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A4988 - Calibrate multimeter question


Hi there,

I have a question regarding the PolouPres_V3.pdf that explains how to calibrate the A4988. First let me just say thanks for the doc :slight_smile:

I’m confused as to where I put the multimeter. I’ve created a diagram to show what I think the pdf means. Could someone confirm that this is correct (or wrong!)?

I also have another question. I think I know what the answer will be ad I feel very stupid, but I connected the 12volt power with the polarity the wrong way around. Will that ruin the A4988?

Thanks for any help.



I just thought of another question that I think the answer is that it won’t matter, but I’d like to double check…

Referring to my diagram above, does it matter what GND the connections on the left hand side go to? i.e. doesn’t it matter whether the GNDs goto the 12volt or 5volt ground?





PololuPres_V3.pdf is not a document that we created. Could you provide a link to it? It looks like you are trying to set the current limit of your A4988. If so, your diagram looks fine, assuming your multimeter is setup correctly.

All grounds are internally connected on the board so either ground will work for your connections. However, you should keep in mind that all of the pins on the left hand side are logic pins so you should generally be thinking of the signals connected to them in terms of logic-level voltages (e.g. trying to drive them high by connecting them to 12V would destroy the board).

Lastly, connecting power backwards is very likely to permanently damage the board.



Thanks for your reply Claire.

I downloaded the pdf file from this post A4983 and A4988 Getting Started Guide

Actually I thought it was one of the Pololu staff members that had written it. I guess not!

What I’m trying to confirm, is that if I wire everything as per the diagram above and have the multimeter set to measure amps I’d be able to adjust the pot and read the difference?

Thanks again for your time.


Yes, if you wire your board as the diagram above shows, then you should be able to see a change in current when you adjust the potentiometer.



Many thanks :smiley: