Load cells play a crucial role in various industries, such as aviation, health, transportation, farming and manufacturing, by accurately measuring and monitoring weight. Choosing the right load cell for a given application can be challenging without an understanding of its specifications.
From capacity and accuracy requirements to environmental conditions and calibration considerations, all of these factors must be carefully evaluated.
This comprehensive guide will walk you through the basics of load cells, key specifications, and industry-specific considerations, ultimately helping you make an informed decision when selecting a load cell.
Common Types of Load Cells
Let’s start by exploring the fundamentals of load cells and their common types.
Load cells are specialized sensors designed to measure force or weight by converting mechanical stress into electrical signals. They are essential components in various industries, playing a critical role in ensuring accurate and reliable weight measurements for numerous applications.
There are several common types of load cells, each with unique characteristics that make them suited for specific applications.
- S-Beam load cells are one of the most common types of load cells. They are typically used in industrial applications where they are exposed to heavy loads. They feature a unique S-shaped design that allows them to absorb large forces without deforming, making them ideal for high-capacity and extreme temperature applications. They are also suitable for use in harsh environments and can handle both tension and compression forces.
- Bending beam load cells are typically used in precision weighing applications, such as laboratory scales, ingredient dosing systems, and medical scales. They are highly sensitive and can accurately measure small weight changes. They are also resistant to shock and vibrations, making them ideal for high-traffic or harsh environments.
- Shear beam load cells are designed to measure load in both tension and compression. They are often used in weighing systems, such as platform scales, hoppers, and tank weighing systems, and are particularly well-suited for high-capacity applications. They are often constructed with aluminum or stainless steel for durability and corrosion resistance.
- Double-ended shear beam load cells are designed to measure force in both tension and compression, making them suitable for a wide range of industrial applications. These load cells are typically constructed out of stainless steel and feature a symmetrical construction with two load points at each end. This allows them to easily measure forces in both directions, providing accurate readings in both tension and compression. They are often used in weighing systems, tank weighing systems, and force measurement systems.
- Canister load cells are ideal for applications where space is limited. They are the oldest type of load cell and have been used in various industrial applications for many years. They have a cylindrical shape, making them ideal for confined spaces, and feature a single-point or multi-point design for enhanced accuracy and sensitivity. They are typically constructed out of stainless steel for durability and corrosion resistance, making them suitable for harsh environments.
Each type of load cell is designed for a particular purpose. Understanding the different types and the basics of load cells is the first step in selecting the right one for your specific needs.
Key Load Cell Specifications
To select the most suitable load cell for your application, it is crucial to assess your specific needs and requirements. Begin by identifying the purpose of the load cell, the type of force being measured, and the desired output. This information will guide you in choosing the appropriate type of load cell, as well as its capacity and accuracy.
Furthermore, load cell specifications are crucial in determining the performance and suitability of a load cell for a particular application. Some of the key specifications to consider include:
- Capacity: This refers to the maximum load that the load cell can measure. It is typically expressed in kilograms, pounds, or newtons and should be chosen based on the expected maximum weight being measured. Keep in mind that for most applications it’s best to select a load cell with slightly higher capacity than anticipated as this will provide some buffer against potential overloads. Also consider the minimum weight the load cell can measure. If your application requires measuring very light loads, it may be necessary to opt for a load cell with a lower minimum weight capacity or to seek a customized solution from a reputable manufacturer
- Accuracy: Accuracy indicates how close the measured value is to the true value. It is usually expressed as a percentage of the load cell’s full-scale capacity, and it’s critical to choose a load cell with an accuracy that meets your application’s requirements.
- Sensitivity: Sensitivity refers to the minimum detectable change in weight. A higher sensitivity load cell is ideal for applications where small weight changes must be accurately detected.
- Resolution: The resolution of a load cell is the smallest increment of weight that can be detected. Higher-resolution load cells provide more precise measurements but may also be more susceptible to noise and interference.
- Linearity & Non-linearity: Linearity describes the relationship between input (applied load) and output (electrical signal). A linear load cell produces a proportional output for a given input, ensuring consistent and predictable measurements. In contrast, non-linearity is the maximum deviation of the output signal from a straight line. It affects the accuracy of measurements, so it’s important to select a load cell with low non-linearity characteristics.
- Hysteresis: Hysteresis is the difference in output for the same input when approached from different directions (increasing or decreasing load). Lower hysteresis values indicate a more consistent performance, which is important for applications requiring repeatable measurements.
- Creep: Creep is the gradual and permanent change in output caused by prolonged loading of a load cell. It can affect the accuracy and stability of measurements, so it’s essential to select a load cell with minimal creep characteristics.
- Static Error Band: Static error band is an indication of the percentage of the full-scale load cell capacity that the load cell can measure accurately. It’s an important consideration in ensuring accurate measurements and should be chosen based on the application’s specific requirements.
- Environmental Factors: Load cells can be affected by environmental conditions such as temperature, humidity, potential exposure to water and dust, and ingress protection (IP) rating. It’s important to choose a load cell that can withstand the specific environmental conditions of your application to maintain accurate and reliable performance.
- Compatibility: Evaluating compatibility with existing systems and equipment is necessary to ensure seamless integration and ease of use. Consider factors such as mounting options, electrical connections, and compatibility with data acquisition systems or instrumentation. Ensuring that the load cell you choose can be easily incorporated into your existing setup will save time and resources in the long run.
Load Cell Calibration and Maintenance
Regular calibration through preventative maintenance is essential for maintaining the accuracy and reliability of load cells. It ensures that the measurements provided by the device remain accurate over time, compensating for potential issues.
Calibration methods may vary depending on the type of load cell, but typically include comparison to known weights, electronic calibration using reference signals, or using calibration software.
The frequency of calibration depends on various factors, such as the load cell’s application, usage frequency, and environmental conditions. Some industries may require more frequent calibration, while others can follow a standard schedule. Always follow the manufacturer’s recommendations or adhere to industry-specific guidelines to maintain optimal performance.
Identifying and addressing common issues is an integral part of load cell maintenance. Issues like drift, overload, and physical damage can affect the accuracy and overall performance of the device.
- Drift refers to the gradual change in the load cell’s output over time, which could be due to temperature fluctuations or other environmental factors.
- Overload occurs when the load cell is subjected to forces beyond its capacity, potentially causing permanent damage.
- Physical damage can result from mishandling, corrosion, or wear and tear over time. Regular inspection and timely resolution of these issues can ensure the longevity and accuracy of load cells.
Load cell applications include weighing scales, industrial automation, and force measurement systems, among others. Here are some examples of ways different industries use load cells:
The Aviation Industry
In the aviation industry, accuracy and reliability are crucial factors when selecting load cells. These devices must provide precise measurements for tasks such as weighing aircraft and monitoring baggage and cargo distribution. Load cells used in aviation applications must adhere to strict industry standards and regulations.
The Healthcare Industry
The health sector places a strong emphasis on precision when using load cells. Devices used in medical equipment, such as patient scales, pediatric scales, and wheelchair scales, must deliver accurate measurements to identify any health issues, such as nutritional problems, that may otherwise go unnoticed.
The Postal and Shipping Industry
Postal and shipping services often require load cells with high-capacity and high-resolution capabilities. These devices help ensure accurate weight measurements for packages, facilitating proper postage calculation and efficient sorting processes. Additionally, load cells in this sector must be able to withstand the demands of high-volume operations.
The Railroad Industry
For the railroad industry, load cells must exhibit robustness and durability in harsh environments. Devices used for monitoring axle loads, railcar weighing, and track scale systems must be able to withstand extreme temperatures, vibrations, and other environmental factors while maintaining accurate measurements.
The Trucking Industry
In the trucking sector, load cells play a vital role in achieving efficient load distribution and overall fleet efficiency. Reliable and accurate loads must be calculated to ensure safety, fuel efficiency, compliance with weight limits, and other key considerations. Load cells used for trucking applications should provide resistance against vibrations or impacts during transportation.
Importance of Choosing a Reputable Load Cell Manufacturer
A reputable load cell manufacturer plays a crucial role in ensuring the quality and consistency of the load cells you choose for your specific application. High-quality load cells, produced by well-established manufacturers, are built with precision and durability in mind, resulting in reliable performance and a longer service life. This ultimately translates to more accurate measurements, increased efficiency, and reduced downtime for your business operations.
In addition to the quality of the load cells, a reputable manufacturer will also offer excellent technical support and customer service. This can be invaluable when you require assistance in selecting the right load cell for your application, troubleshooting issues, or managing maintenance and calibration tasks.
Many reputable manufacturers also offer custom design and customization services. Partnering with the right manufacturer can prove to be beneficial in providing custom solutions that meet your unique requirements.
Choosing the Right Load Cell for Your Application
As we’ve explored in this beginner’s guide, understanding load cell specifications is crucial for selecting the right weighing solution for your needs. By considering these factors, you can make informed decisions that will help optimize your operations and ensure accurate, reliable measurements.
At American Scale, we’re committed to providing high-quality load cells, weighing solutions, and expert advice tailored to your industry and unique requirements. With our extensive experience and ISO/IEC 17025:2017 accreditation, you can trust us to guide you through the selection process and ensure your weighing system meets your needs.
We also offer scale service and calibration with 24/7 emergency service and routine preventative maintenance—making American Scale your one-stop-shop for all your scale shopping and servicing needs.
Don’t hesitate to reach out to our team at American Scale for assistance in choosing the right load cell for your application. Together, we’ll help you navigate the complexities of load cell specifications and find the perfect solution for your business.