Experimental Physics and
Industrial Control System

Dennis Nicklaus <[email protected]> · Fri, 07 Sep 2007 16:02:25 -0500

The time that epics records for updates of my PVs in some vxworks nodes

is off by one hour. This is the time seen by camonitor, the channel
archiver, etc.
If I run the vxworks time() function which gives me seconds since 1970,
the value returned

matches that returned by unix's time() (/usr/include/time.h) on my unix
nodes.
I run date() on  vxworks, I also get the correct date and time printed out.
This date() is apparently provided by EPICS since
   lkup "date"
finds it in my EPICS object .munch file.
so the system knows the proper date and time.
But somehow EPICS gets it wrong. At Geoff's suggestion, I use the epics
IOC shell function

dbtgf "PV"

to print the update time, along with other info like this

-> dbtgf "CC2_KLY:ildb0:wave9Flat"

status=0 severity=0

units=
precision=4

time=558040636 315109960

...
And the first part of the time there is supposed to be seconds since Jan
1 1990 (not 1970)

which should be 631152000 less than the time since 1970

(3600*24*(365*20+5leapdays)) = 631152000
Anyway, the time I get from dbtgf is also exactly one hour earlier
than it should be

(after I convert by adding 631152000 then comparing to unix's seconds
since 1970).

The dbtgf time matches the camonitor time, both being one hour early.

I even tried to force things a bit by adding these lines to the
beginning of my vxworks boot script:

putenv "TIMEZONE=PSTPDT::480:031102:110402"

putenv "EPICS_TS_MIN_WEST=480"

I'm really in the Central time zone, but I thought I would make it think
I was Pacific time, just

to see what happens.

And after that on vxworks,

date() does print out the time as it should be in the Pacific zone (two
hours earlier

than central), but when I do camonitor on my central time zone unix
machine, it still

tells me the PV update time is one hour too early (one hour earlier than
the actual CDT time here now).
I have run with and without the correct TIMEZONE setting, which is

putenv "TIMEZONE=CSTCDT::360:031102:110402"

but it doesn't make any difference, as well it shouldn't since we are in
the middle of CST and not

on the newly-changed-this-year shoulder dates in March or Nov.
I get this behaviour with my epics objects built with 3.14.7 and 3.14.8.2.

(I had been running 3.14.7 but decided to upgrade since I thought maybe
that was causing the problem here).

vxworks version 5.4
camonitor is 3.14.8.2 and the archiver is built against 3.14.8.2 I believe.

What do I have to do to get epics the correct time?
Thanks
Dennis
[email protected]

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System