stumper ? 18s20 temp

why? i have attached 2 programs for reading temp

both work and read temp and can get temp to vary

however tempworks display accurate temp the other temp is 35 deg f low any
ideas?

The 1st example is for a DS18B20 which has programmable
temperature resolutions of 0.5°C, 0.25°C, 0.125°C, or 0.0625°C.

It assumes the sensor is configured for 12 bit mode, with a resolution
of 0.0625°C per step.

The 2nd example is most likely for the DS18S20, which has 9-bit
resolution, which corresponds to 0.5°C steps.

thanks bruce

Hello all.
In regards to the posts about the DS18B20 sensors and resolution.
This seems to be a fairly common problem with these sensors.
I have trouble with this also. How can the resolution be set
in the DS18B20?

Hope this is not considered "Thread-Jacking".
Thanks in advance All.
Gordon

You can change the resolution by issuing the read scratchpad command 4Eh
followed by three bytes. TH, TL, and config. The DS18B20 data sheet explains
how it works & what values to use for config for various temp resolutions.

bruce
thanks for the responce

any chance for a sample code line

maybe showing 2 different setups

thanks

Just remember -- this still doesn't make it a DS18S20, DS1820, or any other
similar version.

bruce


thanks you are always a great resource
i am sure othersappreicate this also

jack

bruce's
program looks great but did bring up a question
how are the hser** and 2
labled on the 877a?