of applied force to the matrix carrier, which will be bonded directly to the surface. The adhesive bond and matrix carrier work hand-in-hand in order to change the resistance or transmit the strain to the grid. Matrix carrier and adhesive will dissipate the heat and insulate against any type of electrical noise, which tends to act as interference and modify readings. When it comes to static strain measurement, the Wheatstone Bridge Circuit Theory is very popular due to its sensitivity.

Beam Load Cells

These types of load cells are very low capacity, with a range between one and 500 kg. With benefits including cost efficiency, they tend to be used for weight applications and OEM force measurements. They are typically made from aluminum alloy and are single point or bending beam load cells. However, there are some heavy-duty shear beam cells that are made with carbon steel alloy that is nickel plated and corrosion resistant. The double beam and shear beam load cells can be used in multiple cell applications, including industrial process control and tank weighing. Bending beam or cantilever load cells are primarily used for dynamic weighing, force measuring or static weight operations.

Platform Load Cells

These types of load cells are hermetically sealed and are best suited for applications that require high accuracy and water tightness, including automatic weighing stations, industrial weighing and industrial food processing. Resistive load cells have an accuracy of +/- 0.02 % of full scale and are built with bonded foil strain gauges. These load cells provide off-center load compensation, which is ideal when manufacturing accurate scales. S-beam (S-type) load cells tend to receive compression output readings and are designed to offer optimal performance for versatile and compact units, tank weighing, hoppers and suspended loads.

Canister Style Load Cells

These load cells are hermetically sealed, water-resistant and best used for single and/or multi-weighing processes. They can accommodate some of the harshest environments thanks to the environmentally sealed heavy-duty sensors and are best suited for axial compression applications. These load cells are hydrostatically compensated, which means that they can be used in submerged operations, such as underwater platforms, marine weighing, on dry docks, and in pit flooding environments.

Tension/Compression Load Cells

These particular forms of load cells have a low profile and are very versatile thanks to their welded stainless steel design. When it comes to monitoring tension and compression forces, they are incredibly accurate. The industrial-type load cells have threaded load connections and are constructed to measure either compression or tension forces in some of the harshest industrial environments. The bi-directional units have a range between 25 and 10,000 pounds in a 2-inch diameter.

How to Evaluate Your Load Cell Selection

• Measurement Duration – With a Tare, short-term measurement duration; without a Tare, longer duration
• Output Requirements – Wireless, digital USB, analog mV/V, Digital RS232/RS485, 4 to 20 mA, 0 to 5V
• Measurement Speeds – 1 Hz, between 1 Hz and 100 Hz, more than 100 Hz
• Direction of Loading – Compression, tension, or a combination of both
• Percent of Accuracy Requirement – As a percentage of full scale output, or a percentage of reading
• Operating Temperature Conditions – Outdoor temperature, room temperature, well-controlled environment, or harsh environment with humidity changes and wide temperature range
• Options for Mounting – Unfastened mount or fastening sensor to each side
• Certifications Requirement – Trade applications: OIML or NTEP certifications, testing or measurement R&D certification or ASTM E-74
• Operations Cost – Bulk volumes or small quantities