I've built a data logger for measuring performance of an electric go cart. All seems to be working well and i'm trying to calibrate my current sensor. When I read the output voltage of the transducer it reads exactly what my Arduino UNO reads. But when I convert that voltage to current using the info on the data sheet, the results are around .4 amps different from a clamp on amp meter. Measured amps is 27.4 and the amp meter says 27. I'm averaging around 100,000 samples. I tend to put more faith in a "store bought" meter, but I'm not sure what to believe.
I can easily modify my code to get exact resutls but that will require me knowing what unit is right. . The relationship is linear so a simple y = mx + b is how i'm calcualting the current.
Here's a link to my curren transducer https://www.amazon.com/Uni-T-B4Q094-UT210E-Current-Capacitance/dp/B00O1Q2HOQ/ref=sr_1_15?ie=UTF8&qid=1511054990&sr=8-15&keywords=clamp+on+amp+meter
Here's the link to my current meter
Thoughts on how to calibrate current sensors?
Thanks in advance.