Hello!
The doc for the INA228EVM (shou241e.pdf) in section 4.2.3 says "Connect a shunt resister by doing either of the following: a. Solder a 2512 resistor across the pads of R1 that connects the IN+ and IN– inputs b. Connect an external shunt across the IN+ and IN– terminals of J1, preferably across pins 4 and 5, as shown in Figure 4-14 and Figure 4-15."
This implies that there is no existing onboard shunt resister until one is soldered across the R1 pads. But with VBUS connected to IN+, I was able to measure the current across a string of miniature solar cells across IN+ and IN- without connecting any shunt resister. So there must be something onboard already, or why is the board rated at 85V 10A?
Trying to calculate the external shunt resistance value is difficult for a solar panel output, which varies both voltage and current with solar intensity. Instead I was going to use a variable power resister thru the range of 0.01 - .5 ohms and see which gives the best voltage drop across the shunt resister.
Suggestions welcome.
Thanks, Dan
