Ok Darrel well it is all about conversion time I dont need more than a 1 degree resolution
but conversiontime is important.

Meanwhile I ordered some 18B20 versions

Still dont get why my code does not work when I simple replace my DS1820 by a DS18S20

Further , can you point me out how to read 2 sensors on 1 bus,again here
conversiontime is imporant,resolution not

Thanks

Walter