Experimental Physics and
Industrial Control System

"Kalantari Babak" <[email protected]> · Fri, 14 Aug 2009 12:31:55 +0200

Hi Andrew,

I have a question regarding the vxWorks time driver of generalTime
(drvDevVWTime.c) which we use in EPICS 3.14.8 and mv2304/mv5500.

The VWTime is the lowest priority time source and is synced with a
higher priority time source (e.g. NTPTime) if a valid one exists.
However if there is no higher valid time source available, the VWTime is
also not valid if clock_gettime() says a time smaller than
VXWORKS_TO_EPICS_EPOCH which is normally the case after a reboot.

The result is that there is no EPICS timestamp available at all (it is
<undefined>) and if any record gets processed it prints "<Record_name>
recGblGetTimeStamp failed" on the IOC shell.

Shouldn't the VWTime (for systems with vxWorks OS) be always available
even if it is not synced? (It could at least be set to EPICS epoch.)
Is it also like this in 3.14.10 after changes in generalTime?

The other issue is RTC: 
It seems that vxWorks clockLib (clock_gettime, clock_settime, ...) does
not make use of on-board RTC. If I call clock_gettime() after a soft
reboot it always starts from 0 while the RTC should run at least as long
as there is power. Wouldn't it be better to use RTC to maintain time
sources like VWTime?      

Regards,
Babak

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System