I am trying to write a code for my school project. Currently we have two futek load cells and a labjack T7. We are having difficulty writing the code to properly acquire data from our load cells. We have downloaded the matlab DAQ library and have looked through the various general codes it supplies but we are not sure what code we should be using where.
Could anyone get us on the right track or point us in the direction of a good resource for us to get this DAQ system set up properly.
Thank you!
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Start by going through the bridge circuit tutorial in post #13 here:
https://forums.labjack.com/index.php?showtopic=4376
Then, to read AIN0-AIN1 in matlab just use the eReadName example with name "AIN0" (assuming you did configuration in Kipling), or for an example including configuration look at SingleAINWithConfig.
Thanks for that link it helped a lot.
Now I am stuck on LJLogM, I have the white wire connected to AIN1, green to AIN0, black to GND and red to VS. I did change configuration in kipling to 0.01V for AIN0.
IN LJLog, for AIN0 the scaling equation y=a and scaled at 0.000016. AIN1 y=b scaled at 2.49. AIN2 y=c scaled at 0.08. AIN3 y=100*c/(0.01*a) scaled at 5*10^7.
Thank you again.
Where exactly are you stuck in LJLog? What is not working as expected?
The amplitude starts big. There is something wrong with the scalling.
What is the rated load of your load cell (e.g. 1000 pounds) and what is the rated output of your load cell (e.g. 2 mV/V)?
200-300 pounds and 2mV/V
Lets say your load cell has a rating of 200 pounds and 2 mV/V. That means that if your excitation is 5 volts, the load cell will output 10 mV at 200 pounds. I suggest you start by putting on a known weight and confirm you get the expected voltage.
You said your load cell is connected to AIN0 and AIN1, so you want to take a differential reading of AIN0.
Lets say you have used Kipling to configure AIN0 as differential with a range of 0.1V and then saved that as the power-up default. Then lets say you have the name "AIN0" in the first row of LJLogM (which is how it comes up by default). Look at the voltage in this first row, and confirm it reads 0.005 volts for 100 pounds.
Now start with a simple scaling equation where you assume Vexcitation is 5.0 volts. So if you use the equation y=(a/0.01)*200, and a is equal to 0.005, then the scaled value is 100.