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Interface Introduces New Torque Coupling Guide

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The new Interface Torque Coupling Selection Guide is a valuable tool for determining the correct couplings for your specific transducer and application.

This resourceful guide considers the type of torque sensor you are using, the hub type, the paired sides for connection that is best suited for your test and measurement use case.

Our couplings are durable and made to sustain performance throughout the lifetime of the matching torque transducer’s high accuracy test and measurement conditions. Learn more in our Couplings 101 post.

Interface’s Torque Coupling Selection Guide will help you narrow down your choices and find the coupling that matches your application requirements. Interface Torque Transducer shafts are compatible with either a shrink disk or collar type hub. You have the option to choose from a shrink disk, keyed, keyed large, clamping ring, or a collar hub based on your shaft’s connection requirements. We do offer keyed shaft options for our torque transducers, by request through our custom solutions group.

The types of couplings Interface offers include:

  • Single Flex Floating Mount
  • Double Flex Pedestal Mount

These are offered with the following hub configurations:

  • Shrink Disk – Keyed
  • Shrink Disk – Keyed Large
  • Shrink Disk – Shrink Disk
  • Shrink Disk – Clamping Ring
  • Collar – Collar

Torque transducers require couplings to ensure accuracy and protect your sensor investment. A torque transducer coupling is a specialized coupling that is designed to connect a torque transducer to a rotating shaft and facilitate torque measurement. This ensures that the transducer can measure the torque accurately and reliably, without any damage to the transducer or the shaft. Read more in our post: Torque Transducers and Couplings are the Perfect Pairing.

Additional factors to consider when choosing a coupling:

  • Torque transducer model: Not all couplings are equal. Interface always recommends that the couplings are designed for the specific model to eliminate any concerns with performance and reliability. Go to our torque guide to review available models.
  • Torque range: The coupling must be able to handle the maximum torque that will be applied to it.
  • Speed: The coupling must be able to operate at the desired speed without overheating or causing vibration.
  • Environment: The coupling must be able to withstand the environmental conditions in which it will be used, such as temperature, humidity, and corrosive chemicals.
  • Space constraints: The coupling must be able to fit in the available space.
  • Quality: Interface provides couplings that are made for our specific torque transducers, ensuring they are engineered to the exact specifications of the paired sensor.

When selecting an Interface torque transducer, always request or include the Interface couplings that are designed for that specific transducer model. It is especially important to review the coupling’s features and make sure they are compatible with your transducer. The coupling and transducer are designed to work together, and using the wrong coupling could lead to problems or even damage the transducer.

Without a coupling, the torque transducer cannot be mechanically connected to the rotating shaft or component. As a result, it will not be able to measure the torque being transmitted through the shaft and you lose the ability to correctly monitor and analyze torque.

We always recommend that you connect with Interface’s application engineers if you have questions. Based on experience, they can help you assess your needs and make sure you choose the right coupling accessories.

Interface provides a series of guides to help in selecting the sensor, instrumentation and supporting accessories.  You can find all the online guides here, including the most popular guides:

Learn more about in our Torque Sensor Training: Part 6 Torque Couplings

Understanding Cable Length and Temperature Effects

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Interface offers several different accessories, from interconnect cables and mating connectors to base kits and TEDS. Cables and connectors are used to attach the sensor equipment to a multitude of components and systems including data acquisition systems, power amplifiers, test stands and other instruments.

Consideration of the cable and connectivity are important when selecting any transducer. Interface has several standard cable options based on the type of measurement device, the instrumentation, the pinout, type of connector and length required for the testing use case.

Find a range of all standard cable assembly options listed here, such as:

  • Interconnect Cable from Bayonet-Type Load Cell Connector to Pigtails, 10-foot in length
  • Amplified Load Cell Bayonet-Type Connector to Pigtails
  • Screw-type Load Cell (non-TEDS) Connector to Model 9860 Indicator 10-foot in length
  • Interconnect Cable from Model TS-type Torque Transducer to Pigtails, 10-foot in length
  • Interconnect Cable from Pigtails to Pigtails, 10-foot in length
  • Interconnect Cable from TX Torque Transducer 8-pin Connector to Pigtails, 6-meters in length
  • Interconnect Cable from Model WMC/2420/2430 Bayonet-type Load Cell Connector to Pigtails, 10-foot in length

Interface uses the highest grade mating connectors to ensure that the performance of your force and torque solutions are not compromised during use. We offer options for standard connectors based on the receptacle and plug type requirements, as well as custom solutions. Our mating connectors include:

  • Bayonet-Type Mating Connectors
  • Screw-Type Mating Connectors

Cable Length and Temperature Considerations

For high accuracy force measurement, the effects of the cable on the measurement must be considered for any testing program. For constant voltage excitation there are two significant effects:

  • An effect on the sensitivity due to voltage drops over the cable length.
  • An effect on the thermal span characteristics of the load cell due to the change of cable resistance with temperature.

If the Interface load cell is purchased with a cable of any length, the sensitivity is determined with the installed cable in calibration. Always consider your cable options when buying a new sensor.

TIP: For load cells with connectors, or if a cable is added that is not designed for the exact use, there will be a loss of sensitivity of approximately 0.37% per 10 feet of 28 gage cable and 0.09% per 10 feet of 22 gage cable. This error can be eliminated if a six wire cable is run to the end of the load cell cable or connector and used in conjunction with an indicator that has sense lead capability.

Since cable resistance is a function of temperature, the cable response to temperature change affects the thermal span characteristics of the load cell cable system. For 6-wire systems this effect is eliminated and is a non-issue in performance. For 4-wire cables the effect is compensated for in the standard cable lengths offered with the load cells if the load cell and cable are at the same temperature at the same time.

There are cables designed for hot temperature or corrosive environments that can not only withstand those conditions, but also provide accurate data despite environmental challenges.

TIP: For non-standard cable lengths, there will be an effect on thermal span performance. The effect of adding 10 feet of 28 gage cable is to cause a decrease in sensitivity with temperature equal to 0.0008%/°F. For an added 10 feet of 22 gage cable the effect is to decrease sensitivity by 0.0002%/°F. In some cases, it is tolerable to degrade performance since Interface standard specification is extremely tight. However, for long cable runs or high accuracy applications, this can be a significant factor. The best approach to eliminate the problem is to run six wires to the end of the standard cable length and sense the excitation voltage at that point.

Our customers in the oil and gas industry often need force measurement solutions that can perform under extreme heat and pressure, such as in a downhole application. The cables and connectors needed for this type of project often need custom braiding and coating to ensure the wiring will not melt or corrode in this environment. Read more in Interface Pressure Compensated Downhole Load Cell White Paper.

Interface also provides our maritime and off-shore testing customers with submersible solutions in which the connection between the submersible load cell and the connector must be sealed tightly to prevent water damage to the components.

We develop all our products and accessories using only components and materials that are engineered to perform for precision testing applications. Find all the accessories here. Our engineers will also work with your directly to find the accessories that fit your specific needs. If we do not currently offer the necessary connectors and cables in house, we can work with you to create a custom solution. We also provide a variety of options depending on the data requirements, whether it is permanent monitoring, as well as different cables based on instrumentation interconnectivity.

The best option is to always purchase the cable and any mating connector at the time you choose your load cell or torque transducer. This ensures it is calibrated with the cable and performs to the exact specifications as it was designed and guaranteed by Interface.

ADDITIONAL RESOURCES

Demystifying Specifications Webinar

Force Measurement Accessories 101

Accessories

Interface Guides

TEDS 101

Basics on Load Cell Base Kits

Mating Connectors

Interface Load Cell Field Guide

Torque Transducers and Couplings are the Perfect Pairing

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Torque transducers require couplings to enhance precision and reliability in performance. The pairing ensures accurate measurements. The coupling enables the torque transducer to precisely measure torque while maintaining a secure mechanical connection to the rotating components. This facilitates data collection, analysis, and control, leading to improved performance, efficiency, and reliability when using a torque transducer in various test and measurement applications.

Couplings are designed to provide a strong and secure connection between the shafts, ensuring efficient torque transmission while minimizing stress and wear on the components. They come in distinct types and designs, each suited for specific applications and operating conditions.

For example, rigid couplings provide a solid and inflexible connection between the shafts, allowing for precise torque transmission but offering little or no flexibility to compensate for misalignments. Whereas flexible couplings are designed to accommodate small misalignments and angular offsets between the shafts. They use flexible discs to provide some degree of flexibility, dampen vibrations, and reduce stress on the connected components.

Interface Torque Transducer Models T2, T3, T4, T5, T6, T7, T8, T11 and T25 offer a range of product-specific coupling options. It is important to note that couplings are not universal, and your best options are always the couplings designed for the specific model, thus the perfect pairing. To demonstrate the range of options, here is a quick list of coupling designs:

  • Floating Mount Keyed Single Flex Couplings
  • Pedestal or Foot Mount Keyed Double Flex Couplings
  • Floating Mount Clamping Ring Single Flex Couplings
  • Pedestal or Foot Mount Clamping Ring Double Flex Couplings
  • Floating Mount Shrink Disk Single Flex Couplings
  • Pedestal or FootMount Shrink Disk Double Flex Couplings
  • Floating Mount Single Flex Couplings
  • Pedestal or Foot Mount Double Flex Couplings

A torque transducer coupling is a specific coupling designed to facilitate the connection and torque measurement between a torque transducer and a rotating shaft, providing accurate and reliable torque data. Whenever you are selecting an Interface torque transducer, be sure to request or add the Interface couplings that are designed for that specific transducer model. It is especially important to review the couplings features that pairs with your specific transducer. They are designed to work together, and you risk any problems or potential transducer failure.

Torque Transducers Require Couplings for Accuracy and to Safeguard Your Investment

Without a coupling, the torque transducer cannot be mechanically connected to the rotating shaft or component. As a result, it will not be able to measure the torque being transmitted through the shaft. This means you will lose the ability to accurately monitor and analyze torque in the system.

Using couplings is a standard requirement when using a torque transducer. They provide the mechanical connection, transmission and reduce misalignments, which all contributes to accurate and reliable torque measurements with torque transducers.

A coupling provides a means of mechanically connecting the torque transducer to the rotating shaft or component from which torque is being measured. It ensures a secure and reliable connection between the transducer and the system under test. In the absence of a coupling, the torque transducer may not be securely attached to the rotating shaft. This can lead to relative movement or slippage between the transducer and the shaft,

The coupling enables the transfer of torque from the rotating shaft to the torque transducer. As the shaft rotates, the torque is transmitted through the coupling to the transducer, which measures and converts it into an electrical signal for further analysis or control.

A coupling helps to compensate for small misalignments between the shaft and the transducer. Without a coupling, any misalignment between the two components can put additional stress on the transducer and the shaft, potentially causing premature wear, increased friction, or even catastrophic failure.

Couplings can also provide vibration damping properties by design, as they absorb or dampen vibrations and shocks that may be present in the system. This helps to protect the torque transducer from excessive mechanical stresses and safeguards torque measurements. Without a proper coupling, the transducer may also be susceptible to excessive vibrations or shocks, increasing the risk of mechanical failure.

Torque Transducer and Couplings Applications

If you are looking at a torque transducer use case, assume there are couplings that are part of the application. To point out common examples of testing programs that utilize couplings with high-performance torque transducers, the first place to start is in the automotive industry. In the automotive industry, high-performance torque transducers with couplings are used for various testing purposes. For example, during the development and testing of engines, transmissions, and drivetrain components, torque transducers coupled with the rotating shafts allow for precise measurement of torque and power output. Torque measurement data is crucial for performance analysis, efficiency optimization, and durability testing.

Torque transducers with couplings are extensively utilized in the engineering, testing, and use of industrial automation, machinery and equipment. Manufacturing processes that involve rotating components, such as pumps, compressors, and turbines, are using torque transducers coupled with the shafts to provide measurements of torque. Accuracy in data helps monitor the efficiency of the machinery, detect deviations, and ensure standard operation. All of this contributes to preventative maintenance.

There are many R&D use cases where torque transducers with couplings are required. We often see torque transducers and couplings used in material testing and structural analysis. In the renewable energy sector, wind turbines and hydroelectric generators use torque transducers and couplings.

These examples the coupling enables the torque transducer to accurately measure torque while maintaining a secure mechanical connection to the rotating components.  To explore more about couplings, be sure to tune into our recorded torque transducers webinar.


Additional Resources

Couplings 101

Torque Transducer Selection Guide

Miniature Torque Transducers 101

Choosing the Right Torque Transducer

Fuel Pump Optimization & Rotary Torque

A Comparison of Torque Measurement Systems White Paper

Rover Wheel Torque Monitoring

Torque Measurement Primer

Shunt Calibration Resistors 101

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Shunt calibration is a process of calibrating a measurement instrument using a shunt calibration resistor. The shunt calibration resistor is connected in parallel with the measurement instrument to provide a known resistance value, which is used to calculate the instrument’s accuracy.

In shunt calibration, a known current is passed through the shunt calibration (cal) resistor, which generates a known voltage drop across the resistor. This voltage drop is measured using the measurement instrument being calibrated, and the instrument’s accuracy is calculated based on the known resistance value of the shunt calibration resistor and the measured voltage drop. They create a simulation of load and verify the health of the sensor. Commonly, they are used to scale instruments.

The accuracy of the measurement instrument can be calculated by knowing the shunt resistor’s precision level and applying Ohm’s Law, which states that the current passing through a resistor is proportional to the voltage drop across it and inversely proportional to its resistance value.

Shunt calibration can be used to calibrate force measurement devices, including load cells. Interface provides shunt calibration resistors in our accessories line as “loose” resistors. They are also available with engineered to order requests for designs into cables, connectors and even within the load cell.

Shunt calibration is an important process for ensuring accurate and reliable measurements in various industrial, commercial, and scientific applications. It allows measurement instruments to be calibrated quickly and cost-effectively, and it improves the accuracy and reliability of the measurement data.

What is a shunt calibration resistor?

A shunt calibration resistor is a resistor that is connected in parallel with a measurement instrument to provide a known resistance value. The purpose of the shunt calibration resistor is to calibrate the instrument to accurately measure the current passing through it. Shunt calibration resistors are often used with load cells to improve the accuracy and reliability of their measurements.

How are shunt calibration resistors used with load cells?

Load cells typically generate a small electrical signal in response to applied force or weight. This signal is amplified and processed by a signal conditioning circuit before a data acquisition system or controller uses it. The signal conditioning circuit can utilize an internal shunt calibration resistor on the instrumentation side, or activate a resistor located upstream in the system.

Shunt calibration resistors located either in the sensor, cable, or instrument will be switched into the circuit during the shunt calibration process, shunting and diverting current in the process. This shunting effect unbalances the Wheatstone bridge, simulating loaded output from the sensor. Because the resistance value is known, sensor span output and thus instrument scaling can be accurately verified. This electrical simulated signal negates the need for physical force or torque calibration of the system.

The shunt calibration resistor provides a known resistance value, which is used to verify the health and output of the load cell, ensuring accurate system measurement of the applied force or weight. The resistor diverts a small portion of the load cell’s excitation current. The value of the shunt calibration resistor is carefully selected based on the load cell’s characteristics and the desired measurement accuracy.

Shunt calibration uses the shunt resistor to force a load cell bridge to provide a fake signal output. It allows one to check for sensor health and whether the signal behavior has deviated from an original calibration certification with initial shunt output data.

This forced signal output allows for the attached instrument to be scaled. This could be setting signal conditioner scaling:  When the load cell reaches max calibrated force, is the mV/V input properly scaled for the exact 5V, 10V or 20mA conditioner output? The other setting option is displayed units of measurement on a display: Is the load cell’s calibrated 3.999mV/V output at 100 lbs displaying 100 lbs on the display?

Shunt resistors are sized by resistance value to provide approximately two-thirds or three-quarters full scale output signal. Having this recorded value on the calibration certification the instruments can be scaled as necessary for full scale, and future shunt checks can ensure nothing is changing with the health of the circuit.

Interface Shunt Calibration Resistors – RCAL Resistors

Interface shunt calibration resistors, known as RCAL Resistors, are an accessory product. They are made from the highest components and processes to ensure the specifications for your Interface products perform to meet their published specifications. Available RCAL Models include RS-100-30K, RS-100-40K, RS-100-60K, and RS-100-120K are available.

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

  • Designed to work with Interface products.
  • Made with the highest quality components.
  • Created to maintain the specification of the product.
  • Precision wire-wound
  • 5 ppm/°C, 0.01%

U.S. dimensions and capacities are provided for conversion only. Standard product has metric capacities and dimensions. U.S. capacities available upon special request and at an additional cost.

What are the benefits of using shunt calibration resistors?

There are several benefits of using shunt calibration resistors in measurement applications:

  • Calibration: Shunt calibration resistors can be used to scale measurement instruments, ensuring that they provide accurate calibrated unit readings. Shunt calibration can often substitute the need for physical force or torque system calibration
  • Convenience: Shunt calibration can provide a quick and easy system health check either before or immediately after a test. Confirming stable and consistent shunt readings can ensure data integrity in between regular scheduled physical calibration intervals.
  • Cost-effective: Using a shunt calibration resistor is an inexpensive one time investment vs time and cost associated with pre or posttest physical calibrations. This brings the freedom for frequent and quick system calibration checks with minimal equipment down time.
  • Flexibility: Shunt calibration resistors can be used with a wide range of measurement instruments, allowing for greater flexibility in measurement applications. Additionally, many instruments allow shunt resistors to be interchangeable for support of varying sensor outputs.

Overall, shunt calibration resistors are a practical and convenient alternative to physical system calibrations. Shunt calibration resistors can be packaged into all Interface load cells with support across most of the available instrumentation as well. Frequent system health and signal stability checks are vital to ensuring consistent integrity with test data and shunt calibration resistors bring such empowerment for extraordinarily little initial investment.

Contributor: Brian Peters

Additional Resources

Metrologists and Calibration Technicians 101

System Level Calibration Validates Accuracy and Performance

Shunt Calibration for Dummies – Reference Guide

Shunt Calibration 101

Regular Calibration Service Maintains Load Cell Accuracy

Top Five Reasons Why Calibration Matters

 

 

Basics on Load Cell Base Kits

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As resilient and accurate as load cells are engineered, there is risk of damaging a load cell if they are not properly supported through mounting or mating to the test subject or test bench.

Load cell bases are designed to support and stabilize load cells. Load cell bases come in assorted sizes and configurations, depending on the intended application and the weight capacity.

Load cell bases are used with load cells that are frequently utilized in industrial equipment, test machines, and commercial testing labs. They may also be integrated into several types of equipment, such as weighbridges, conveyor systems, structural test stands, and packaging machines.

Interface publishes numerous guides on properly supporting a load cell during a test. However, for our LowProfile™ load cells, we provide complete Load Cell Base Kits to provide the engineered accuracy and necessary support for precision performance as intended in regular use. Bases minimize risks in damaging load cells from improper use.

Load cells with positive overload protection must be ordered with an Interface installed base. The positive overload option is useful when high overloads occur in applications such as: impact loads on weighing platforms; engine malfunctions during rocket or jet engine testing; transient overloads on engine dynamometers.

Interface’s Load Cell Base Kits are a type of mounting plate guaranteed to provide optimum support for the flexure. Using the base, or a support surface with its equivalent flatness and stability, is required to ensure the exceptional performance. They are heat treated and high strength bases, available in all standard sizes of our low profile models.

Standard thread size is the same as the mating load cell. Bases or flat mounting surfaces are required for all low profile load cell installations. A mounting surface that is flat to 0.0002″ T.I.R. (total indicator reading) is required, unless a base is installed.

Use of the base, or a support surface with its equivalent flatness and stability, is required to ensure the exceptional performance of the LowProfile® Series.

The threaded hole in the base is on center, and a plug is permanently installed to seal dirt and moisture out of the space between the bottom hub of the flexure and the flat surface of the base. Center hub deflects under the load until it contacts the base which provides positive overload protection. The center tapped hole is sealed to keep overload surfaces clean.

When the base and load cell are ordered together, the base and plug are factory installed using the proper hardware tightened to the required torque specs. A plug is supplied in between the cell and the base to prevent damage or errors caused by over engagement of mating parts.

There are 14 model options in standard Load Cell Base Kits in both U.S. and Metric Threads. They are available for our standard 1000, 1100 and 1200 Load Cell Series of various capacities. We offer 15 stainless steel model options to be paired with our 2400 and 3200 Load Cell Series.

Load Cell Base Kits are an excellent accessory to ensuring the most out of your LowProfile Load Cells provide the performance as designed. For complete instructions on installations, please reference our Support section on the website.

ADDITIONAL RESOURCES

Accessories

Load Cell Basics Sensor Specifications

Interface Presents Load Cell Basics

Technical Library

Force Measurement Installation Guides

Mechanical Installation Load Cell Troubleshooting 101

Off-Axis Loading 101

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Off-axis loading refers to a situation where a load cell, which is a device designed to measure force or weight, is subject to forces that are not aligned with its primary sensing axis. Load cells are typically designed to measure forces that are applied along a specific direction or axis, which is known as the primary sensing axis. When forces are applied to the load cell in other directions, this is referred to as off-axis loading.

Off-axis loading can affect the accuracy of load cell measurements, as the load cell may not be able to accurately distinguish between forces that are applied along the primary sensing axis and forces that are applied in other directions. This can result in errors in the measured weight or force.

To minimize the effects of off-axis loading, load cells are often designed with measures to reduce sensitivity to forces applied in other directions. These may include mechanical features such as strain relief structures or specialized materials that are more resistant to off-axis loading. Additionally, load cells are often installed and used in ways that minimize the likelihood of off-axis loading, such as aligning the primary sensing axis with the direction of the applied force. Be sure to carefully follow all Force Measurement Installation Guides provided with sensor.

What can be done to protect from off-axis loading?

Off-axis loading can affect the accuracy of load cell measurements, so it is important to take steps to protect against it. Here are a few ways to do so:

  • Use proper mounting and alignment: Load cells should be mounted and aligned in a way that ensures that the primary sensing axis is aligned with the direction of the applied force. This helps to minimize off-axis loading and ensure accurate measurements.
  • Use appropriate accessories: Using accessories such as adapters or mounting bases can help to ensure that load cells are properly aligned and oriented, minimizing the potential for off-axis loading.
  • Use anti-rotation features: Many load cells are equipped with anti-rotation features, such as bolt-hole patterns or keyway slots, which help to prevent the load cell from rotating around its mounting point. This can help to maintain proper alignment and reduce the effects of off-axis loading.
  • Use overload protection: Overload protection features, such as limit switches or stoppers, can be used to prevent load cells from being subjected to excessive forces or moments. This can help to prevent damage to the load cell and ensure accurate measurements.
  • Use a protective enclosure: Load cells can be placed in protective enclosures that shield them from external forces and environmental factors. These enclosures can help to protect against off-axis loading, as well as other types of interference.

By taking these steps, load cell users can help to protect against the effects of off-axis loading and ensure accurate and reliable measurements.

Product designs that mitigate off-axis loading

Engineers are constantly working to design new load cells that are more resistant to off-axis loading.  In fact, Interface product engineers have several products that are designed to protect from off-axis loading, including:

  1. ConvexBT Load Button Load Cell
  2. SuperSC S-Type Miniature Load Cell
  3. MBP Overload Protected Miniature Beam Load Cell
  4. MRTP Miniature Overload Protected Flange Style Reaction Torque Transducer
  5. MBI Overload Protected Miniature Beam Load Cell
  6. LBMP Overload Protected Compression Load Button Load Cell
  7. SMT Overload Protected S-Type Load Cell
  8. WMCP Overload Protected Stainless Steel Miniature Load Cell with Male Threads

By optimizing the mechanical design of load cells to minimize their sensitivity to off-axis loading this can include use of materials, such as composites or alloys, which are more resistant to deformation and strain. It also includes the use of specialized geometries that can help to distribute forces more evenly and reduce the effects of off-axis loading.

As well, engineers utilize built-in electronic compensation to correct for the effects of off-axis loading. This may involve using additional sensors or feedback loops to monitor the load cell’s response to external forces and adjust the output accordingly.

Interface engineers use a multi-disciplinary approach to designing load cells that are more resistant to off-axis loading. By combining advances in mechanical design, electronics, manufacturing, and simulation, they are creating load cells that are the most accurate in by classification in the world.

ADDITIONAL RESOURCES

ConvexBT – The Most Innovative Load Button Load Cell

Eccentric Loading Analysis for SuperSC S-Type Miniature Load Cell White Paper

Addressing Off-Axis Loads and Temperature Sensitive Applications

Benefits of Proof Loading Verification

How Do Load Cells Work?

Mechanical Installation Load Cell Troubleshooting 101

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The performance of a load cell force measurement system is dependent upon the reliability of the physical installation, correct interconnection of the components, proper performance of the basic components which make up the system, and calibration of the system.

Interface provides installation instructions for our products. Review the installation guide and keep on hand for installation and troubleshooting. Load cells not mounted in accordance with the manufacturer’s recommendations may not perform to the design specifications.

Always start any troubleshooting with a physical inspection of the load or weighing sensor. Resistance results from numerous factors, creating an inaccurate reading of the measurement and potential overload. If there is any appearance of dents, bending, cracks or deformation it is likely the device will need to be repaired or replaced. If none of these conditions are visible, the next step is to troubleshoot the mechanical installation.

The following is a quick checklist to reference for mechanical installation troubleshooting:

  • Check the mounting surfaces for cleanliness, flatness, and alignment
  • Check the torque of all mounting hardware
  • Check the load cell orientation
  • Check use of proper hardware as required to connect the load to the load cell
  • Check cables or output devices

Orientation is of a load cell is defined by the “dead” end on mechanical reference or load forcing source and the “live” end connected to the load to be measured by the cell. Dead end is the end closest mechanically to the cable exit or connector. A fundamental requirement is that there be one, and only one, load path.  This load path must be through the load axis of the load cell. This may sound elementary; however, it is a commonly overlooked problem.

Check all hardware and accessories when troubleshooting during mechanical installation, including all connectors, cables, thread sizes, jam nuts, swivels, mounts, and bolts. It is always important to also thoroughly inspect the cables used in a system. Evaluate the cable to ensure there is no crimping, cuts, or exposed wires. This is a common cause of mechanical installation failure.

For a quick reference, here is a discussion about what a healthy load cell should look like, and any visual clues that may potentially be a sign for an improperly working load cell.

For more helpful guides and troubleshooting tips, please visit the Interface Technical Library. Interface provides technical support for additional questions related to installation or if there is help needed in troubleshooting any of our products. Contact us here and let us know how we can help.

Additional Resources

Force Measurement Installation Guides

I’ve Got a Load Cell, Now What Play List

Force Measurement Accessories 101

 

How to Choose the Right Load Cell

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

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

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

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

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

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

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

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

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

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

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

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

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

WATCH: Load Cell Basics with Keith Skidmore

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

READ: Load Cell Field Guide

VISIT: Interface Technical Library

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

Force Measurement Accessories 101

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

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

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

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

Why Would You Need Force Measurement Accessories?

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

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

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

Interface Accessories

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

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

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

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

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

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

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

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

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

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

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

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

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