1. Simultaneous supposedly doesn't work with parasitic power -- there is too great a draw on the data line. 2. There will always be a 1 second pause, but with simultaneous, only once. I.e., you write to simultaneous once, and conversion is triggered on all the temperature sensors, and after that second, all the temperature values can be read directly from the chips.
Paul On 5/25/06, Jim Duda <[EMAIL PROTECTED]> wrote:
FYI, I'm currently using owfs-2.3p6. Jim "Alfille, Paul H.,M.D." <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] Your understanding is correct. I'll check the code. I assume your sensors are separately powered, rather than parasytic. Also, a minor point, that 750msec is actually 1sec, based on large experience of the 1-wire community. Paul Alfille -----Original Message----- From: [EMAIL PROTECTED] on behalf of Jim Duda Sent: Thu 5/25/2006 1:50 PM To: [email protected] Subject: [Owfs-developers] Question on Simultaneous Can someone please help me with simultaneous? My understanding is that writing a value to the simultaneous/temperature file will cause a temperature conversion, but not incure a long delay in the write operation, as compared to reading the actual temperature. I"m trying to insure that whenever I read a temperature value, I'm always reading from the cache, to avoid a long delay on the read response. I'm running owserver without a -t parameter, so that should default to 10 seconds for which data remains in the cache. I have 4 thermometers on owfs, all of which are attached to a hub. I have a perl script which does the following: On odd seconds, it issues a write of "1" to all the simultaneous/temperature files adjacent in the hierarchy to each thermometor. I'm assuming this starts a temperature conversion for each thermometer. I believe the typical time for a temperature conversion is 750mS. On even seconds, it issues a read of each temperature device. The reading of 4 devices appears to take 6 seconds. I was expecting the reads to be much quicker, I'm assuming they should be coming from the cache. I've also changed the delay between writing and reading to 2 seconds, but I get the same behavior. Is my understanding of "simultaneous" correct? Thanks, Jim ------------------------------------------------------- All the advantages of Linux Managed Hosting--Without the Cost and Risk! Fully trained technicians. The highest number of Red Hat certifications in the hosting industry. Fanatical Support. Click to learn more http://sel.as-us.falkag.net/sel?cmd=lnk&kid=107521&bid=248729&dat=121642 _______________________________________________ Owfs-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/owfs-developers ------------------------------------------------------- All the advantages of Linux Managed Hosting--Without the Cost and Risk! Fully trained technicians. The highest number of Red Hat certifications in the hosting industry. Fanatical Support. Click to learn more http://sel.as-us.falkag.net/sel?cmd=lnk&kid=107521&bid=248729&dat=121642 _______________________________________________ Owfs-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/owfs-developers
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