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lerameur, Why not just read the total voltage of the series connection and then the lower cell voltage. Then subtract the lower voltage from the total voltage to get the upper cell voltage? That way you only have 1 ground connection.
Dave Purola,
N8NTA
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the batteries are not in series. One 12v battery for the controller, and a 24v (well 2 12v battery in series) for the motors. That is if I understood you correctly
k
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lerameur, After my reply I re-read the post and understood the grounds are not common. Is this true? Why can't you common the grounds?
Dave Purola,
N8NTA
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I want to isolate the circuit . There was too much harmonics on the ground, it was killing the microcontroller.
what about an opto coupler ?
I am also looking some amplifier , any thoughts on this one: ISO124
Last edited by lerameur; - 30th January 2007 at 22:42.
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Ground Loops
Hi leramuer,Originally Posted by lerameur
about 35 years ago I worked for a company that made audio gear for radio stations and such. I remember, talking to the engineers about ground loops and they advised using 1 common tie point for all grounds, period. You might try that for the problem you mentioned.
JS
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lerameur, Joe S. is right.... I have been designing test systems for about 30 years and have repaired problems with systems that stemed from having multiple grounds. If I was to design the type of system you are talking about I would have 1 single ground point. The noise you are talking about (upsetting the processor) is more than likley caused by the current being drawn from the 24 volt return from the motor drive system and where you are sensing or referencing the ground. I can't beleive that the processor 12 volt supply is that noisy or is drawing that much current. If both battery system returns were tied together at the batterys this should eliminate most of your problems. How much current is the 24 volt motor supply battery required to deliver?
Dave Purola,
N8NTA
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so basically tieing the two grounds together? then why not use a single battery for everything, wouldn't that be the same?
I am using about 2.5A for the motor battery.
you are saying that the harmonic going back to the battery will not affect the microcontroller ?
I suppose the harmonics is g0ing back on the ground, therefore affecting all the grounds in the system ?
I dont have 35 years experience like you guys, just trying trying to learn.
Last edited by lerameur; - 31st January 2007 at 13:39.
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