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Understanding Load Cell Temperature Compensation

The performance and accuracy of a load cell is affected by many different factors. When considering what load cell will work best for your force measurement requirements, it is important to understand how the impact of the environment, in particular the temperature impact on output.

An important consideration when selecting a load cell is to understand the potential temperature effect on output. This is defined as the change in output due to a change in ambient temperature. Output is defined as the algebraic difference between the load cell signal at applied load and the load cell signal at no load. You can find more detailed information in our Technical Library.

Temperature affects both zero balance and signal output. Errors can be either positive or negative. To compensate for this, we use certain materials that are better suited for hot or cold environments. For instance, aluminum is a very popular load cell material for higher temperatures because it has the highest thermal conductivity.

In addition to selecting the right material, Interface also develops its own proprietary strain gages, which allows us to cancel out signal output errors created by high or low temperatures.

In strain gage-based load cells, the effect is primarily due to the temperature coefficient of modules of elasticity of the force bearing metal. It is common in the industry to compensate for this effect by adding temperature sensitive resistors external to the strain gage bridge which drop the excitation voltage reaching the bridge. This has the disadvantages of adding thermal time constants to the transducer characteristic and of decreasing the output by 10%.

Our load cells are temperature compensated for zero balance. By compensating for zero balance, we can flatten the curve in the relationship between temperature and zero balance. An uncompensated load cell has a much more severe curve, which ultimately affects accuracy and performance.

Interface offers thousands of load cell designs, standard use and for hazardous environments. For instance, rocket engine tests subject our load cells to extremely high temperatures. For use in various maritime industry projects, they can be used in very cold coastlines and even submerged in cold water. No matter where you are, environment influences the load cells performance.

If you are concerned about temperature, Interface provides specifications for every load cell we manufacture. The Interface specification datasheet, as see referenced here, is available for download by product. It always includes all the necessary data required to understand the load cell’s ability to perform at the highest-level including compensation range, operating range, effect on zero balance and effect on span.

One thing that is also unique about our products is that while most competitors only compensate for hot temperatures (60 to 160 degrees Fahrenheit), Interface covers both hot and cold thermal compensation from 15 to 115 degrees Fahrenheit, including adjust and verify cycles.

Be sure to tune into Load Cell Basics, where Keith Skidmore discusses temperature compensation.  He notes during this informative presentation that if the temperature is changing during a test that can affect the zero and the output of the load cell. How much effect depends how much temperature is changing and how well the load cell is compensated against the errors, which can be either positive or negative. Good news is they are repeatable from test to test so if you have large temperature swings you can characterize the system and then subtract out the shift if you know the temperature effect on zero.

Interface Application Engineers are available to answer questions regarding the effect of temperature on force measurement data, or the different ways we can help design a solution to compensate for your environment.

Quality is Top Reason Customers Choose Interface

In our latest customer feedback survey, we asked those that rely on Interface why they buy from us. The overwhelming top response was product quality. One of the trademarks of Interface is ensuring that our products meet not only the demand of what is needed in the market for measurement sensors, but that the precision, accuracy, and quality of everything we build is market leading. Best in class.

Our customers drive Interface innovation. We are continuously looking at trends, special requirements and future outlooks to determine what solutions can meet today’s requirements and those in the future. It was noted in the survey that customers depend on Interface for this expertise and experience. That is why it is central in our business strategy and key for Interface’s success to ask, listen and learn from those that rely on our force measurement solutions in their businesses.

A hallmark to our semi-annual survey is the Net Promoter Score (NPS) question that is designed to measure loyalty. We asked again in this latest Spring 2021 survey, “How likely is it that you would recommend Interface to a friend or colleague?” Respondents are then asked to rate their response by selecting 0-10 with 10 being extremely likely and 0 not at all likely. The percentage of those that select 9 or 10 are considered promoters of the Interface brand. Anyone that scores 6 or below is considered by NPS standards to be a detractor. The percentage of promoters minus the percentage of detractors are gives you an NPS score.

We are very excited to announce that Interface’s current Net Promoter Score is +73.

The founders of NPS note that outstanding companies in their class average between a +30 to +50. We are honored by the recognition coming directly from our customers.

“This is a great result! We appreciate the recognition of our team member’s hard work to generate such customer satisfaction and loyalty. Global brands recognized around the world and who are famous NPS power users rarely report scores as high as Interface. We are honored to have such loyal customers, as seen in an outstanding +73 NPS. Remarkably, this came during a period where the customers’ most recent experience likely was influenced by the pandemic strain.” Greg Adams, CEO

We learned from our customers when we asked, “What are the most important reasons why you choose to buy from Interface?”, that product quality matters most, followed next by calibration and repair services, accuracy specifications, experience working with Interface and brand reputation. We also looked at trends in future product demands and the ability to buy online through our QS48 online shopping service.

Our customers were very forthcoming in their preferences for technical support, with phone and email taking top positions. This was followed by using our technical library, video demonstrations and numerous product and technical manuals.

We also gained great insights from our customers when we asked, “How can we improve your overall experience working with Interface?”  All feedback matters to us. It’s what we gain through this transparent and open process that we know where we can look to improve. In fact, we are determined to look at every opportunity presented in the survey to make operational improvements that benefit our customers in all areas from design to shipments.

“Our team performance demonstrates the winning position we are all committed to at Interface. Customer experience is central to what we do and it’s our focus to continuously exceed expectations. As great as this score is today, the better news is that we have the opportunity to improve further and define our future as the market leader by delivering the best for our customers.” Greg Adams, CEO

Our last question in the survey, we asked, “How satisfied are you with Interface and your customer experience?” and we learned that 98% of our customers are satisfied and 83% are very or exceedingly satisfied. We appreciate all those that provided their candid responses in our Spring Customer Satisfaction and NPS Survey. Our work continues to make sure what we do goes above and beyond and delivers on our promise to exceed expectations.

 

Load Cell Basics Sensor Specifications

When selecting a load cell, it’s critical to understand the major factors impacting sensor accuracy. These factors are determined by the materials and components used in the construction of the load cell, the calibration, instrumentation, the accessories such as cables, and mounting installation. Each must be considered in the specific use cases for the load cells.

During our virtual event, Load Cell Basics, applications expert Keith Skidmore detailed everything you need to know about load cells and how to choose the right load cell.  First, Keith highlighted four vital application considerations:

Mechanical – Dimensions and Mounting

Electrical – Output and Excitation

Environmental – Temperature and Moisture

Performance – Accuracy and Thermals

Taking a deeper dive into performance, an important consideration when selecting your load cell are the sensor specifications and how they impact accuracy. The sensor specifications relate to the max error of various parameters. The specifications are always included in product spec sheets and are expressed using the following values – %FS, %RO, %, %/°F, time-related. Specifications listed relate to the max error for accuracy and temperature.

Interface provides all sensor specification data for our load cells in the product datasheets found on each product page for easy download.

The information we provide for every load cell typically includes:

Accuracy:

  • Static Error Band
  • Non-linearity
  • Hysteresis
  • Non-repeatability
  • Creep
  • Side Load Sensitivity
  • Eccentric Load Sensitivity

Temperature:

  • Compensated Range
  • Operating Range
  • Effect on Zero
  • Effect on Span

Further definitions can be found in our online technical glossary.  Here are a few that we highlighted in the Load Cell Basics webinar.

Static Error Band: A band encompassing all points on the ascending and descending curves centered on the best fit straight line. It is expressed in units of %FS.

SEB Output: The output at capacity based on the best fit straight line.

Non-repeatability: The maximum difference between output readings for repeated loadings under IDENTICAL LOADING AND ENVIRONMENTAL CONDITIONS. In practice, there are many factors that affect repeatability that ARE NOT included in the non-repeatability specification. It is normally expressed in units of %RO.

Non-linearity: The difference in the output from a straight line. It is normally expressed in units of %FS.

Hysteresis: The difference in the ascending versus descending curves. This is normally expressed in units of %F.

Understanding these factors and the maximum error for your specific project is critical to selecting a load cell and getting the best possible data out of it.

To learn more about sensor specifications for load cells, review the product specs on each datasheet or in our product catalogs. For additional help, call to speak with our application engineers at 888-557-2533.

To view additional online events, please go to our events page.

 

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.

Tension Links 101

A tension link load cell is commonly used in lifting, both for short and long distances, and weighing applications. This type of load cell sensor generally has capacities ranging from 2.2K lbf to 1.1M lbf (5 to 500 metric tons). All tension links are available in custom versions and large capacities based on the customer’s project requirements.

Interface’s Tension Link series is manufactured from high tensile aluminum and stainless steel. Matched to shackle sizes, the load links have a rugged design for uses in harsh environments on the surface and in water. The tension links are environmentally sealed to IP65, IP66 or IP67. There are higher ratings available upon request.

A major benefit of Interface tension links is the option for custom designs in dimensions, ratings and capacities. The tension links are easy to install and are highly accurate.  They are compact in size and light weight. Another benefit is the options available, which include standard, wireless and self-indicating, giving the operator a variety of application use cases for quick measurement readings.  Self-indicating tension links have a built-inaudible alarm, which can be set by the operator to warn when an applied weight or force is met.

Often, customers will integrate the tension links with an Interface Crosby styled load shackle for robust applications that require accurate and reliable force measurement used for lifting, weighing, hoisting or towing apparatus that need sensors for safety and monitoring.

Wireless options are growing in acceptance for all types of uses. Interface provides wireless tension links that are compact and reduce the overall product weight based on the casing used to house the small alkaline batteries, which can be easily accessed by removing the telemetry housing cover while the internal electronics remain completely sealed. The antenna is also internally mounted, protecting it from accidental damage during use and handling, which is ideal for harsh environments.

Watch this discussion to learn more about the wireless features of the Interface Tension Links and Load Shackles.

Interface’s most popular tension links include:

WTSTL Wireless Tension Link Load CellDesigned for lifting applications requiring short or long distances. This product can transmit wirelessly up to 600 meters in distance (clear line of sight) to a handheld display or USB base station. Model WTSTL is available in capacities ranging from 11K lbf to 220K lbf (5 to 100 metric tons). Custom versions and larger capacities are available upon request.

WTSLTL Lightweight Wireless Tension Link – This smaller version ranges from 1 to 300 MT (2.2K to 661K lbf) and uses a lightweight aluminum construction, with an internal antenna and 1200 hours batter life using standard AA batteries.  It has high accuracy and uses license free 2.4GHz radio. There is an option to use this with telemetry and/or software for readout and reporting.

ISITL Self-Indicating Tension Link Load CellManufactured from high tensile aluminum to minimize weight, the ISITL is great for lifting and weighing in rugged or harsh environments.  The self-indication tension link load cell is ideal for mobile use cases.  It is simple to install and is matched to standard shackle sizes. They have a built-in display for applied weight or force in tons, kgs, lbs or kN. Interface can also offer a custom software to meet any specific application requirements for digital display or readouts.

ITL Tension Link Load Cell – This basic tension link can be amplified with 5VDC, 10VDC or 4-20mA Outputs. It can also be made to meet ATEX requirements. Model ITL is available in capacities ranging from 11K lbf to 220K lbf (5 to 100 metric tons). Custom versions and larger capacities can be requested at no additional charge, based on the exact specifications needed by the customer.

To learn more about our wide variety of load pins, load shackles and tension links, please visit www.interfaceforce.com/product-category/load-pins-tension-links-and-load-shackles/.

 

 

Understanding Uncertainty in Load Cell Calibration

In force measurement testing, accuracy is the most critical factor in ensuring the data you collect can help to identify challenges, failures and opportunities in the product design and development cycle. Here at Interface, we have mastered the art of load cell accuracy by employing a vertically integrated manufacturing process that allows us to control the development of our products most critical components.

Even the most high-end manufactured load cells and finely tuned components endure accuracy degradation over continued use. Therefore, we have also invested in equipment and talent with deep expertise in load cell recalibration, as well as offering gold and platinum standard calibration systems to customers. Recalibration is recommended on an annual basis, or of course, whenever our customers feel they need to confirm they are getting the right data out of their load cells.

One of the key factors of calibration and recalibration is understanding how to estimate practical uncertainty in load cell calibration. Measurement uncertainty is defined as an estimate of the range of measured values within which the true value lies or, alternatively, the degree of doubt about a measured value. In every application, there will be an uncertainty requirement on the force measurement. The equipment used to make the measurement must be traceable to a realization of the SI unit of force (the newton) within this required uncertainty.

Each application is different in terms of its uncertainty requirement. For instance, an application testing force in the aerospace and defense or medical sector will include a much more stringent uncertainty requirement than something like a commercial scale used to measure someone’s weight or food. It is critical to understand the uncertainty requirement on the application to ensure the force measurement device used is calibrated to handle the project.

How does one go about estimating uncertainty in load cell calibration? The first thing to understand is the GUM, a guide to the expression of uncertainty in measurement. This guide establishes general rules for evaluating and expressing uncertainty in measurement that are intended to be applicable to a broad spectrum of measurements.

Next, we have included a list of different considerations, as we measure uncertainty here at Interface. These factors will help guide you as you determine uncertainty for yourself. This list includes:

  1. Determine what parameter is to be measured and the units of measure.
  2. Identify the components of the calibration process and the accompanying sources of error.
  3. Write an expression for the uncertainty of each source of error.
  4. Determine the probability distribution for each source of error.
  5. Calculate a standard uncertainty for each source of error for the range or value of interest.
  6. Construct an uncertainty budget that lists all the components and their standard uncertainty calculations
  7. Combine the standard uncertainty calculations and apply a coverage factor to obtain the final expanded uncertainty.

It is also important to consider the different methods of load cell calibration. There are three different methods, and each has an approximate feasible expanded uncertainty. The different calibration methods include:

  • Direct dead weight – this method is the best for accuracy at 0.005% uncertainty, but it is slow, and the equipment is space inefficient.
  • Leveraged dead weight – middle of the road for accuracy at 0.01% uncertainty, and slow and space inefficient.
  • Hydraulic force generation comparison – this method has reasonable accuracy at 0.04% uncertainty and is also the fastest and most space-efficient option.

The final point is the sources of error in calibration. Error is defined as the difference between the measured value and the true value. There is a long list of different factors that can cause error and increase uncertainty. These factors may include drift, creep, misalignment, or environmental factors such as temperature. To compensate for this, it is important to understand the various formulas that can be used to find the true value based on the given measurement and the various factors for error.

To learn more about uncertainty and the different ways users can address uncertainty and overcome it, please give us a call at 480-948-5555, or visit our website to contact our Application Engineers.

Contributor:  LaVar Clegg, Interface

Source: NCLSI Measurement Training Summit 2014

Interface Differentiator is Proprietary Strain Gage Manufacturing

Interface products have been heralded for their accuracy, reliability, and quality for more than 50 years. We credit our vertically integrated approach to manufacturing as the most significant factor in our development of industry-leading force measurement products, meaning we control every part of the design, manufacturing and testing of our products before they are shipped to our customers.

The process for how we differentiate ourselves begins with Interface strain gages. By manufacturing our own proprietary strain gages here at our headquarters in Scottsdale, Arizona, we can optimize our load cells to a quality level very few providers can match.

Think of strain gages as the heart and soul of a load cell. These components power every aspect of the device and their quality dictates a significant portion of the load cells’ overall quality. In addition, customization of the strain gages is a critical factor in ensuring the load cell is meeting the specific requirements of a customer’s project.

The last point is critically important because Interface does not just provide one size fits all products. Yes, we have a large standard product line ready to ship. There are many times when we collaborate directly with our customers to understand their application and the challenges that may be present during a force measurement testing program or OEM design. This allows us to offer modified and custom products that are engineered to order.  Whether that comes in the form of an off-the-shelf product within our catalog of more than tens of thousands of options, or a new model using our strain gage technology to meet the needs of a unique application.

An example of our commitment to meeting customer needs is the way we develop our strain gages to compensate for temperature, an environmental factor that can drastically affect the accuracy of force data. Our strain gages are designed and manufactured to counteract the temperature characteristics of the modulus of the load cell structural material.

The benefit to this is that our load cells are temperature-insensitive and do not require modulus compensation resistors, ultimately producing a simpler and more reliable circuit with higher output signal. It also means no dynamic thermal mismatch errors from modulus compensation resistors which cannot be thermally connected with the load cell’s surface at the strain gage location.

In addition, our proprietary strain gages provide several key benefits. Included below are a few of the differentiators available with Interface strain gages:

  • A higher output of 4mV/V, while competitors provide 3mV/V or less, which provides superior performance, flexibility, and accuracy.
  • The ability to perform hot and cold thermal compensation, from 15˚ – 115˚F, while competitors typically only provide heat compensation (60˚ – 160˚F).
  • Eight strain gages per load cell compared to our competitors four gages, which provides superior compensation of eccentric loads to further minimize resulting errors.
  • Our strain gages also offer:
    • Higher signal-to-noise ratio
    • Higher resolution in precision measurement applications
    • Superior fatigue life

Another factor in the development of our strain gages is our expertise and knowledge of the manufacturing process. We have always developed our own strain gages going all the way back to 1968. Therefore, we have learned everything there is to know about it and can guarantee the quality of our load cells in any environment based on this tenured expertise and having manufactured and calibrated millions of force measurement devices.

To learn more about our vertically integrated manufacturing process and the various forms of product and system customization we offer, contact our specialized application engineers.

 

Interface Engineered to Order Solutions

Load cells and torque transducers come in many different capacities, sizes and capabilities. They are used in nearly every industry that manufactures any type of hardware device or component. From testing minute forces on miniaturized medical devices, all the way up to measuring force in the construction of enormous suspension bridges or even rocket engines. The point is, there is no one size fits all in the force measurement world when performance matters.

What makes Interface uniquely the leader and is a true differentiator in the force measurement industry is our ability to provide engineered to order solutions to meet our customer’s exact application requirements.

Innovation across multitudes of industries has provided the opportunity to be more creative in utilizing Interface proprietary technology and engineering talent in the development of new force measurement devices. More and more we find ourselves leaning on our experts using our proprietary strain gages and product designs to develop solutions that meet the needs of our customer’s unique projects and end-products.

Through our work on modifications and custom solutions, we have expanded our product offerings to more than 37,000 uniquely designed products spanning across 52 years of development. Once initiating as a custom solution, many of these products have made their way into our catalog as standard products based on growing trends and larger demands.

There is also another form of customization, or more accurately termed modification, that we are seeing more and more as Interface grows our engagement with OEM customers. We call this “engineered to order” solutions. These solutions are different from full customization and critical in serving our diverse customers.

Designers and builders of high-volume products may have opted in the past for simplistic testing technology that lacks consistency, quality, accuracy and reliability. As product failures or customer satisfaction wanes based on performance, OEMs are driven to find force measurement solutions they can depend on for precise measurement and performance. This is also indicative of the times we are in utilizing advancements in production, technology and even robotics to produce products.

It is essential for product makers and engineers to find reliable solutions for accurately monitoring and testing product performance in real-time. In short, they need sensor capabilities that meet their product manufacturing volume, safety requirements and overall robust product performance standards. This is very typical in industrial markets where OEM customers want to monitor machines in the moment and more accurately predict fatigue or when a machine will need to be repaired, reducing overall downtime and saving money.

To best serve OEM customers and testing engineers with premium and affordable force measurement solutions, Interface offers engineered to order capabilities for the masses. Engineered to order means Interface can deliver force measurement solutions from our massive catalog that are modified to meet the features and specifications that our customers require, while still retaining the premium accuracy, quality and reliability Interface is known for across every industry we serve.

Interface Application Engineers work closely with our customers to determine the exact specs their product requires and deliver a manufacturing plan that meets their volume, accuracy and reliability needs through an engaged process. We plan, coordinate and team together to build the right product, for the right time and right price. Most importantly, we can modify most of our products in our entire catalog, giving flexibility within a precision line of solutions.

OEMs, product designers, and testing experts do not need to compromise performance. Interface’s engineered to order process combined with our automated production lines allows us to provide the same great quality force sensor our customers expect from an industry leader.

Interface excels when we partner with our customers in the earliest phases of development to ensure we provide the best solution, based on size, capacities and performance capabilities. By sharing design plans, we can collaborate with our customers to provide the best outcome. Ready to engage our experts?  Contact us here.

Understanding One-Cell Force Measurement Systems

When it comes to load cells and force measurement systems used to test and validate product designs, the options for different configurations is nearly endless. In fact, Interface has tens of thousands of force measurement products in standard, modified and custom-made configurations.

In our recent post, Considerations for Steel, Stainless Steel and Aluminum Load Cells, we detailed materials used in load cell construction. These considerations are important based on the project specifications for accuracy, quality and reliability in test and measurement.

Similarly, understanding the system configuration is another critically important factor to setting up the correct test for receiving accurate data.  A simple system configuration used for less-complex testing is known as one-cell or single load cell system.  They are popular for performance and durability testing.

How do one-cell systems work and what are the benefits and trade-offs?

One-cell systems are developed by using a tension cell and mounting it through a rod end bearing and clevises. If the cell is properly oriented with the dead end going to the support, the only other major consideration for this system is the elimination or reduction of possible parallel load paths. This type of simple system is attractive to some testing engineers and product designers because it is cost effective and can provide very accurate measurements when using Interface precision load cells.  It is important that the load meets the criteria for the test system.

In this figure, it shows a high-impact one-cell system platform. This one-cell system can withstand the high impact of rough treatment from certain applications such as large drums, LPG tanks and more.

The downside to using a one-cell system is that the center of gravity of the load must be placed directly on the mark for the system to work properly. However, this can be accounted for by positioning the fences as shown in the high-impact one-cell platform diagram, so that the center of gravity is located properly when the application you are measuring is shoved up against fences.

The actual load at the center of gravity for your application will be factored by the lever arm (as shown below):

The one-cell system works simply because the location of the center of gravity is under control. If the force on the primary axis of the load cell bears the same relation to the location of the center of gravity and the load under all conditions, the scaling will be correct. Whether using a one-cell or two-cell system, the system must be designed to retain its integrity.

This has been a brief overview of a one-cell system, which is detailed in Interface’s Load Cell Field Guide.

To learn more about these systems and to determine if your application test can utilize the simplicity and cost savings of a one-cell or two-cell system, contact our systems experts and application engineers.