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

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.

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

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

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

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

Load Cell Documentation: Datasheets and Calibration Certificates

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

INTERFACE DATASHEET FUNDAMENTALS

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

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

INTERFACE CALIBRATION CERTIFICATES DETAILSIQ

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

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

Fundamentals of Load Cell Output

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

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

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

ADDITIONAL RESOURCES

Interface 1200 Precision LowProfile Load Cell Series Product Highlight

Load Cell Basics Technical Q&A Part One

Load Cell Basics Technical Q&A Part Two

Understanding Load Cell Temperature Compensation

Load Cell Basics Sensor Specifications

 

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

Interface has produced more than 100 videos, all available on our Interface YouTube channel.  We provide product videos, industry and application use cases, training, software, and set-up instructions, ForceLeaders webinars, and video discussions with our force measurement solutions experts.

One of our most popular videos is our webinar that answers the question, I’ve Got a Load Cell – Now What? In this online seminar, we discuss some of the basics about load cells, as well as offer tips for checking the health of your load cell, installation tips, usage best practices and monitoring performance.  The series concludes with an in-depth Q&A session. As with all good material, we offer a modern remake to this valuable online resource with a refreshed 7-part series that addresses important load cell topics with visual demonstrations.

In the updated series, I’ve Got a Load Cell – Now What, Interface’s Brian Peters and Elliot Speidell cover the following load cell basic topics:

  • Episode #1 Visual Inspection of Your Load Cell
  • Episode #2 How to Read the Load Cell Label
  • Episode #3 Load Cell Documentation: Datasheets and Calibration Certificates
  • Episode #4 Fundamentals of Load Cells
  • Episode #5 Load Cell Instrumentation Tips and Setup
  • Episode #6 Checking Load Cell Health and Usage Best Practices for LowProfiles, SM S-Type Load Cells and Miniature WMC Load Cells
  • Episode #7 Q&A with Brian and Elliot address incoming questions on what to do

Over the next several weeks, we’ll be highlighting some of the material that is covered in these short clips.  Today’s focus is about visual inspection and how to read a load cell label.

Visual Inspection of Your Load Cell

Visual inspection is critical for all load cells. The good news is that Interface provides quality-controlled inspection of all load cells before they leave our factory. If you are about to utilize a load cell that you have had on the shelf or has not been used for a while, visual inspection is an important first step. In this video, Brian highlights what to look for during your inspection:

  • Thread damage
  • Condition of the exterior load cell
  • Noticeable wear from exposure
  • Check for any rust
  • Inspect connectors and pins

Watch I’ve Got a Load Cell – Now What? Begin with Visual Inspection


Upon your inspection, if you would like Interface to provide a detailed inspection and calibration service before you utilize an existing sensor, contact our services team.

How to Read Interface Load Cell Labels

In this short episode, we highlight how to read an Interface load cell label. Every device we manufacturer has essential information about the sensor detailed on the label. You will find the model number, capacity, serial number and often you find options and option codes that detail the exact sensor features. Labels can also provide output data from time of calibration. To get a complete run-down on what is on Interface labels, watch I’ve Got a Load Cell – Now What? Reading Interface Sensor Labels.

Looking for more videos or resources, be sure to go to Interface’s online support resources. You will find diagrams, installation manuals, technical and troubleshooting details, educational videos and more.

ADDITIONAL RESOURCES
Interface Presents Load Cell Basics
Load Cell Basics Technical Q&A Part One
Load Cell Basics Technical Q&A Part Two
Get an Inside Look at Interface’s Famously Blue Load Cells