How to Measure a Load Cell

For more data acquisition information, visit bit.ly/a2DvOw
Watch this step-by-step demonstration to see how you can measure a load cell using NI LabVIEW software and a USB data acquisition (DAQ) device.

[@beatlessteve1010]

I set up an Lm 324 to operate as an instrumentation amplifier ( using a 741 loaded down the load cell...no pun inteneded) to amplify the milli-volt output from my load cells, and also that the arduino could process the signal.

[@animeshnikam6369]

Great video. Could you please attach the product information of the load cell sensor used in this demonstration.

[@NIApps]

Have you asked this to the engineers in our LabVIEW forums? Post this question to ni dot com slash forums and link to the video - someone will be able to help you quickly. Let us know if you need more assistance. Thanks for watching!

[@AVTV14]

Please make a video about the calculation for load cell

[@dwnhll289]

We'd like to set up a very similar system: do you have a representative BOM for everything you show in the video?

[@colliemanification]

A load cell which requires 10VDC excitation with a 350 Ohm internal bridge resistance will pull about 285mW of power thus exceeding the power limit of the module. IF THIS HAPPENS, the module will override your voltage input command and reduce the excitation voltage to a level that satisfies the power limit. In this case the voltage would automatically reduce to about 7.2 VDC. If you hook up more load cells, the input voltage will continue to drop, and if your load cells have a ratiometric output (mV/V) and have been factory calibrated at 10VDC excitation, then your output will absolutely be incorrect. Therefore, you MUST use an external power supply in this scenario! Be sure that the power supply can provide the maximum amperage required for all your load cells too. And be careful not to exceed 10V from the external power supply because this will damage the module. For this reason, I would avoid a variable power supply which could accidentally go too high if you turn the wrong control knob.

[@graveyardrumblers]

Is there a way to monitor excitation and signal voltage?

[@MetalAnimeGames]

for a force sensor that has an internal amplifying circuit, the vex source has to be set as internal or external?

[@jackshepherd7950]

great video very intuitive. Please send help!

[@NIApps]

@tallman862713 For support, please call 1-866-ASK-MYNI for Applications Engineer to help or post your question to ni dot com slash forums. Both of those places will be able to help get you up and running quickly. Hope this helps!

[@tallman862713]

How do I do the calibration on LabVIEW if I have the NI SCC-68 unit and the load cell is from humanetics. I want to get results on force and moment, but when I try to follow your process step-by-step, I don't see Force and Moment on my new VI. Please!!!

[@cezarbalan6151]

In the NI9237 Data Sheet it's stated "Unless you supply external excitation voltage, NI recommends that you set the excitation voltage to a value that keeps the total power below 150 mW" In the presentation video it seems that the configuration it's exceed this power (10V excitation and 350 ohm bridge resistance = 285 mW). Is it safe to run in this condition? I'm asking this because I have to run in exactly the same situation and I need a recommendation if I should use an external excitation or not.

[@coltennabers634]

*Unless you supply external voltage..." meaning that if you are using the NI device to supply an excitation voltage then you should keep it below 150 mW. The device has an external voltage source, therefore, it isn't limited by that restriction.

[@colliemanification]

I know you posted this 3 years ago, but I am currently dealing with this exact issue. You are correct - a load cell which requires 10VDC excitation with a 350 Ohm internal bridge resistance will pull about 285mW of power thus exceeding the power limit of the module. IF THIS HAPPENS, the module will override your voltage input command and reduce the excitation voltage to a level that satisfies the power limit. In this case the voltage would automatically reduce to about 7.2 VDC. If you hook up more load cells, the input voltage will continue to drop, and if your load cells have a ratiometric output (mV/V) and have been factory calibrated at 10VDC excitation, then your output will absolutely be incorrect. Therefore, you MUST use an external power supply in this scenario! Be sure that the power supply can provide the maximum amperage required for all your load cells too. And be careful not to exceed 10V from the external power supply because this will damage the module. For this reason, I would avoid a variable power supply which could accidentally go too high if you turn the wrong control knob.

[@kumareshs7559]

Where can I purchase these load cell along with license for the LabVIEW in India?Also we intended to measure the strain developed on the fiber optic cable by applying various load what type of load cell is preferred for that application?

[@MoesKeckeEcke]

none? you have to glue strain gauges to the fibre cable sooo its only a half bridge and i think yu should contact ni.com support for more help

[@findebrosse]

what is the part number for the C series module used in this example?

[@etaks707]

USB 9237, 1:32

[@stathis420]

Since you expect the load cell to read from - 100 to 100 pounds, why didnt you calibrate the electrical values to physical units based on -100 to 100 pounds and you used 0 to .066 pounds? Thanks.

[@cyrusIIIII]

+Stathis Polydorou Is it easier for you to apply and test 100 pounds for calibration or 0.066 lbs? :)

[@JayPatel-09876]

can you tell how one can make he own load cell that can measure 10k kg...???

[@NIApps]

:)