Battery checker

[lerameur]

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

[Archangel]

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

Hi leramuer,
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

[Dave]

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

[lerameur]

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.

[Dave]

lerameur, If your current is not exceeding more than 2.5 amps I have to ask, What gage wire are you using to supply the motor drive electronics from the battery? You could see spikes in the current if your drive electronics have crossover problems with the H switch or if you are driving a low resistance load. This is why you should have the drive electronics wired as a separate set of feeds to the battery. What type of battery and size are you using for the drive electronics and what kind and size are you using for the microprocessor electronics? I have in the past build robotic drive systems that run off of a single 12 volt battery driving the controller electronics and dual H bridge drive electronics that can supply upto 100 amps. The only thing I had to do is to place a LC network in series with the microprocessor supply to kill some of the noise as I was using the A/D convertor on board the processor with a gyro rate sensor. The battery I used was an 18 amphour 12 volt used for UPS supply's.

Dave Purola,
N8NTA

[lerameur]

hi
When i was blowing up my microcontrollers, I was using a single 12v battery at 7AH. 20Gauge wire between the battery and motor (via the h-bridge) I was actually running at 1.95Amp.
Now I added opto couplers between the microcontroller and the h-bridge. I am still working on the circuit, should be powering it up today.
k

[Dave]

lerameur, Where are the opto isolators used in the circuit?

Dave Purola,
N8NTA