Hi Kiste, So I understand you'd use several ADC inputs per DC motors, each plugged to a voltage divider. The one being in a proper interval values would be the one to use. That would be a discreet normalization, but that's a start !
Thanks Seb 2010/10/22 Oliver Seitz <[email protected]> > > >That is, if I'm using 24V DC motors, voltage coming to ADC will be too > great and could damage the PIC (or worse, I could get wrong data). > > Neither is necessarily true. PIC inputs have diodes, so if you have a > resistor large enough to limit the current to about 20mA, no damage should > be done. You can, if you want, add external diodes, schottky then, to be > sure. One diode with its cathode to Vcc, one with its anode to GND. > > First I thought to use a resistor ladder and use a low (1.0V or so) Vref, > but Vref should be 2.5V or higher to be sure... > > So, let's take just a bunch of dividers... > > The most sensitive input will just get a 10kOhm series resistor to limit > the current. The 12V input gets 15kOhm:10kOhm, the 24V input gets > 38kOhm:10kOhm. > > All divider inputs are connected together to the motor. All dividers base > is GND. Each divider middle is connected to its own analog input. > > Theoretical there should be no damage as long as the voltage at the input > stays below (10kOhm*0.02A=) 200V, but don't test that with your most > valuable PIC... > > Now, read the most sensitive input. If it reads 1020 or more, it is out of > range. Take the next one then. If reading is below 500 or so, you can switch > back to the more sensitive input. > > Greets, > Kiste > > > -- > You received this message because you are subscribed to the Google Groups > "jallib" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]<jallib%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/jallib?hl=en. > > -- Sébastien Lelong http://www.sirloon.net http://sirbot.org -- You received this message because you are subscribed to the Google Groups "jallib" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/jallib?hl=en.
