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Interface Cable Assemblies 101

Force measurement cables and connectors are far more integral than a cable. Unlike cables for many electronics, they are not just power or data transfer sources. Instead, cables and connectors play a significant role in the total force measurement systems.

Specific cables and mating connectors are used for different applications, environments, frequency and power requirements, and paired measurement devices. This includes sensor considerations as well as instrumentation.

What are cable assemblies? 

A cable assembly for a load cell essentially acts as the lifeline between the load cell and the analog output instrumentation, transmitting the electrical signals generated by the load cell to be interpreted and measured. It’s not just a simple cable but a carefully constructed unit designed to maintain signal integrity and protect against external interference.

Interface cable assemblies are used for connecting transducers to instrumentation. Our cable assemblies are designed for easy integration with Interface measurement devices and instrumentation. Interface cables maintain the specification of the product. We provide standard cable assemblies and custom lengths, depending on your application. Shielded cables are available from Interface. Our line of cables is part of the diverse line of Interface Accessories.

Cable Assembly Basics

  • Shielding protects the signals from noise and ensures accurate readings.
  • Twisted pairs are individual conductor pairs twisted together to reduce noise interference and crosstalk between signals.
  • The material and gauge are chosen to minimize voltage drop and signal loss over the cable length.
  • Durable jackets protect the internal components from physical damage and environmental factors like moisture and abrasion.
  • Mating connectors should be compatible with the load cell and instrumentation, often sealed to prevent moisture ingress.
  • Strain relief prevents damage to the cable near the connectors from pulling or moving.
  • Proper shield grounding is crucial for effective noise mitigation.

In essence, a load cell cable assembly is engineered to ensure the fidelity and accuracy of the load cell’s signal, ultimately contributing to reliable and precise measurements in your system. Remember, the specific design and features of the cable assembly can vary depending on the type of load cell, application requirements, and environmental considerations. C

Essential Tips for Selecting a Cable

  • Length: One of the most critical considerations when selecting the suitable cable for your application is cable length. Minimize cable length to reduce signal loss and maintain accuracy. Consider the extra length needed for routing flexibility; however, it is not recommended to use extra long cables if it is not necessary.
  • Temperature range: Ensure the cable is rated for your environment’s expected operating temperature range.
  • Moisture resistance: Consider waterproof cables for outdoor or wet environments to prevent corrosion and signal degradation.
  • Flexibility: Choose a cable with appropriate flexibility for your installation. Stiffer cables are more durable but more challenging to maneuver in tight spaces.
  • Shielded or unshielded? Choose shielded cables in environments with electrical noise from motors, power lines, or radio frequencies. Unshielded cables are sufficient for cleaner environments.
  • Twisted pair or single conductor? Use twisted pairs for improved noise rejection, especially in long cable runs. Single conductors are cheaper but more susceptible to interference.
  • Number of conductors: Match the number of conductors to your load cell configuration. 4-wire for basic setups, 6-wire for advanced measurements. Consult with your application engineer to define your requirements.

TIP: For constant voltage excitation, two effects of significance can affect accuracy. 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.

Cable Length Effects

If the load cell is purchased with a cable of any length, the sensitivity is determined with the installed cable in calibration, and this is not a problem. 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 gauge cable and 0.09% per 10 feet of 22 gauge 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 with an indicator with sense lead capability.

Temperature Effects

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

Wireless Versus Cable Key Considerations

  • Type of Sensor – is there a wireless option?
  • Type of Sensor Output
  • Communication Protocol
  • Accuracy Impact 
  • Types of Errors Subject to Wireless Devices
  • Servicing Limitations with Power (Battery)
  • Line of Sight for Wireless
  • Data Rate Can Decline with Wireless Transmissions
  • Synchronization of Data

With a growing demand for wireless solutions, it is crucial to consider the results and environment before cutting the cable.

The application is vital in your cable evaluation. With a growing demand for wireless solutions, it is essential to consider the results and environment before cutting the cable. With an increasing demand for wireless solutions, it is vital to consider the results and environment before cutting the cable. Not all cables are the same. We can look at the oil and gas industry as an example of specific cable considerations. We have many oil and gas industry customers who need force measurement solutions to deal with the heat and pressure in a downhole application. The cables and connectors for this project often need custom braiding and coating to ensure the wiring won’t melt or corrode in this environment. We also have 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.

At Interface, our accessories use only the highest-quality components and materials. Our engineers will also work with you to find the accessories that fit your needs. We can work with you to create a custom solution if we don’t offer the necessary connectors and cables in-house. We also provide various options depending on the data requirements, whether permanent monitoring or portable solutions, and different cables based on data type for the type of instrument.

To learn more about our cables, visit our accessories.

ADDITIONAL RESOURCES

Understanding Cable Length and Temperature Effects

Force Measurement Accessories 101

Accessories-Brochure-2

Understanding Cable Length and Temperature Effects

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

Force Measurement Accessories 101

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

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

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

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

Why Would You Need Force Measurement Accessories?

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

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

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

Interface Accessories

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

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

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

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

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

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

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

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

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

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

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

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

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