how is the parasite power work? for example... it get power from data, store in a internal capacitor/inductor/batery and use it could i change bus and put a external capacitor/inductor/batery getting power from data and supply my device? (increase internal capacity) for example:
DATA ----------diode---->|----capacitor---------------> DS1820 POWER PIN GROUND --------------------------------| DATA ------------------------------> DS1820 DATA PIN GROUND ---------------------------> DS1820 GROUND PIN 2011/2/6 Pascal Baerten <[email protected]>: > hi, > > simultaneous could work in parasite power with limitations: > > 1)owfs has to issue strongpullup and lock the bus for duration of conversion > after receiving the convertT command, the unpowered sensor(s) pump the > current from the DQ line. > to give more current, the master has to put the DQ wire to vcc with a strong > pullup for the duration of the conversion > the duration is the max conversion time needed by the slowest sensor model > connected. > > 2) maximum of number of parasite powered sensors: 7 sensors. > given that > a ds18b20 use up to 1,5mA during convertT and scratchpad > a ds18b20 work down to 3V > the recommended 1wire vcc is 5V -> the acceptable voltage drop is 2V > a busmaster strongpullup has a ~180ohm to vcc > -> max current: 2v/180ohms == 11mA > max sensors "pumping" 1,5mA simultaneously on DQ= 11/1,5= 7 sensors. > > this is valid only with strongpull capables 1wire masters. > using a hub based on ds2409 will support only one parasite powered sensor > converting at a time. > > > > > Pascal > > > > 2011/2/6 Roberto Spadim <[email protected]> >> >> hummm nice =] >> try power them with 5v and check, i think it work :) >> >> 2011/2/5 patyrk <[email protected]>: >> > Dnia 2011-02-05, sob o godzinie 20:59 -0200, Roberto Spadim pisze: >> >> i don't know how alias work >> >> but you have a directory /uncached/xxxxxxxxxxxx/temperature and >> >> /xxxxxxxxxxxx/temperature >> >> you should use the cached version, not the uncached >> > >> > ok, that's right I'm using cached version, the alias could be misleading >> > so the commands look like this >> > >> > owread -s 2485 28.E4B5BF020000/temperature >> > >> > >> > But for Paul wrote, I understand that it won't work now in owfs if >> > sensors are parasite powered. >> > >> > >> > -- >> > p4trykx >> > >> > >> >> >> >> 2011/2/5 patyrk <[email protected]>: >> >> > Dnia 2011-02-05, sob o godzinie 11:23 -0500, Paul Alfille pisze: >> >> >> Yes, you need the cache to store the time markers. >> >> > >> >> > To Roberto: >> >> > Does owread -s 2485 patryk/temperature use the cache? >> >> > >> >> > >> >> >> If simultaneous works in passive mode, I'll make the change. >> >> > I think with all parasite XOR powered it will work. But I'm not >> >> > certain >> >> > what happens with mixed configuration. >> >> > Specs says this >> >> > If the DS18B20 is powered by an >> >> > external supply, the master can issue read time slots after the >> >> > Convert >> >> > T command and the DS18B20 will >> >> > respond by transmitting a 0 while the temperature conversion is in >> >> > progress and a 1 when the conversion >> >> > is done. In parasite power mode this notification technique cannot be >> >> > used since the bus is pulled high by >> >> > the strong pullup during the conversion. >> >> > >> >> > Is this "read time slots" optional? >> >> > >> >> > -- >> >> > P4trykx >> >> > >> >> > >> >> > >> >> > >> >> > >> >> > >> >> > >> >> > >> >> >> >> >> >> On Sat, Feb 5, 2011 at 10:54 AM, Roberto Spadim >> >> >> <[email protected]> wrote: >> >> >> > maybe it works with cached version, not uncached >> >> >> > >> >> >> > 2011/2/5 patyrk <[email protected]>: >> >> >> >> Hello >> >> >> >> Fist, sorry for double messages. My e-mail client went nuts. >> >> >> >> >> >> >> >> I previously said that simultaneous temp. conversion is not >> >> >> >> possible >> >> >> >> with parasite power. Well, I was wrong. This mail is to sum up >> >> >> >> all that >> >> >> >> wrote before. >> >> >> >> >> >> >> >> The specs of ds18b20 aren't very clear about it. However there is >> >> >> >> a >> >> >> >> command skip rom mentioned on page 11 >> >> >> >> >> >> >> >> 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. >> >> >> >> >> >> >> >> Moreover I asked about this simultaneous conversion on some >> >> >> >> Polish uC >> >> >> >> board and 2 users replied that they use this feature and it works >> >> >> >> even >> >> >> >> with parasite power. So I thinks it would be nice to have this >> >> >> >> feature >> >> >> >> working in owfs because its very useful with many ds1820. >> >> >> >> >> >> >> >> I've found some messages form 2006 and 2008 on this list that say >> >> >> >> simultaneous is working. But it seems not to work in my case. I >> >> >> >> use >> >> >> >> ds2480b master connected to serial port and few ds18b20 and 2 >> >> >> >> ds18s20. >> >> >> >> >> >> >> >> Maybe I'm using it wrong. This is my script >> >> >> >> #!/bin/sh >> >> >> >> owwrite -s 2485 /simultaneous/temperature "1" >> >> >> >> >> >> >> >> temp="temperature" >> >> >> >> owread -s 2485 patryk/"$temp" >> >> >> >> owread -s 2485 pokoj/"$temp" >> >> >> >> owread -s 2485 pokoj_grzejnik/"$temp" >> >> >> >> owread -s 2485 korytarz/"$temp" >> >> >> >> owread -s 2485 korytarz_grzejnik/"$temp" >> >> >> >> owread -s 2485 tata/"$temp" >> >> >> >> owread -s 2485 dziadek/"$temp" >> >> >> >> owread -s 2485 zielony/"$temp" >> >> >> >> >> >> >> >> echo "koniec" >> >> >> >> >> >> >> >> >> >> >> >> It takes about 10 seconds no matter if I use simultaneous. >> >> >> >> owwrite takie about 0.02 seconds that's to short. >> >> >> >> >> >> >> >> >> >> >> >> -- >> >> >> >> 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 >> >> >> >> >> >> >> >> >> >> >> > >> >> >> > >> >> >> > >> >> >> > -- >> >> >> > 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 >> >> >> > >> >> >> >> >> >> >> >> >> ------------------------------------------------------------------------------ >> >> >> 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 >> >> > >> >> > >> >> >> >> >> >> >> > >> > >> > >> > >> > ------------------------------------------------------------------------------ >> > 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 > > > > -- > Pascal > www.brain4home.eu > to subscribe, send a mail to <[email protected]> > > ------------------------------------------------------------------------------ > 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
