Hi,
Thanks for the comments. I want to clarify the situation we had last
night. We heard audio warning shortly after we started data taking.
Checked the terminal, it said no compton event. Checked Compton screens,
it has non-ziro trigger rates and the histograms seemed to be updating
themselves. From all I know about Compton, which is little, I though this
was OK.
After half an hour, we are used to the warning and was not able to spot
the problem. So when it really did hung, I failed to observed it.
Chi
On Thu, 12 Jun 2003, Bill Franklin wrote:
> When I went to the counting bay a little while ago, I found that the
> Compton DAQ was hung. This happens when it is trying to broadcast events
> but can't establish a connection with the ca_server. We are still
> learning about the performance of the event transfer mode, but the surest
> recovery sequence in this case is to:
>
> 1. Kill the processes for the Compton DAQ and
> analyzer(pol-control and caRepeater on dblast09).
>
> 2. Reboot the Compton IOC.
>
> 3. Restart CODA and ET.
>
> 4. Restart pol-control for the Compton.
>
> 5. Start runs for CODA and the Compton. Make sure that Compton
> events are being received.
>
> Improved documentation for the Compton is underway and a set of updated
> instructions for operating the polarimeter will be in the counting bay by
> the end of the day.
>
> Bill
>
>
> On Thu, 12 Jun 2003, Karen Dow wrote:
>
> >
> > warnevent will tell you which type of event (physics, scaler, EPICS or
> > Compton) is missing, for each 10 second cycle.
> >
> > Bill Franklin tells me Compton ships data to ET about every 10
> > seconds. Since warnevent works on a 10 second interval, it's possible
> > that Compton information could be missing for a cycle, producing the
> > clapping. But Compton shouldn't be missing for EVERY cycle. And
> > Compton writes a message about an et failure on the blast03 screen when
> > there is truly a problem.
> >
> > Any time you restart ET you have to restart visual_scal, ca_server and
> > pol-control. Presumably this was done after run 834 when CODA was
> > restarted due to ER problems.
> >
> > I exited Compton and restarted pol-control after run 842 this morning.
> > Compton attached to ET successfully. Still do sometimes get clapping
> > from warnevent, but not every cycle. Maybe warnevent should be changed
> > to a 15 second cycle, to guarantee at least 1 Compton per cycle?
> >
> > Karen
> >
> > zhangchi wrote:
> > >
> > > We just realized that at certain point during the shift problem did really
> > > occured to compton. Because the clapping warning was on since the very
> > > beginning of the shift, while compton was OK, we failed to notice it when
> > > compton really failed.
> > >
> > > Chi, Adam
> > >
> > > On Thu, 12 Jun 2003, zhangchi wrote:
> > >
> > > >
> > > > Continued data taking with unpolarized H2, half wave plate in and out by
> > > > fills. First two runs 833, 834 were bad due to problems with
> > > > EventRecorder. restarted Coda and problem seemed go away. took data and
> > > > crunched into /net/data/4/Analysis/pro2003/before_ff as the last shift
> > > > did.
> > > >
> > > > Although Compton seems to being running, the warning system continued to
> > > > complain about no compton data. Had to turn down the volume and ignore the
> > > > warning.
> > > >
> > > > Adam, Chi
> > > >
> >
>
>
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