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<== Date ==> | <== Thread ==> |
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Subject: | Re: EPICS timestamp in the archiver appliance |
From: | Abdalla Ahmad via Tech-talk <tech-talk at aps.anl.gov> |
To: | "Brown, Garth" <gwbrown at slac.stanford.edu>, Mark Rivers <rivers at cars.uchicago.edu>, "Shankar, Murali" <mshankar at slac.stanford.edu> |
Cc: | "tech-talk at aps.anl.gov" <tech-talk at aps.anl.gov> |
Date: | Wed, 14 Oct 2020 07:33:11 +0000 |
Unfortunately that won't work. Most of these devices have a messed-up hardware clock, the BLM gives a timestamp in 2010, the Libera electron has a timestamp in the 1970 (Still thinking it's Unix Epoch :) ). I will try an IOC on a server which contains calc
records as a buffer to these PVs, I imagine this will eliminate the timestamp issue.
Best Regards,
Abdalla.
From: Brown, Garth <gwbrown at slac.stanford.edu>
Sent: Tuesday, October 13, 2020 9:20 PM To: Abdalla Ahmad <Abdalla.Ahmad at sesame.org.jo>; Mark Rivers <rivers at cars.uchicago.edu>; Shankar, Murali <mshankar at slac.stanford.edu> Cc: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov> Subject: Re: EPICS timestamp in the archiver appliance
If you can tolerate a small inaccuracy in the time stamps, and you have PVs on a different device with proper time stamps updating about the same rate, you could work around this by using the .TSEL field. Make the .TSEL field of PVs on the device with inaccurate
time a link to the .TIME field of a PV on the device with accurate time, and you'll get time stamps accurate to within the scan rate of the PV on the device with accurate time.
Garth
From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Shankar, Murali via Tech-talk <tech-talk at aps.anl.gov>
Sent: Tuesday, October 13, 2020 7:15 AM To: Abdalla Ahmad <Abdalla.Ahmad at sesame.org.jo>; Mark Rivers <rivers at cars.uchicago.edu> Cc: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov> Subject: Re: EPICS timestamp in the archiver appliance
>> Is there a way to configure the archiver appliance to take the local timestamp instead of the CA one?
Sorry; not at this moment. Without a proper timestamp, the archiver appliance will drop samples.
Regards,
Murali
From: Abdalla Ahmad <Abdalla.Ahmad at sesame.org.jo>
Sent: Tuesday, October 13, 2020 5:17 AM To: Mark Rivers <rivers at cars.uchicago.edu>; Shankar, Murali <mshankar at slac.stanford.edu> Cc: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov> Subject: RE: EPICS timestamp in the archiver appliance Hi Mark
No they are something else, specifically they are Libera devices from I-Tech. For example on the Libera electron I managed to get the NTP working by setting the hardware clock using “hwclock”, writing “/etc/ntp.conf” pointing to our NTP server then running the NTP daemon but the Libera BLM for example can’t set the hardware clock because it can’t find “/dev/rtc”.
We are in talks with I-Tech to solve the issue but I want to know if such configuration can be done on the archiver side. For example, “camonitor –t c” gives you the correct timestamp (local one), so I imagine EPICS somehow can be configured in such manner.
Thanks! Abdalla.
From: Mark Rivers <rivers at cars.uchicago.edu>
Are these hard-IOCs vxWorks, RTEMS, or something else? On vxWorks you should be able to make NTP work.
Mark
From: Tech-talk <tech-talk-bounces at aps.anl.gov>
On Behalf Of Abdalla Ahmad via Tech-talk
Hi
We have an issue when we want to archive PVs from a hard-IOC based device. The issue is that these devices don’t have the time set correctly and most likely somehow NTP won’t work. This causes an issue archiving these PVs because, if I understand correctly, the archiver takes the timestamp from the channel access not the local one. Is there a way to configure the archiver appliance to take the local timestamp instead of the CA one?
Best Regards, Abdalla. |