electrical problem adcin

[jcleaver]

trying to read a high resistance variable

var resistor is connected to ground and pic using adcin

reading with a voltmeter connected to + and pic pin is in millivolts can't seem to get the pic to display

help?

[mackrackit]

Do you have some code. A schematic or better description of the "var resistor" or do you mean potentiometer as a voltage divider would help.

[Acetronics2]

High resistance mean a closer look to the A/D section of the Pic datasheet ...

Alain

[jcleaver]

code is very simple and i am getting reading from pic so hookup is ok
think the problem is the resistance is so great might need a amp but hate to go through this two wire resistance is connected to ground and pin of pic does flucatate on voltmeter as expected again readings are in millivolts
just dont seem to get pic to respond dont know what range of resistance
or voltage

hook up is straight foward 2 wire device one wire to ground (vss ) other to pic using adcin command

[mackrackit]

Well if you think the resistance is to high, test with something else. Fixed resistor for testing?

What about the reference voltage?

[Pic_User]

Jack,


a voltmeter connected to + and pic pin is in millivolts can't seem to get the pic to display

If you put an external voltmeter between ground (Vss) and the a/d input to the PIC, what do you read?

-Adam-

[skimask]

code is very simple and i am getting reading from pic so hookup is ok
think the problem is the resistance is so great might need a amp but hate to go through this two wire resistance is connected to ground and pin of pic does flucatate on voltmeter as expected again readings are in millivolts
just dont seem to get pic to respond dont know what range of resistance
or voltage

hook up is straight foward 2 wire device one wire to ground (vss ) other to pic using adcin command

If the code is very simple, then post it.
If the schematic is equally as simple, then post it.
Maybe then, you'll learn something, and then you won't have to ask so many questions later.