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help can we calibrate temperature when read form DS1820

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J_expoler2

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hi
i have 2 DS1820 for measurement but when i read data form 2 ds1820 but it not same value how i can calibrate temperature as same anyone can advice me pls
best regards
 

maybe this helps:
h**p://www.elektroniikka.org/thermometer/bin/app247.pdf
 

Same problem here. I've made measuring system with ATMEL's ATMEGA8515 and 12 DS18s20 and on room temperature 8 of them show difference of less than 0.3 celsius but 4 are way off. One actually shows 4 degrees lesser temperature (instead of 23 it is 19). Have no solution for this except to throw those "faulty" sensors ( my goal is to make measuring system with 110 sensors, so i will probabbly have to obtain 200 sensors to make this work as it sould).

Setup: ATMEGA8515, normal(not parasit) power for DS1820, distance among DS approx. 3 mm. Of course, done all CRC cheking, so it is not a commuication issue, but internal hardwer of DS1820.
 

This is a standard problem with many kinds of sensors (except very expensive high precision ones).

A simple solution is to use a calbration factor for each sensor.

Set the factor to 0 at first and use something like this to get a "corrected" sensor value:

output=sensor[x] + calibration[x]

So by varying the calibration value for sensor X you will get a "correct" output even if your sensor is off.

This is just a simple offset calibration if you also need a span calibration things get more complex ...

best regards
 

J_expoler2 said:
hi
i have 2 DS1820 for measurement but when i read data form 2 ds1820 but it not same value how i can calibrate temperature as same anyone can advice me pls
best regards
Click to expand...

first you must indicate that which type of controller you going to used here is nice description and asm code for 8051 series of controller hope this will help you
 

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