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Strain Gage Design Under Eccentric Load WRSGC Presentation

By Ashlesa Mohapatra, product design engineer, Interface

In the global marketplace, Interface is well known as providing the force measurement industry’s most reliable and accurate products. One of the key reasons that Interface consistently earns this recognition is because we manufacture our own strain gages. Products engineered and manufactured at Interface use our proprietary strain gages, and each designed for the specific transducer model based on the application type and environment for use.

As an example of our dedication to quality and excellence in performance as it pertains to strain gages, I recently shared a technical presentation on the negative effects of eccentric load and how strain gage design can reduce these challenges.

Below is a brief recap of this presentation made to the attendees of the Western Regional Strain Gage Committee meeting that took place in Tempe, Arizona in October 2022. The summary explains why strain gage design can make all the difference in quality versus poor performance with load cells.

Interface redesigned the strain gages on one of our mini load cells, the LBSU Miniature Load Cell Load Button, also known as our ConvexBT – The Most Innovative Load Button Load Cell. Our goal in the redesign was to create more controlled and repeatable loading, in turn creating a more predictable output. Our research focused on strain gage designs for load cells where mechanical moment compensation is not feasible.

The main challenge with this initiative was overcoming the errors associated with eccentric loading by making the installation process smoother through a redesign.  This is difficult because strain gages are very small in size and therefore more difficult to work with, in addition they are extremely sensitive to the environment with factors like temperature, humidity, cleanliness and electric interference all potentially effecting performance.

Before diving into the redesign, I would like to touch on eccentric loading and the errors it will cause, as well as the varied factors in strain gage manufacturing that can lead to errors causing eccentric load. There are two types of eccentricity: loading and mounting. Eccentric load results from improper loading or mounting of the strain gage, which leads to off-axis loads and bending. This causes several problems including distorted measurement results, decreased load cell accuracy, and diminishing life of the load cell.

When a strain gage is mounted on the load cell incorrectly or gages are badly bonded, it will almost always be an error source and contribute to mounting errors. Also, when strain gages are not bonded to the load cell at appropriate temperature and humidity, it leads to bubbles under the gage. Chemical composition of the strain gage is critical, such as the adhesive between the foil and backing, based on the application in which load cell will be used in a lab, machine, or testing program.

With these factors in mind, we set out on a redesign continuous improvement project. The previous design of this products strain gages was rectangular in shape. So, when the load cell was loaded, eccentrically or not, the strain field would not pass through because of shape. Therefore, we began to look at other shapes for our strain gage design, ultimately landing on a circular “diaphragm” style strain gage that allow strain fields to pass through.

One of the features of this newly designed strain gage is the proprietary adhesive foil we used to adhere the foil to the backing. This adhesive provided a great deal of benefit including a lower modulus of elasticity making it resilient to adhesive failure, and the elasticity also allows for better flow.

Another feature is the full bridge gage pattern we used that provides three key advantages. This includes fewer solder joints and reduced risk for electrical shorts due to simplified wiring, reduced symmetry error, and consistent thermal performance.

One process improvement we wanted to point out was that in our calibration process we only used 5V excitation voltage. Most manufacturers use 10V to calibrate their load cells. Due to lack of thermal mass in the thin diaphragm design of our strain gage, the zero will shift due to high voltage and low poor heat dissipation with 10V. We use a 5V excitation voltage to calibrate these miniature load cells instead of the alternative to prevent overheating of the cell.

To further improve the design, we enhanced the inspection process. Our diaphragm gages are quality inspected for accurate mounting with visual and electrical testing. Visual testing includes checking for air bubbles under the gage, badly bonded edges, unreliable solder connections and flux residues. Electrical tests include checking for electrical continuity and insulation resistance.

We then moved our attention to the circuit board. Some manufacturers use a circuit board in the cable due to the limited space within the cell to improve zero balance zero balance and to better compensate for temperature. However, bending or moving this cable would put pressure on the board and shift the zero. Therefore, we elected to install an abradable compensation resistors inside the flexure instead of the cable. This keeps the compensation resistor close to the gages and is intimately bonded to the body of the sensor to improve the reaction time of the cell to temperature.

To evaluate and confirm that our design was superior, we assessed three different strain gage styles: the rectangular gages (discreet gages), patch gages, and our diaphragm gage. Each of the gage styles were placed on three different load cells and loaded at one degree centricity. This test was run at 45 degree increments eight times. The results showed diaphragm style provided more reproducible result under eccentric load compared to other gages.

This was an interesting undertaking that taught the project team a lot about strain gage design and eccentric load. What I took away from this experience, other than a superior design for our ConvexBT Load Button Load Cells, is that any commercially successful product has a strong process behind it. You also need to have a clearly defined process that includes a continuous improvement plan. Interface Minis are a popular product line that has been around for many years. As soon as a product like this hits a point of stagnation, it will lose its hold on the market. I am proud of our team’s ability to avoid stagnation by taking critical steps to improving the Mini product line, maintaining our reputation for having the best quality, accurate and reliable products no matter the capacity available for precision force measurement.

Western Regional Strain Gage Committee (WRSGC), a technical division of the national Society for Experimental Mechanics (SEM), was established to promote a free interchange of information about strain measurement techniques using strain gages.

Interface is a proud member and sponsor of WRSGC. Our engineers participate in the technical conferences, in both presentation and attendance. Interface’s Product Design Engineer Ashlesa Mohapatra presented at the event held in Arizona, October 17-19, 2022.

Force Measurement Installation Guides

Interface is a long-time provider of the world’s most accurate and reliable force measurement products. Our sensor and instrumentation solutions are used across industries to test and monitor everything from critical infrastructure and to advanced robotics. Innovators and engineers know that our quality is unmatched. However, any measurement device manufacturer nor superior quality of a product can save users from poor performance when making this one critical mistake, poor installation.

Proper installation is one of the absolute keys to reliable and accurate test data and successful measurement programs. This is true for any type of test and measurement protocol, in particular utilizing force measurement.

Preparing for any installation for any load cell force or weighing measurement system is dependent of the integrity of the physical installation, interconnection of the components, following proper performance of the system components, and calibration.

Installation success is such an important topic, we asked Interface engineers and application experts for their thoughts on the top reasons why proper installation is critical to a successful test or vice versa. They also shared helpful guidance on why improper installation can be so damaging.

  • Poor installation can lead to damaging the load cell, so to protect your investment follow the installation instructions that a accompany your product.
  • When we provide performance metrics on our product, it is based on our in-house calibration. When improperly installed, you will not be hitting the performance numbers you need during use.
  • Improper installation can cause overload which can not only damage the load cell, but also create unsafe working conditions.
  • Installation guides not only give you the proper installation techniques, but they also provide the correct order for installation.
  • And our favorite tip, and the most relatable, “Improper installation with ultimately lead to headaches!

Installation can also vary widely between load cells and other force measurement solutions. Each product has different processes depending on the mounting components, the application being tested or monitored, the environment in which the application is being tested or monitored, and more. It is important to carefully review any materials provided with the instrumentation and sensor.

Interface provides a wide variety of installation guides, instructions and technical support online. You can find these instruction guides by visiting our support installation and manuals option.

In addition, we have resources providing clear explanation on installation and its importance. Recently, our video and blog series titled, I’ve Got A Load cell – Now What? Part 6 – Usage & Best Practices, includes in-depth information on installation and mounting.

Mechanical Installation Tips

Once you have your load cell hooked up and your instrumentation scale, it is time to put it to work. You want to review the attachment, including thread engagement and mounting. If you are threading into the live end, the center hub on the low profile load cell, make sure you have enough threads engaging into the load cell itself. We recommend that you thread it into where the studs bottom out, then back up a half a turn. Next step is to preload tension load by about 130% of capacity and jam the jam nut. We want to ensure that we do not have any repeatability issues due to thread engagement of the flexure. If you cannot provide a preload, reference the torque values in the installation guide.

Mounting to Base, Structure or Plate Tips

  • Use Grade 8 or Better Hardware
  • Mount to Total Flatness of .002″
  • R30-33 Hardness Scale
  • Follow the star patter to proper torque values
  • Preinstalled Bases

Interface bases help in making integration to any assembly much easier. Interface manufactures bases with the same high-performance materials and specifications for hardness and flatness as our load cells. The bases offer threaded holes, which make it easier for mechanics like hydraulic actuators.

We also offer several references for troubleshooting. Two important considerations to review during set-up are the mechanical and electrical installation requirements.

Mechanical Installation Troubleshooting: Load cells not mounted in accordance with the manufacturer’s recommendations may not perform to specifications. It is important to review the mounting surfaces, hardware, and orientation during the installation.

Electrical Installation Troubleshooting: Proper load cell performance is depending upon the electrical system. The areas to inspect during any install are the connections, cables, settings of excitation voltage and loading of the bridge circuit.

We urge that to get the most out of your new load cell to reference the materials provided in the installation guides. If you have any questions, Interface is also here to help. Feel free to reach out to your local representatives and distributors or call us directly at 480-948-5555 to speak with an engineer to help solve your installation challenges.

LowProfile Load Cells 101

In the field of force measurement, load cells are defined by a set of specifications attributed to a configured shape and size of the flexure model. These models are engineered to meet requirements in weight, size, cost, accuracy, use life, rated capacity, extraneous forces, test profile, error specs, temperature, altitude, pressure, and materials.

Of all the flexure models available, the low profile load cell is the most common force measurement sensor model used for general test and measurement applications.

Did you know that Interface is known for creating the first low profile load cells more than 50 years ago? Our founder first introduced the low profile in 1969 and later trademarked as the first of its kind precision LowProfile® Load Cell by Interface. With this invention, Interface became with market leader of precision load cells. In fact, our 1200 Standard Precision LowProfile® Load Cell, designed for eccentric load compensated tension and compression, remains our most popular product today.

This pancake-style shear beam cell design is world-renowned for durability, accuracy, and performance. The LowProfile design resembles two shear beam cells end-to-end, exhibiting the stability of a doubled-ended shear beam and augmented by the fact that the circular design is equivalent to four double-ended cells. Thus, it provides stability in eight directions at the center point.

The LowProfile designs include a base, bolted to the flexure around its outside rim. The base is a flat surface, guaranteed to provide optimum support for the flexure. The use of a base ensures the exceptional performance in the Interface LowProfile series, as each load cell is built, evaluated, and calibrated with the base.

Advantages of all Interface LowProfile design include:

  • Higher output
  • Better fatigue life
  • Better resistance to extraneous loads
  • Shorter load path
  • Extremely low compliance with higher stiffness
  • Option for compression overload protection integral to the cell
  • Proprietary strain gages
  • Customization

One process step that is standard in the LowProfile series is the adjustment to extraneous load sensitivity. Although the design itself cancels out the built of this sensitivity, Interface goes one step further and adjusts each cell to minimize it even more.

The Interface LowProfile Series is available in compression-only, tension and compression and calibration grade. There are high and low-capacity options, flange-style, amplified, as well as fatigue rated models. Various features are available through hundreds of configurations to accommodate the wide range of testing profiles, such as connectors, wireless, additional bridges, and overload protection.

The LowProfile Series has three major classifications: precision, ultra precision and fatigue rated. The basic construction of all the cells in the series is quite similar. The major differences are in the number of shear beams and the number of gages in the legs of the bridge.

LowProfile Precision Series: Standard capacities of the precision low profile designs can measure up to 2M lbf. The gaged sensors in every load cell are individually inspected and tested and certified to meet our rigid standards. With greater stiffness, respectable static error band specifications and resistance to extraneous loads, this is Interfaces number one line of products.  The standard 1200 is by far the most sought after low profile today.

1200 Precision LowProfile Load Cell Standard Series features:

  • Proprietary Interface temperature compensated strain gages
    Performance to .04%
    High output – to 4 mV/V
    0.0008%/°F (.0015%/°C) temperature effect on output
    Low deflection
    Shunt calibration
    Barometric compensation

This 1200 Standard Precision LowProfile® Load Cell standard model is available through our QuickShip48 expedited delivery service. Click here to order now. For additional low profile capacities of the Model 1200 series, base options, connectors, bridge options and overload protection availability, go here for the specifications datasheet, model options, drawings and technical specifications.

LowProfile Ultra Precision Series: Engineers at Interface designed this series to meet the demands of sophisticated testing labs with precision performance in the critical parameters such as static error band, non-linearity, hysteresis, non-repeatability, and extraneous load sensitivity. The models in the 1100 Ultra Precision LowProfile® Load Cell are the most popular of this design.

LowProfile Fatigue Rated Series: This series guarantees fatigue life of 100 million fully reversed load cycles.  This series has tighter specifications on resistance to extraneous loads and offers stiffer compliance. Interface’s fatigue rated load cells typically have static overload rating of 300% in both tension and compression modes. Originally designed for aerospace testing, the Interface 1000 Fatigue-Rated LowProfile® Load Cell are the most used fatigue-rated low profiles.

Interface also provides very high-grade low profiles for calibration. The LowProfile Gold Standard Calibration Series: Interface sets the standard in precision load cells. The model 1600 Gold Standard® Calibration LowProfile® Load Cell are uniquely designed for calibrating other load cells to the highest levels of quality and accuracy used in test and measurement. The Interface Model 1600 provides both tension and compression in one unit. It also has the options for a second and third bridge, as well as overload protection.

1600 Gold Standard® LowProfile® Tension and Compression Load Cell Standard Series features:
• 0.01% creep
• High Output to 4 mV/V
• High-Precision Installed Base
• ±0.0008%/˚F Max Temperature Effect on Output
• Low Deflection
• Shunt Calibration
• Barometric Compensation
• Calibration Adapter
• 3-Run NIST Traceable ASTM E74 Calibrations
• 4% Lower Load Limit per ASTM E74

Low profile load cells are used for all types of testing. There are many options and designs available as standard models. We also provide engineered to order, custom and OEM solutions for all our load cells. As with all our standard load cells, we do offer various capacities, modifications, and custom options.

One thing that is for certain, the Interface LowProfile is a standard across the force measurement industry. They are common in testing rigs, designed in as components, often found in the best metrology labs throughout the world.  Industry leaders in manufacturing, aerospace, automation, food processing, medical and biosciences, energy and transportation choose LowProfiles for the meticulousness required in high-performance force measurement testing.

Low-Profile-Load-Cell-Brochure

Faces of Interface Featuring Sean Malone

In today’s Faces of Interface, we talked with Sean Malone who is responsible for calibrating and repairing our customer’s force measurement equipment. As our esteemed warranty coordinator, his important role requires extensive knowledge of force measurement technologies. This is because not only do we support the products we make, we also calibrate and repair force measurement products from a wide variety of other manufacturers.

Throughout his life, Sean has always had a propensity for working with his hands. Hi family owned a locksmith business, so he grew up to become very mechanically proficient. In fact, Sean worked for the 35-year family-run business for 25 years before the family decided to sell it. Sean also went to school at ITT Tech during that time and received his associates in computer networking and science.

After leaving the locksmith business, Sean investigated a new role where he could continue to work with his hands every day. This desire led him to Interface. He began his career at Interface as a repair technician in our production facility, then he moved on to become a calibration finalist, and the manager of the service department before settling into his current role as warranty coordinator.

His journey through Interface’s service department gave him a great deal of knowledge about the business and the ins and outs of a load cell. This allows him to perform his current role to the highest degree and aptitude. He’s also a great resource for questions and support for our team members and global network. His position today includes being a single point contact for service customers, performing root cause analysis, fixing load cells, calibrating them, and ensuring items sent in for services get back to the customer in premium working order.

Sean says that he’s caught his professional stride at Interface and really enjoys the fact that he is learning something new every day. He also remarked that the people he comes to work with make the job and the company that much more enjoyable. We’re glad to have you here too Sean, as you represent the best in ForceLeaders.

In his free time, you won’t find Sean anywhere else but at the golf course. Being an Arizona native, he has grown up with a passion for the U.S. golf capitol of the world and all it has to offer for an avid golfer. His skills in the sport also extend to a little bit of frisbee golf from time to time. All things golf, all the time. That’s the way Sean winds down.

We’re incredibly honored to have Sean on the team and his work is critical to keeping our customers products operating at the highest standards of accuracy and reliability, today and for many years to come.

To learn more about the outstanding team at Interface, check in to our blog each month for our Faces of Interface series.

Specifying Accuracy Requirements When Selecting Load Cells

When selecting a load cell, it is important that your selection matches the type of application use case. If it is for general test and measurement requirements, a load cell model and capacity may differ from a load cell you design into a product or machine.

The first place to start in your transducer selection process of a load cell is to identify what you want to measure and your tolerance in accuracy.

Other questions will define the type of load cell, capacity, and measured specs. Do you want to measure tension, compression only, tension and compression, torque, or something else like pressure? What are your cycle counts for testing? What is the amount of measurement range you require? How controlled will the force be, both in orientation and magnitude consistency?

Once you identify early characteristic requirements for how you use the sensor, it is easier to begin evaluating options to optimize measurement accuracy.

Several aspects impact the accuracy of a load cell measurement, including:

  • Sensor Specifications
  • Mounting configuration
  • Calibration type
  • Instrumentation
  • Cables
  • Uncertainty of calibration

Every load cell should have a detailed specification datasheet that outlines key performance factors by model and size.

This post begins in defining specifications for accuracy as outlined for every Interface manufactured load cell. These accuracy-related specifications include:

  • Static Error Band %FS – The band of maximum deviations of the ascending and descending calibration points from a best fit line through zero output. It includes the effects of nonlinearity, hysteresis, and non-return to minimum load.
  • Nonlinearity %FS – The algebraic difference between output at a specific load and the corresponding point on the straight line drawn between minimum load and maximum load.
  • Hysteresis %FS – The algebraic difference between output at a given load descending from maximum load and output at the same load ascending from minimum load.
  • Nonrepeatability %RO – The band of maximum deviations of the ascending and descending calibration points from a best fit line through zero output. It includes the effects of nonlinearity, hysteresis, and non-return to minimum load.
  • Creep % – The change in load cell signal occurring with time while under load and with all environmental conditions and other variables remaining constant. Expressed as % applied load over specific time interval.
  • Eccentric Load Sensitivity: ECCENTRIC LOAD – Any load applied parallel to but not concentric with the primary axis. Results in moment load. SIDE LOAD – Any load at the point of axial load application at 90° to the primary axis.

Interface load cells are designed for precision, quality, and accuracy. Though the ranges may differ in specifications slightly, most of the performance data will far exceed industry standards. As we always say, Interface is the standard for load cell accuracy.

We will be outlining additional impacts on accuracy in upcoming posts. If you have questions on any product and specifications, as to whether it is the right load cell for your use case, contact us for help.

Additional Resources

Contributing Factors To Load Cell Accuracy

Application Notes

Accuracy Matters for Weighing and Scales

Interface Ensures Premium Accuracy and Reliability for Medical Applications

Interface Accelerates Accuracy in Test and Measurement

Interface Presents Load Cell Basics

I’ve Got a Load Cell Now What? Episodes 1 and 2

I’ve Got a Load Cell Now What? Episodes 3 and 4

I’ve Got a Load Cell – Now What? Episodes 3 and 4

Continuing our review of the popular webinar series, I’ve Got a Load Cell – Now What?, we are detailing the third and fourth episodes. The focus of these two installments is documentation that you should expect with every load cell and the fundamentals of load cell output.

Digging into documentation is an important subject for anyone that is buying or using load cells for test and measurement. It is also a differentiator in the quality and type of manufacturer that makes your device. The details provided in load cell documentation validates the characteristics and performance, as well as experience and craftmanship used in the engineering and construction of your load cell.

When quality and accuracy matters, documentation and certification are critical verification evidence.

Load Cell Documentation: Datasheets and Calibration Certificates

Interface provides detailed datasheets for every load cell model number. On the top of the datasheet, the Interface model number precedes the description of the load cell’s primary characteristics, such as 1200 Standard Load Cell. The Interface Calibration Certification accompanies every sensor device we manufacturer and ship from our U.S. headquarters, confirming the final condition prior to release. Interface calibrates every load cell we make before it leaves our facilities as part of our performance guarantee.

INTERFACE DATASHEET FUNDAMENTALS

  • Features and Benefits
  • Standard Configuration and Drawings
  • Dimensions
  • Specification Parameters Based on Model and Capacity
  • Detailed Measurement and Performance Data for Accuracy, Temperature, Electrical and Mechanical
  • Options
  • Connection Options
  • Accessories

Special note for datasheet reviews, the models that use the same form factor are often on the same datasheet with varying capacity measuring ranges in U.S. (lbf) and Metric (kN) information.  All Interface datasheets are available for review and download for every product we offer, including load cells, torque transducers, multi-axis sensors, mini load cells, load pins and load shackles, instrumentation and accessories.

INTERFACE CALIBRATION CERTIFICATES DETAILSIQ

  • Model Number
  • Serial Number
  • Bridge and Capacity
  • Procedures
  • Input and Output Resistance
  • Zero Balance
  • Test Conditions: Temperature, Humidity and Excitation
  • Traceability
  • Shunt Calibration
  • Performance Test Data of Test Load Applied and Recorded Readings
  • Authorized Approval

The performance information detailed on the certificate is important for how it was calibrated, how it performed at release, system health checks and troubleshooting. Watch the episode #3 of I’ve Got a Load Cell – Now What? for additional information about datasheets and cal certs.

Fundamentals of Load Cell Output

Load cells are used in one of two ways, either universal (bipolar) or single mode (unipolar). Bipolar is for measuring tension and compression. Unipolar is for measuring either tension or compression. This use type will dictate what output you will get from the load cell. Most Interface load cells are a tension upscale device, which means you will get a positive output when it is placed in tension.

Standard load cells are usually unamplified mV/V ratio metric output. Interface does offer amplification signals for our load cells, which is a common request when pairing with a data acquisition system. In episode #4 of I’ve Got A Load Cell – Now What?, Elliot provides an example of mV/V ratio metric when using a 5000 lbf LowProfile Load Cell with our 9840 Instrumentation.

For questions about datasheets, calibration certifications or performance and capacities, please contact our application engineers.

ADDITIONAL RESOURCES

Interface 1200 Precision LowProfile Load Cell Series Product Highlight

Load Cell Basics Technical Q&A Part One

Load Cell Basics Technical Q&A Part Two

Understanding Load Cell Temperature Compensation

Load Cell Basics Sensor Specifications

 

Get an Inside Look at Interface’s Famously Blue Load Cells

Interface “blue” load cells have been utilized for millions of test and measurement projects and programs around the world.  Since the invention of Interface’s LowProfile® Load Cell, the world’s most popular pancake style load cell series has become a standard for testing engineers and lab technicians for more than five and half decades.  Today, Interface has more than 60 different types of Load Cells, including our line of Mini Load Cells.

Interface load cells come in capacities ranging from 1 lbf (500 gf) to 2 million lbf (9,000 kN). As a U.S.-based manufacturer, our extensive production and engineering facilities produce several shapes and sizes of our Interface load cells, as well as calibrate every model before it leaves our facilities.

Our expansive line of sensor models includes pancake and donut styled load cells in our LowProfile® Load Cell series and thru-hole load cells. Additionally, we offer canister, rod end, downhole, column, coil tubing, load buttons, and load washers. All of these models use Interface’s proprietary alloy strain gages to provide higher output, higher signal to noise ratio, higher resolution and superior fatigue life. This helps us build the most accurate and reliable sensors for test and measurement applications.

What makes Interface’s LowProfile Load Cells a top pick?

Here is a look inside our famous blue load cell, highlighting the top reasons Interface is selected for accuracy, quality and performance.

Interface’s load cell model that has the highest demand and usage is the 1200 Precision LowProfile series. They are used in all types of industry applications, from Material Tensile Testing to Aircraft Lifting Equipment Tests. It’s followed closely by the 1000 Fatigue-Rated LowProfile series and 1100 Ultra Precision Load Cell series.  Every series has multiple configuration and capacity options. For example, the 1200 series provides off-the-shelf model options including:

1200 Standard Precision LowProfile® Load Cell

1200 and 1201 Series 3-Wire Amplified Load Cell Universal or Compression-Only

WTS 1200 Standard Precision LowProfile® Wireless Load Cell

1200 High-Capacity Standard Precision LowProfile® Load Cell

1201 Compression-Only Standard Precision LowProfile® Load Cell

Every designed load cell can also be engineered-to-order or customized to unique specifications.

The accuracy of data, engineered designs, proprietary strain gages, comprehensive specifications, quality inspections, detailed certifications and multiple calibrations of every load cell to ensure performance make the top of the list as to why Interface is considered best in class.

Here is an opportunity to get another inside look at the Interface LowProfile Load Cell:

If you are interested in reviewing this insider’s view with SI measurements, go here.

Take a closer look at the advantages of Interface’s LowProfile Load Cell in this cutaway view.

LowProfile Cutaway

New Additions to Interface Product Catalog

Every month our team at Interface adds new technologies and solutions to our extensive product catalog.  This year, we’ve added several new force measurement devices and supporting instrumentation to use in test & measurement projects, as well to create complete systems.  The following highlight some of these new additions.

NEW INTERFACE PRODUCTS

The following products are the latest additions to our robust line of standard load cells and torque transducers offerings, along with several new instrumentation options available for pairing with different sensor models.

TORQUE TRANSDUCERS

AT105 Contactless Force Torque Transducer

Highly accurate and maintenance free, contactless, rotating, torque force sensor with digital signal transmission from rotor to stator.

AT104 Compact Size Force/Torque TransducerAT104 Compact Size Force Torque Transducer

Reliable and durable reaction torque force sensor that is ideal for testing in small places, it is non-rotating, often used with a very short axial length.

LOAD CELLS

IPCD Pressure Compensated Downhole Load Cell

Superior to hydraulically compensated wet load cells provides high accuracy, is maintenance free and pressure compensated up to 20,000 PSI and temperature compensated up to 350°F.

MBS Parallelogram Load Cell

The mini load cell is made of lightweight aluminum construction is available is capacities from 2.2 to 100 lbf (9.8 to 445 N).

WSSB Welded Stainless Steel IP68 Environment Protected S-Beam

Ideal for measuring both tension and compressive forces has standard metric threads at each end of the load cell designed to accept standard spherical seating rod-end bearings.

INSTRUMENTATION

9840TQ mV/V Input Torque Transducer Indicator

Provides a TEDS template 33 & 40 (3-point linearization) and is plug and play ready. It is IEEE1451.4 compliant with read and write capability with lbf-ft, lbf-in, N-m and mV/V measurement units.

BSC1 Single Channel PC Interface Module & Bridge Amplifier

A single channel 2.5 analog output, up to 10 mV/V input, 15-pin connector and USB powered and has graphing and logging software.

BSC2 Dual Channel PC Interface Module

Model offers 2-channels USB output, up to 10 mV/V input with two M12 connectors. It is USB powered and incudes graphing and logging software.

BX6-BT Portable 6-Channel High Speed Bluetooth Data Logger

A multi-channel amplifier with Bluetooth connection and data logger functions, which offers exceptionally many features in the smallest dimensions.

INF1-Ethernet TCP IP Single Sensor Weight Transmitter and Indicator

INF1 has a six-digit red LED display (8 mm height), space-saving compact design and four buttons for the system calibration.

INF4-EtherCat Two, Three, and Four Sensor Weight Transmitter and Indicator

INF4has a six-digit display in a compact design with four buttons for the system calibration, and a six indicator LED.

JB1100 4-Channel Advanced Signal Conditioning Transmitter Indicator and Junction Box

This is a multi-functional, compact 4-channel instrumentation solution ideal for PLC systems requiring weight data from load cells.

VSC2 Rugged Compact Vehicle Powered Signal Conditioner

This new model is a high accuracy precision differential amplifier designed for use in harsh environments with low thermal error and an operating range from -40 to +125 C.

When reviewing your options for instrumentation based on features such as type of output, required channels, added software, programmability, speed, logging and graphing capabilities, TEDS ready, and enclosures, be sure to utilize our new Instrumentation Selection Guide.

If you have technical questions or need assistance in choosing the right load cell or instrumentation, please contact our experts.  We are here to assist you.

Interface Calibration 101

Calibration of force and torque sensors is critical to receiving accurate data from measurement testing.  Calibration is the comparison of the instruments output against the known standard of measurement. For a load cell, it is the comparison of the load cell output against the standard test loads.

The calibration ensures the sensor is performing accurately and set for ideal output based on the capacity and configuration of the design. A standard calibration tests repeatability and linearity, which are both used to determine the accuracy. Calibration tests are run to identify any potential measurement errors caused by zero offset, non-linearity, hysteresis, non-repeatability, and shifts from zero.

The team of calibration experts at Interface are specifically trained to provide this specialized service as part of our quality and lab standard requirements of operations. Interface is ISO/IEC 17025:2017 and A2LA Accredited for Torque and Force Calibration in accordance with the recognized International Standard ISO/IEC 17025:2017.

Interface certifies all our load cells with accredited calibration before releasing the product for shipment. Certificate information includes tabulated measurement variables data, zero balance, computed nonlinearity and hysteresis, and traceability statements. We are often recognized as the most complete calibration certification in the industry

In a recent customer survey, we found that one of the most important roles that Interface force measurement solutions play is for our calibration services. This is due to the accuracy, reliability, and dependability over long periods of time of the load cells we manufacture and service.

Why Calibrate?

Calibration is important based on many different factors, including continued performance, safety, and compliance with ISO or industry specific standards. Interface’s standard recommended calibration interval is to recalibrate every 12 months. The frequency of calibrations should be determined by the following use case factors that may affect measurement accuracy:

  • Measurement quality and allowable tolerance range
  • Level of stress to which the equipment is subjected
  • Stability of past calibrations
  • Required measuring accuracy
  • Quality assurance requirements

Interface Calibration Services

Interface provides calibration and repair services on load cells and torque transducers, including devices made by other sensor manufacturers. In fact, Interface performs more than 100,000 calibrations every year. This includes new products as well as devices sent to Interface for recalibration and repair. Repairs include a complete evaluation of the device prior to repair and calibration upon completion.

In addition, here are some other benefits for choosing Interface as your calibration services partner:

  • ISO 17025 Accredited
  • Scheduled Repairs for Ongoing Inventory Management
  • Custom Calibration Services
  • RMA Tracking and Permanent Archive of Test Data
  • NMI Certified Gold and Platinum Standard Reference Load Cells
  • Interface Gold Standard Calibration Software Used for Data Collection and Analysis
  • Full-Service Machine Shop for any Mechanical Requirements

Calibration Services Process

The Interface calibration team consists of a team of professionals dedicated to an optimized calibration and repair process for timely management of our customer’s requests. We begin the calibration service process with our technical services group who manage the request and RMA process, in addition to evaluation and troubleshooting.

We evaluate all products at our headquarters with our team of experts. The sensor goes through a thorough inspection process to identify any necessary repairs and to ensure device is in working condition in preparation of a calibration. This includes an electrical test. Based on the extensive evaluation, if the device is found to be unrepairable, there is no charge. We also will work to find a replacement unit. All work beyond the evaluation is sent to the customer for approval.

The final step in our calibration services process is the actual calibration. Our calibration team is considered the most experienced in the industry due to the sheer volume of work product they calibrate every day.  Interface also is heavily invested in conducting all our calibrations with the most advanced equipment, including our proprietary Gold Standard® and Platinum Standard® systems. These machines ensure that the transducers are calibrated to the most accurate ability possible before returning to the customer.

Even the most high-end manufactured load cells and finely tuned components endure accuracy degradation over continued use. To ensure your sensors are always ready for peak performance, check out our calibration services request form. We also provide a full range of calibration grade products for metrology and testing labs. You can also give us a call at 480-948-5555 to discuss your specific calibration needs.