performace is not a problem, i don't know if parasite power will work for many ds18b20 ds18s20 doing convertion, maybe some ds18b20 or ds18s20 can power down try it, i don't have a network here to test
2011/2/5 patyrk <[email protected]>: > Dnia 2011-02-04, pią o godzinie 23:34 -0200, Roberto Spadim pisze: >> i never used simultaneous... >> but ds18b20 and ds18s20 sometime have a problem (maybe low power or >> problem on wire, i never founded why) >> it restart internal cpu (ds1820) >> and send 85 degree (i don't remember but it's a fixed value) >> if you get that value, you need read more two times to get the real value >> i think simultaneous read will make it more problematic... > > Just read the ds18b20 specs and found this (page 11) > http://datasheets.maxim-ic.com/en/ds/DS18B20.pdf > SKIP ROM [CCh] > The master can use this command to address all devices on the bus > simultaneously without sending out > any ROM code information. For example, the master can make all DS18B20s > on the bus perform > simultaneous temperature conversions by issuing a Skip ROM command > followed by a Convert T [44h] > command. > > So it should be possible to make conversion and the read all > scratchpads? Is should be much faster. The specs doesn't mention that > ds18b20 can't be in parasite mode. I think that just blocking the bus 1 > second will give enough time for conversion to take place. > > Now I don't see any performance increase when invoking simultaneous > before temp. read. > > -- > P4trykx > >> >> >> 2011/2/4 patyrk <[email protected]>: >> > Dnia 2011-02-05, sob o godzinie 01:10 +0000, Mick Sulley pisze: >> >> My sensors are powered, the temperature sensors are a mix of DS18B20 and >> >> DS18S20, I just used DS1820 as a generic term. >> >> >> >> Is there a way to use simultaneous conversion with pyowfs? >> > I don't know pyowfs >> > but when mounted by owfs there is a >> > >> > /mnt/owfs/simultaneous/temperature >> > >> > file and I suspect writing 1 to this file trigers the conversion signal >> > >> > >> > >> > -- >> > P4trykx >> > >> > >> > ------------------------------------------------------------------------------ >> > The modern datacenter depends on network connectivity to access resources >> > and provide services. The best practices for maximizing a physical server's >> > connectivity to a physical network are well understood - see how these >> > rules translate into the virtual world? >> > http://p.sf.net/sfu/oracle-sfdevnlfb >> > _______________________________________________ >> > Owfs-developers mailing list >> > [email protected] >> > https://lists.sourceforge.net/lists/listinfo/owfs-developers >> > >> > >> >> >> > > > > ------------------------------------------------------------------------------ > The modern datacenter depends on network connectivity to access resources > and provide services. The best practices for maximizing a physical server's > connectivity to a physical network are well understood - see how these > rules translate into the virtual world? > http://p.sf.net/sfu/oracle-sfdevnlfb > _______________________________________________ > Owfs-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/owfs-developers > -- Roberto Spadim Spadim Technology / SPAEmpresarial ------------------------------------------------------------------------------ The modern datacenter depends on network connectivity to access resources and provide services. The best practices for maximizing a physical server's connectivity to a physical network are well understood - see how these rules translate into the virtual world? http://p.sf.net/sfu/oracle-sfdevnlfb _______________________________________________ Owfs-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/owfs-developers
