On 12/6/06, Paul Alfille <[EMAIL PROTECTED]> wrote: > Perhaps there are some hints here. > You are using external power (non-parasytic) and a DS18S20?
No, some of the DS18S20's are parasitic some are not. Only 2 are throwing the error. If I remember correctly one is parasitic and one isn't > The code is supposed to lock the device (use a mutex to exclude other > threads from that chip) issue a CONVERT command, wait 1sec, then read > results. If it's functioning correctly, the only reason that 2 threads > should create a problem would be the increased frequency of temperature > conversions. Perhaps there is a rest time needed? > > Can you run a type loop on a single thread reading one chip and see if you > get an error? > Tight loop? The way I was doing my test was reading 4 sensors in a tight loop and then starting another process to read the same sensors. I'll modify the script to just hammer one of the sensors that throws the error. > The other thought is that multiple simultaneous reads causes sags in the > power line that occasionally interfere with readings. In that case 2 > threads, each in a tight loop, each reading a different temperature sensor > would show an error. > > Paul Alfille -darryl -- http://randomthoughts.vandorp.ca ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Owfs-developers mailing list Owfs-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/owfs-developers