Dear: LMR
Hello guys just to let you know I have been building a 3d printer for almost the past year. Recently I ran into a problem by blowing several A4988 motor drivers but now I can't seem to get enough power. I bought several A4988 motor drivers off of amazon for 6 dollars and they are supposed to have .8 volts from vref so they can have 2 amps to my motors but instead they are having .2 volts from vref which is not what I need. The equation for current limit on the Pololu website is current limti = vref * 2.5. This is my 3d printer or at least where I bought it. Can I have some help? Thank you.
From: Noah
Power
I am confused by your monenclature. What are you measuring? How are you measuring?
Oh sorry for the confusion let me explain.
Dear: GG
Sorry for the confusion let me explain, I am measuring the vref voltage with a multimeter. I am measuring it by connecting the positive end of the multimeter to the top of the potentiometer and the ground to ground. Is that correct? Thank you.
From: Noah
Measuring Vref
What are the conditions causing problems? Why does measuring Vref matter?
You probably will need a scope to get an accurate picture. I don’t know what the measurment will tell you but I suspect a multimeter is not the proper tool as it will report the average.
