Posts

How to Choose the Right Load Cell

Load cells are used to test and confirm the design of hardware, components, and fixtures used across industries and by consumers. From the structural integrity of an airplane to the sensitivity of a smartphone touchscreen, there’s a load cell available to measure force. In fact, here at Interface we have over tens of thousands of products used in force measurement, for all types of different applications.

How do engineers and product designers go about choosing the right load cell for a specific application or testing project?

Have no fear, Interface has put together a short guide on choosing the load cell that is right for you. This blog will cover the basic questions to answer when selecting a product, as well the most important factors affecting load cell choice.  Be sure to watch the online video, Load Cell Basics, that highlights key factors of consideration when choosing the right load cell for additional insights.

The basic questions you need to consider when selecting a load cell include:

  • What are the expected loads? What is the minimum and maximum load you’ll be measuring?
  • Is there any potential for higher peak loads than what you intend to measure? What are these expected peak forces?
  • Is it tension, compression, or both?
  • Will there be any off-axis loads? If so, what is their geometry? Do you want to measure them too?
  • Will it be a static, dynamic or fatigue measurement?
  • What is the environment in which you’ll be conducting your test? Will the load cell need to be sealed?
  • How accurate do your measurements need to be? Do they need to be at the highest accuracy of ±0.02-0.05% or within ±0.5-1%?
  • What additional features, accessories and instrumentation does your application require to complete a test?
  • Do you need standard electrical connectors or customized options? What about additional bridges or amplifiers?
  • How are you planning to collect and analyze the data output from the load cell?

Next, these are the most important factors affecting accuracy, which will have a heavy influence over the load cell you choose. It’s important to understand how your application and the load cell will be affected by each of the factors, which include:

  • Mechanical – Dimensions and Mounting
  • Electrical – Output and Excitation
  • Environmental – Temperature and Moisture

One of the most important factors in choosing the right load cell is understanding how it will be mounted for testing or as a component within a design. There are a wide variety of mounting types including threaded connections, inline, through hole or even adhesive. Understanding the mounting type that suits your application is critical to getting the correct data because a poorly mounted load cell will distort the results and can damage the load cell.

The mounting process also requires you to understand which direction the load is coming from, in addition to any extraneous loads that may be present. The load cell mating surface is also an important factor. For example, when using our LowProfile® load cells without a pre-installed base, the best practice is to ensure that the mating surface is clean and flat to within a 0.0002-inch total indicator reading and is of suitable material, thickness, and hardness (Rc 30 or higher). Also make sure that bolts are torqued to the recommended level.

If you’re conducting a fatigue measurement, it’s also important to address the frequency and magnitude of load cycles with your load cell provider. Factors to address include single mode versus reverse cycles, deflection versus output resolution, and material types. Interface offers a wide variety of fatigue-rated load cells that are perfect for these types of applications.

Another consideration in choosing the right load cell is the electrical signal. Load cells work by converting force into an electrical signal. Therefore, it’s important to understand the electrical output type necessary for your application, which could include millivolt, voltage, current or digital output. You can find the excitation voltage data on our website for each of our load cells. Additional considerations include noise immunity, cable length and proper grounding.

The environment is also a critical factor in ensuring accurate performance of your load cell. Interface provides load cells in a variety of material types including aluminum, steel, and stainless steel. Each material has a variety of properties that make them more suitable for different environments. For a more in-depth perspective on the different strengths and weaknesses of materials, please read our blog titled, Considerations for Steel, Stainless Steel and Aluminum Load Cells. For applications where load cells need to be submerged in liquid or enter an explosive environment, we also have a variety of harsh environment and IP rated load cells, in addition to load cells suitable for high humidity or splash resistance. Learn more about our intrinsically safe load cells here.

Learn more about choosing the right load cell in these online resources:

WATCH: Load Cell Basics with Keith Skidmore

WATCH: How to Choose a Load Cell with Design Engineer Carlos Salamanca

READ: Load Cell Field Guide

VISIT: Interface Technical Library

To learn more about choosing the right load cell for any application, connect with our applications engineers about the force measurement needs for your next project at 480-948-5555.

Force Measurement Accessories 101

When purchasing a new piece of force measurement technology, it is equally important to consider how you will accessorize it to optimize its utility.  Just like whether you’re wrapping your brand-new smartphone in a protective case to protect your asset or outfitting your new vehicle with top of the line wheels or smart devices to personalize it for your exact needs, accessories are essential to getting the most value out of your investment. This is no different in test and measurement applications.

Accessories ensure you get fully functional and accurate use of your force measuring equipment.

Interface provides the most accurate and reliable force measurement load cells and torque transducers on the market. We also supply vital accessories to pair with our products, including cables, adapters, load buttons, mating connectors, rod end bearings, and TEDS. Our accessories are high-quality components and utilize our stringent processes to ensure your Interface products perform to meet their published specifications utilizing Interface accessories.

Here is a quick overview of why you should consider certain accessories based on your application, along with some of the products we offer to properly accessorize and optimize the performance of your force measurement components.

Why Would You Need Force Measurement Accessories?

Accessories assist with the reliability and performance of load cells and torque transducers. They can also help certain products adapt to various applications. There are a few questions we ask our customers to consider when purchasing a load cell, transducer or other Interface test and measurement products.

  1. How and where is the Interface product connecting to your application?
  2. Are adapters necessary to make the product fit your application?
  3. Are you mounting the device to a hardened flat surface?
  4. How will you be monitoring the performance of your application?

These type of questions are an important step to determine the right accessories for each application, or if a custom accessory is necessary for your testing program. Our experienced Application Engineers can work with you to determine which accessories you need.

Interface Accessories

Cable Assemblies – We provide high-grade cables and connectors to ensure the maximum performance of force and torque systems. This includes standard and custom length shielded cables for connecting transducers to instrumentation.

Calibration Adapters – Our off-the-shelf and custom calibration adapters greatly improve and maintain transducer accuracy. Interface uses high-grade alloy and stainless steel, heat treatments and quality machining practices to ensure our adapters meet your performance needs.

Clevises – We provide high-grade clevises that will perform in your application as needed while maintaining the level of performance you expect from our products. Our clevises are precision machined to ensure performance, reliability, and durability.

Jam Nuts – In order to ensure strength and performance, jam nuts are utilized to maintain a tight bond between the application. We manufacture our own high-performance jam nuts for flat, parallel surfaces in multiple thread sizes.

Load Buttons – Load buttons are used for Interface LowProfile™, S-Type and Mini Beam Load Cells to convert a universal cell to compression only.

Mating Connectors – To match interconnects between load cells and instruments we provide high-grade, off-the-shelf and custom mating connectors to guarantee the performance of your readings are not compromised by a defunct connection.

Mounting Plates – Mounting is a critical factor in the accuracy and durability of force measurement tools. Our mounting plates are made from the best grade alloy and stainless steel and are machined to the tightest specifications. This ensures the load is properly distributed over the foundation of the supporting structure and provides a prepared surface for the load cell. Mounting plates eliminate the requirement for expansion assemblies in most installations.

RCAL Resistors – Interface RCAL Resistors are high precision components that provide an effective method for checking the calibration of a load cell system in the field or when a means of applying actual forces are unavailable.

Rod End Bearings To reduce alignment errors in tension applications, Interface provides high-grade Rod End Bearings that help couple your load cell to your application solution while maintaining performance.

Thread Adapters – Thread adapters provide flexibility to users when workings with male and female threads of differing sizes. Our thread adapters are manufactured with the best practices to ensure the performance of your transducer is maintained when attached to your force transducer application.

Transducer Electronic Data Sheet (TEDS) – Interface’s TEDS option provides a force or torque transducer with electronic identification, allows a sensor or an instrument to be “Plug and Play Ready”, meets IEEE 1451.4 Standard for Smart Transducer Interface and is available on new or existing sensors.

From top to bottom, Interface’s goal is enabling our customers to get the most out of their force measurement device. By combining our industry-leading products with our top-of-the-line accessories, you are certain to get the greatest value in your precision-based application test. For more information on our wide variety of standard and custom accessories, click here.

For additional information about the range of accessories available along with valuable tips about cables, TEDs, and mounting plates read or download the brochure below.
Accessories Brochure