Beams-doc-1479
December 1, 2004

Rob Kutschke, Computing Division


   Earlier today Jim set up data logging on 6 of the BPMS in A3,
3 H bpms and 3 V BPMS.  A copy of his email is included at 
the end of this.

   I have included 2 pictures which show a quick look at
some of the data on the proton cables:

     position.gif
     intensity.gif

In all of these pictures there are 6 traces, one each for
HA32, HA34, HA36, VA33, VA35, and VA37.  The H BPMs are on 
the bottom, with the left hand scale and the V BPMs are
on the top with the right hand scale.  

  Position is computed 26(A-B)/(A+B) and intenisty as A+B.

   Everything looks good except for one glitch for about
10 seconds near 13:49 PM.  Other than the glitch, there 
are no outliers.  This is an improvement over the 
pre-shutdown dat.  The figures

     position_detail.gif   
     intensity_detail.gif

show details of the time of the glitch.  Some of the scales
have also been fiddled a little relative to the first pair
of pictures.

   With a position of -25 mm, it is hard to believe 
that this is real beam motion.  And it does not look
like any of the noise we have seen in the past - the
glitched position is stable for about 10 seconds.
My guess is that someone wiggled a cable?

   Any other guesses?

   I also grabbed the IQ data and spot checked it:

  1) The pattern of 5 stable phases is back.
  2) The data logged position and intensities agree with 
     the data logged IQ data.
  3) The glitch is also present in the IQ data.

 ----------------------------------------------------------------------
This is a copy of Jim's email explaining what is being
data logged.

Rob,

I've started datalogging BPM values from A3.  The values 
are being logged in the TEV data logger (DUE40).  
T:HA34IQ[] and T:VA35IQ[] are being logged at 15Hz.
The following devices are being data logged at 1Hz:

T:HA32IQ[]
T:VA33IQ[]
T:HA36IQ[]
T:HA37IQ[]
T:HPA32[]
T:VPA33[]
T:HPA34[]
T:VPA35[]
T:HPA36[]
T:VPA37[]

Jim Steimel