[PIC] Pic multiple analog input error

Status
Not open for further replies.
S

sangeo

Member level 2
Joined
Jun 2, 2013
Messages
44
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Visit site
Activity points
1,647
Haii all ..
I have a problem with multiple analog input in pic16f877a....The problem is,when i connect second channel ,First channel shows some error
ie,My first channel is lm35 input, and second channel have an input range of 0-5v,when i connect second input Lm 35 output on lcd increased by 15/16 degree C
(around 150mv).This error not showing in proteus simulation and also i measured voltage at lm35 input pin and shows it correct value
thanks in advance
 

You might need to increase the delay between the conversion of the two channels. It would be helpful if you can show the code snippet of the ADC part.
 
Reactions: sangeo

    S

    sangeo

    Points: 2
    Helpful Answer Positive Rating
I've encountered the exact same problem.
this is due to voltage residue between the two channels.
theoratically, you should increase the delay, before and after the ADC process, also to increase the data acquisition time, and incread your TAD.

I still have this error, after modifiying the above all variables. perhaps they might work on your circuit, mine has four sensors...
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…