Posts

Center of Gravity Testing in Robotics Demands Precision Load Cells

/0 Comments/in , /by

As the use of robotics expands across industries and the types of robotic motions grow in complexity, advanced testing using quality measurement solutions is essential. Contact momentum and gross measurements of indicators are not enough for sophisticated robotics. With the requirements for robots and cobots to have fluid and inertial movement capabilities, control and feedback demand maximized feedback and resolution.

Related to the testing of inertia, load shifting, and interaction, is defining the center of gravity for robots’ actions and applications. The center of gravity (CoG) of a robotic system is a critical factor in its stability and performance.

The CoG is the point at which the entire weight of the system is evenly distributed. If the CoG is not properly located, the system may be unstable and prone to tipping over, which could damage the robot.

For any robotic application that deploys advanced mobility features, the center of gravity can affect the way the system moves. It can also impact the exactness of its movements. Thus, it is essential to use measurement solutions that are highly precise. See: Advancements in Robotics and Cobots Using Interface Sensors.

Why Robotic Engineers Care About CoG Testing

  • Stability: The CoG is a major factor in determining the stability of a robot. If the CoG is not properly located, the robot may be unstable and prone to tipping over. This can be a safety hazard, and it can also damage the robot. It is an expensive mistake to not have stability proven before moving forward with the design.
  • Performance: The CoG can also affect the performance of a robot. If the CoG is located too high, the robot may be less maneuverable. If the CoG is located too low, the robot may be less stable. By optimizing the CoG, robotic engineers can improve the performance of the robot and use for actions that rely on exact movement.
  • Safety: In some industries, such as manufacturing, medical and aerospace, there are safety regulations that require robots to have a certain CoG. For example, in the automotive industry, robots that are used to weld cars must have a CoG that is below a certain point. By testing the CoG of their robots, robotic engineers can ensure that they are meeting safety regulations.

There are different methods for determining the CoG of a robotic system. One common method is to use strain gage load cells. Not all load cells are designed for precision measurement. Interface specializes in precision. Center of gravity testing demands strict measurement. For example, Interface compression load cells are often used in center of gravity testing for robotics because they are very accurate and can measure remarkably small forces.

Interface load cells measure force, and they can be used to determine the weight of a system at different points. By measuring the weight of a system at different points, it is possible to calculate the location of the CoG.

Interface load cells used for center of gravity testing are typically in our miniature load cell line, due to the size of the installation and testing environment. Miniature load cells are easily embedded into robotics, as well as can be used for continuous monitoring.

Surgical Robotic Haptic Force and CoG

Robots used for surgery often utilize haptic force feedback for ensuring that the surgeon does not apply too much force, creating harm or greater impact on the patient. Haptic is the use of force, vibration, or other tactile stimuli to create the sensation of touch. In the context of invasive surgery, haptic force feedback from robotics is used to provide the surgeon with feedback about the forces they are applying to the patient’s tissue. CoG testing can help to prevent the robotic arm from tipping over during surgery.

CoG testing is important for haptic force feedback in invasive surgery because it ensures that the robotic arm is stable and does not tip over during surgery. The CoG is the point at which the entire weight of the robotic arm is evenly distributed. If the CoG is not properly located, the robotic arm may be unstable and prone to tipping over. This can be a safety hazard for the surgeon and the patient.

CoG testing is also used to optimize the design of the robotic arm for haptic force feedback. CoG testing using precision load cells can verify the performance of the robotic arm in haptic force feedback applications. After the robotic arm has been designed and optimized, CoG can ensure that the robotic arm is able to provide the surgeon with the feedback they need to perform surgery safely and accurately.

Robotic Center of Gravity on Production Line

A company is developing a new robotic arm that will be used to simulate human behavior on a manufacturing product line. The robotic arm will be used to pick and place products, and it is important that the arm is stable and does not tip over. To ensure the stability of the robotic arm, the company needs to determine the CoG of the arm. The load cell is placed on the arm, and the arm will be moved through a range of motions. The data from the load cell will be used to calculate the CoG of the arm.

CoG Testing and Multi-Axis Sensors

Multi-axis load cells are growing in use for robotics testing to provide data across 2, 3 or 6 axes at any given time. These high functioning sensors are ideal for robotic tests where there are simulations of human behaviors. This is detailed in Using Multi-Axis Sensors to Bring Robotics to Life.

To perform CoG testing using precision load cells, a robotic system can be placed on a platform that is supported by the load cells. We call these force plates. The load cells measure the weight of the system at different points, and the data is then used to calculate the location of the CoG. Visit our 6-Axis Force Plate Robotic Arm application note to learn more about force plates and multi-axis sensors.


Benefits Of Using Precision Load Cells for CoG Testing:

  • Interface precision load cells provide advanced sensors functional beyond contact and simple indicator measurement, to maximize robotic feedback and optimize performance.
  • Interface precision load cells can provide accurate measurements of the weight of a robotic system at different points.
  • Interface precision load cells are repeatable and dependable, which means that the results of CoG testing are consistent when testing robots and cobots.
  • Interface precision load cells are easy to use, which makes them a practical option for CoG testing and integration into the actual robot.

There are several benefits to using an Interface Mini Load Cells, like our ConvexBT Load Button Load Cell or MBI Overload Protected Miniature Beam Load Cell for high accuracy CoG testing.

First, the miniature load cell is small and lightweight, which makes it easy to attach to the robotic arm. Second, the load cell is designed for precision measurement, which ensures that the CoG of the arm is accurately determined. Third, the quality of Interface precision load cells provides repeatable and dependable measurement, which means that the results of CoG testing are consistent.

Using a miniature load cell of high accuracy is a valuable way to test the CoG of a robot used to simulate human behavior on a product line. This ensures that the robot is stable and does not tip over, which is critical for safety and efficiency.

In addition to testing the CoG of a robotic arm, other tests for these types of robotics include the weight of the arm, the distribution of the weight of the arm, and the friction between the arm and the surface it is moving on. By considering these factors, it is possible to accurately determine the CoG of a robotic arm and ensure that it is stable and safe to operate.

There are many factors that can affect the accuracy of CoG testing using load cells, including the design, capacity and range of measurement of the load cells, the stability of the platform, and the distribution of the weight of the system.

CoG testing is an important part of the design and development of robotic systems. By determining the CoG of a system, it is possible to improve its stability and performance. If you are interested in learning more about CoG testing using Interface precision load cells, please contact us.

ADDITIONAL RESOURCES

Types of Robots Using Interface Sensors

Robotic Grinding and Polishing

Collaborative Robots Using Interface Sensors

Advancements in Robotics and Cobots Using Interface Sensors

Using Multi-Axis Sensors to Bring Robotics to Life

Robotic Surgery Force Feedback

IoT Industrial Robotic Arm App Note

Force Measurement Solutions for Advanced Manufacturing Robotics

Reduced Gravity Simulation

Tank Weighing and Center of Gravity App Note

 

Automation-and-Robotics-Case-Study

Demystifying Specifications Webinar

/0 Comments/in /by

Interface’s technical force measurement webinar Demystifying Specifications details descriptions, terms, values and parameters found in product datasheets for load cells, torque transducers, instrumentation and specialty products. Learn from our experts what specifications need critical review, recommendations based on product categories, and the insider point of view on what is most important in terms of specifications for different use cases and tests.

Read more

I’ve Got a Load Cell – Now What? Episodes 5 and 6

/0 Comments/in /by

Reviewing the test and measurement video I’ve Got a Load Cell – Now What?, today we are highlighting Episodes 5 and 6 in the favored series.

These two installments highlight instrumentation and installation tips with best practice recommendations for the most popular load cell, the 1200 LowProfile, in addition to the 1100 LowProfile, SM S-Type and WMC Stainless Steel Miniature Load Cell products.

Once you have selected measurement device, it is equally important to review your instrumentation options. You will need a way of interpreting the output or the voltage from the load cell. This requires connecting to some type of instrumentation. If you already own an instrumentation device, you need to ensure that it is useable with any new force measurement device.

Interface offers a large line of instrumentation, from simple indicators to more complex multi-channel data acquisition systems used with multi-axis sensors, load cells and torque transducers. In addition to watching the video, be sure to check out our Instrumentation Selection Guide.

If you are selecting new instrumentation, there are a few questions to help qualify what will work best. For example, do you need a simple device to read analog outputs or advanced wireless instrumentation used with calibration-grade equipment? What type of software will you need to analyze the output data? Will you be connecting the instrumentation to a computer? As discussed in, I’ve Got a Load Cell Episode 5, here are some basic considerations for instrumentation.

Instrumentation Selection

Step 1: Electrical Wiring – Review the electrical wiring diagrams (also available on each product page). If you need to review the wiring based on engineered-to-order or custom options, contact our application engineers.

Step 2:  Signal Leads – Are you using a 4 or 6-wire configuration? A 6-wire lead provides sense. Some instrumentation options will support 6-wire signal leads. Most applications allow you to just pair with excitation.

Step 3: Cables – Identify the type of cable required with the right number of leads. For example, our standard 6-wire cable will support the sense function. We recommend shielded conductors when you order your cables.

Step 4: Grounding – Avoid ground loops in any wiring.

Step 5: Excitation Voltage – Review the sensor’s voltage of excitation on the datasheet to identify the load cell calibration. We recommend to properly match with the instrumentation’s capabilities in voltage with the load cell.

Step 6: Set-Up – Once you connect your instrumentation, you need to scale it. Review your options in the installation instructions. Some instrumentation options will take an mV entry and others will require a known load or shunt calibration. Reference your device’s calibration certificate.

In the I’ve Got a Load Cell, Now What? series Episode 6, we highlight some important diagnostics, installation tips and best practices. This video highlights examples of installation for some of our most popular load cells.

During the selection of your load cell, which usually begins with capacity and capabilities requirements, it is important to consider performance influencing factors and installation.

Use Case Considerations

  • Environmental Considerations and Exposure
  • Fatigue or Non-Fatigue
  • Overload Protection Needs
  • Off-Axis Loads
  • Dimensions
  • Mounting and Base Requirements
  • Output
  • Installation Set-Up

If you already have an older load cell, we recommend doing some back load cell health checks before putting it back into use. How can you evaluate the health of your load cell? You can do some simple diagnostics with load cells. Here are three recommended diagnostics:

  1. Zero Balance Check – If the load cell has been in use for some time, it is good to determine if there has been any potential overload or damage to the load cell. If the zero balance has shifted up or down from the nominal, that is an indication the load cell should be evaluated or repaired prior to using it in test applications.
  2. RCal or Shunt Calibration Check – Any shift from the specifications or certificate requires further evaluation.
  3. Bridge Evaluation – Some instrumentation will allow you to do a bridge evaluation. If you have any concerns on the performance or accuracy of the output, contact Interface to discuss tools that you can use to evaluate the bridge of the load cell.

The next section of Episode 6 highlights the 1200 LowProfile features, installation tips, and mounting options for assembly.

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.

Brian Peters and Elliot Speidell continue to detail the assembly and best practices for three additional products. You can watch more installation tips and recommendations related to the 1100 Model Ultra Precision Compression Only LowProfile Load Cells, SM S-Type Tension and Compression Load Cells and our popular WMC Sealed Stainless Steel Miniature Load Cell.

Interface publishes all our installation guides, diagrams and resources for support online. Go to our support resources for additional help.

Be sure to subscribe to our YouTube channel to get the latest videos on products, applications and user tips.

Interface Solutions in the World of Sports

/0 Comments/in /by

With our headquarters in the golf capitol of the U.S., it is easy to see why Interface test and measurement solutions rank top for engineers and golf manufacturers to test the force of golf balls, range equipment, clubs, and even the carts that roam the course. But our sensor technologies have a much broader reach, in both sport and geography.

Why is force measurement so heavily involved in the making and designing of sports equipment? It is obvious even by definition; sports are considered an activity involving physical exertion and skill in which an individual or team competes against another or others for entertainment.

The physical exertion often utilizes some type of apparatus, device, tool, material, equipment, or gear that requires measurement of tension, compression, or rotation. Every sport differs and type of testing also will vary, whether from initial fatigue testing or actual designing sensors into the fitness equipment like a treadmill.

Our force measurement sensors are used across a wide variety of sports equipment to evaluate performance, lifecycle, durability, and quality.

Our specialty is building high accuracy solutions for the testing and monitoring of parts and total systems that move and create force, which is vital to makers and product designers of sports equipment and machines. Our force measurement solutions are ideal for stand-alone testing rigs, production equipment, as well as to embed in sports products in order to increase operability and reliability for end users.

Interface force measurement solutions are commonplace in sports gear and equipment R&D labs, design houses, manufacturer test and production facilities. The range of products we provide is as broad as the variety of sport categories, both individual and team. This applies to products used by consumers, as well as by professional athletes, trainers, and pro sport teams. We also collaborate with several engineers and manufacturers that build exercise and training equipment.

Interface has a history of providing our low profiles, s-types and miniature load cells for testing products used in individual sports such as running, weightlifting, mountain climbing, skiing, skating, bowling, fishing and cycling. We have created solutions that measure force and torque for gear used by competitive team sports including football, soccer, hockey, rugby, tennis, baseball, water sports and more. We have even seen an extended use in tools and equipment used in auto racing and even esports, who are using our sensors to test the actual gaming devices like brake pedals, driving gear and touch screens.

Interface is a global supplier of load cells, torque transducers, multi-axis sensors, and instrumentation for sport and fitness equipment. Here a few examples of where Interface solutions were used to influence the design, test, quality, and user experience.


Fitness Equipment Testing

A premiere maker of machines used in training and gyms around the world needs multiple load measurement systems for their different fitness machines. These machines included elliptical, leg press, rowing machine, and the cable machine to start. They want to ensure the machines functioning properly to prevent injuries. It can also be used for trainers who want to conduct strength and endurance tests.  A combination of products such as the WMCFP Overload Protected Sealed Stainless Steel Miniature Load Cell, SSB Sealed Beam Load Cells, and AT103 Axial Torsion Force and Torque Transducers. Paired with Interface’s proper instrumentation, the forces can be measured, graphed, and displayed during the testing stage. Read more about these solutions here.

Golf Club Swing Accuracy

Golfers undergoing training or practice wanted a system that will monitor and record their striking accuracy and swing movement. Interface created a custom made SSB Sealed Beam Load Cell that can be attached in line with the golf handle. When a golf ball is struck, force measurements are recorded, logged, and graphed using the WTS-AM-1E Wireless Strain Bridge Transmitter. The results transmit directly to the WTS-BS-6 Wireless Telemetry Dongle Base Station when connected to the customer’s PC or laptop. Using this solution, the customer was able to successfully record, graph, and log a golf player’s striking accuracy and swing movement with Interface’s wireless force system. Read more here.

Mountain Bike Load Testing

A mountain bike manufacturing company wanted a system that measures their bike frames load capacities and vibrations on the frame. They want to ensure the bike’s high quality and frame load durability during this final step of the product testing process for their future consumers. Interface suggested installing Model SSMF Fatigue Rated S-Type Load Cell, connected to the WTS-AM-1E Wireless Strain Bridge, between the mountain bike’s seat and the bike frame. This will measure the vibrations and load forces applied onto the bike frame. The results will be captured by the WTS-AM-1E and transmitted to the customer’s PC using the WTS-BS-6 Wireless Telemetry Dongle Base Station. With this system, the mountain bike manufacturing company was able to gather highly accurate data to determine that their bikes met performance standards through this final testing. Learn more here.

 

Golf Ball Tee Testing Machine

A customer wanted to ensure their golf ball automatic tee mechanism is working for their consumers- both buying their tee’s for home use or for golfing ranges. They needed a system that will sense the presence of a golf ball, which will trigger and automatically dispense new golf ball to the tee. Interface’s WMC Sealed Stainless Steel Miniature Load Cell was installed within the golf tee, which would measure the golf balls pressure on the tee when loaded or unloaded. This load cell is electrically connected to the motor which initiates the cycle to release another ball onto the tee. Force measurements can be measured using the 9330 High Speed Data Logger when connected to the customer’s PC or laptop. With Interface’s products, the customer was provided a force solution that was able to measure the presence of a golf ball on their auto-tee machine. Get more information here.

These are just a few examples of Interface’s work in the sporting goods and fitness industry. If it moves, rotates, pushes, or pulls, chances are that Interface has a solution that can help perfect the performance. To learn more about our work in sports and consumer goods.

ADDITIONAL RESOURCES

Interface Measures Fitness Equipment with Extreme Accuracy – Case Study

Why Product Design Engineers Choose Interface

Race Car Suspension Testing

CPG Treadmill Force Measurement

CPG Gaming Simulation Brake Pedal

CPG Bike Power Pedals

CPG Bike Helmet Impact Test

Mountain Bike Shocks Testing

Fine-Tuning Testing Solutions for Championship Racing Vehicles

Fine-Tuning Testing Solutions for Championship Racing Vehicles

/0 Comments/in /by

As every championship race car team looks to find its competitive advantage, measured in seconds, Interface continues to play a pivotal role in ensuring accurate force measurement solutions are used to test the limits of every component used in motorsports.

The automotive industry has long depended on the quality and accuracy of Interface load cells, torque transducers, instrumentation, and multi-axis sensors.  Did you know it is also used in the competitive arena of auto racing?  Performance demands are constantly being pushed for all types of racing machines, whether it’s for NASCAR, IndyCar, or even the amateur level racing. What is known in the racing community is that engineers and manufacturers of equipment and parts used in these high-performance vehicles rely on Interface for precision testing solutions.

In our new case study, Building a Championship Race Car, we detail some of the specific sensor technologies used in the racing arena for high performance testing. We highlight how Interface’s TXY 2-Axis Load Cell is used in testing tires. Leading tire manufacturers, including SCCA sponsors, utilize these sensors to get precise test data on tire uniformity. The TXY has minimal cross talk across its strain gage bridges, ideal for this type of testing.

We also detail how our top load cell, the LowProfile, is frequently used in testing shocks, springs, and struts.  With any racing vehicle, control is fundamental, and the equipment used to maintain that control must be proven to meet the exceptionalism and requirements of racing professionals and their teams.

In this technical article, learn how the popular AxialTQ Torque Transducer, a bearing-less, compact wireless design, affords the test engineer suitable data collection for engine analysis, as well as brake HP calculations for active performance testing.

A competitive spirit runs deep within our Interface team, it’s what we do. We like to ensure our products are top class and help our customers win!  We also have first-hand experience in how our products are used in the racing arena. That experience affirms the positive performance effects of force measurement in auto racing.

Did you know that Interface’s Vice President of Sales, Brian Peters, has accomplished eight National Championships in Sports Car Club of America (SCCA) solo racing, and also competes in the One Lap of America cross-country, weeklong multi-competition racing event?

The annual SCCA National Championships draws more than 1,000 drivers from across North America to compete over two days. Wins are decided by mere thousandths of a second. Knowing how our products are used in high-performance racing environments, only fuels us more.

Performance and precision are critical and Interface force measurement solutions help to fine-tune critical racing vehicles, parts, and apparatus used to test different components in motorsports. We also like to say, it’s a competitive advantage. Read our case study to learn more.

Additional Resources

Powered by Interface Race Update from Brian Peters

Race Car Suspension Testing

Driving Force in Automotive Applications

Automotive and Vehicle

Force Measurement Solutions for Bolt and Screw Fastening

/0 Comments/in /by

Among the many applications of force measurement devices, one that appears to be a simple application can have a big impact on worker safety, productivity, waste reduction, assembly and product performance. In this new animated application note highlight, we take a look at the tools used for bolt fastening measurement.

Bolts and screws are used to secure different pieces or components together for nearly every product imaginable, especially when it comes to large machinery and even automobiles. The success of these products and the manufacturing of these components requires a strict level of detail that goes into the tightness of a bolt. It’s not like your typical “do it yourself” furniture where you just tighten a screw or bolt until you can’t anymore. The precision needed for certain objects to be tightened to the exact measurement is mandatory.

Interface provides measurement solutions for all types of industrial automation and toolset testing used in thousands of applications that ultimately are utilized in the building of products. In the example below, we provided devices that are used to determine the exact bolt force and tightness necessary. The goal of measuring the tightness is to avoid under or overtightening. As you can imagine, under tightening can cause components to come apart. However, over tightness can also cause significant damage to the pieces being bolted together.

Bolt Fastening Application

To show the process of measuring bolt tightness, check out this latest use case video demonstration.

For this bolt fastening application, the customer used an Interface Model LWCF Load Washer along with an Interface Model INF-USB3 Single Channel PC Interface Module to monitor force being applied during bolt tightening. The data transferred from the bolt clamping force load cell load washer with a thru-hole, to the instrumentation is displayed, logged and graphed directly onto a computer for analysis and performance testing.

This is a basic example of the test and measurement process, however, Interface also contributed to a number of real-world projects and created applications notes to provide an illustration. One of our favorites is when an industrial automation company was building an automated assembly machine for an automotive manufactur­ing plant.

The product engineers and testing team needed to tighten all of the head bolts on an engine on their assembly line to a specific torque value. Having the head bolts precisely and consistently tightened to the engine block is critical to the operation of the engine.

To measure this force, several Interface Model T33 Spindle Torque Transducers were installed in their new machine to control torque and angle and ensure the head bolt was properly tight­ened. The square drive of the T33 allowed the customer to fix their tool directly to the end of the torque sensor, streamlining the installation.

Using this solution, the head bolts were correctly installed according to manufacturer specifications, producing an engine that meets performance and reliability expectations of the auto manufacturing plant.

Here are additional solutions that showcase how Interface load cells, torque transducers, instrumentation and custom solutions are used for various tools and manufacturing processes across various industries.

Aircraft Screwdriver Fastening Control

Fastening Work Bench

Bolt Fastening Force and Torque

Interface Solutions for Robotics and Industrial Automation

Contact us to learn more how we can help you ensure the right fastening and machine control for your next projects.

 

 

 

Understanding Load Cell Temperature Compensation

/0 Comments/in /by

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, for standard use and for use in 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 cell’s performance.

If you are concerned about temperature, Interface provides specifications for every load cell we manufacture. The Interface specification datasheet, as 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.

Watch our recorded webinar Load Cell Basics, where Keith Skidmore discusses temperature compensation.  He notes during this informative presentation that if the temperature is changing during a test, it 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.

Load Cell Basics Sensor Specifications

/0 Comments/in /by

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.

 

Load Cell Basics Webinar Recap

/0 Comments/in /by

Interface applications and load cell expert Keith Skidmore was the featured presenter at the latest ForceLeaders Forum hosted event, Load Cell Basics. In his comprehensive presentation, he highlights key subjects including fundamentals of load cell design, sensor specifications, use cases, troubleshooting and valuable performance related topics.

The entire event is now available on the Interface YouTube channel.

In this 60-minute virtual event, Keith highlights commonly asked questions from both new load cell users as well as for advanced engineers and force measurement pros.

What will you learn watching the online Load Cells Basics event?

  • Load cell designs and how they work
  • Capacities, models and how to choose the right load cell
  • Factors that can impact sensor accuracy
  • Performance, moment compensation, creep, and eccentric load sensitivity
  • Calibration and troubleshooting
  • Use Cases and FAQs

The team concluded the event by answering a series of questions from the participants. They addressed advanced technical and set-up questions, as well as frequently asked inquiries about common troubleshooting issues.

Here is a sample of questions that you can find answered in the Load Cell Basics recorded event:

  • Is the temperature compensation achieved using dummy gauges?
  • Does Interface offer or have their own software to read the TEDs?
  • Can we assume that all load cells are intrinsically safe for hazardous locations?
  • What is the IP protection rating for the electrical connection?
  • What is better way to tare load cells, by electronics or mechanical preload?
  • Which is the frequency measurement limit and how fast does the load cell respond?
  • What are recommended amplifier instrumentation brands?
  • What is the most frequent problem when installing a load cell?
  • Does the cables and amplifiers affect the results of the load cell calibration?
  • For an application to 10 kN (2250 lbf), is it too much to use a 2000 lb load cell or should we use the next higher capacity?
  • What is the maximum sampling frequency for strain gage load cells?

WATCH THE EVENT AND Q&A HERE: https://youtu.be/_oHvfAzHMig

If you have additional technical questions or would like to talk about your specific application requirements, contact our Interface Application Engineers here. 

Additional resources for troubleshooting can be found here.

Our Interface Load Cell Field Guide is also helpful for troubleshooting and advanced technical support references.  You can order here.