Difference between revisions of "HV HowTo for Experts"
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The HV crates sit in the hall, e.g. on the detector stacks. A set of cards with 12 channels of negative or positive HV are inserted into the crates. | The HV crates sit in the hall, e.g. on the detector stacks. A set of cards with 12 channels of negative or positive HV are inserted into the crates. | ||
Revision as of 16:10, 7 January 2014
First of all, please be aware of the simple instructions for users:
https://hallaweb.jlab.org/wiki/index.php?title=HowTo_for_Users
Overview of Architecture
The HV crates sit in the hall, e.g. on the detector stacks. A set of cards with 12 channels of negative or positive HV are inserted into the crates. A custom "serial board" (built by Javier Gomez and Jack Segal) talks to the cards. This "serial board" replaces an old, obsolete motherboard. A Perl "Shim" server (written by Brad Sawatzky) runs on a PC nearby the HV crate. The "Shim" server uses (via the Perl "Expect" module) a low-level C code written by Javier to interact with the HV crate. On the User end, a Java GUI (written by Roman Pomatsalyuk) displays the HV information and provides User control. This Java GUI talks to the Shim server. Alternatively, the Java GUI can talk to the motherboard via a Portserver. The latter alternative is being phased out, but still exists in two places at the moment: the beamline HV and one of the HV crates in the test lab DVCS setup, as I write this (Jan 2014).
All the elements in this chain must be working in order to have control and readback of HV.
Existing Crates
Here is a list of HV crates in Hall A, as of Jan 2014
Location .... PC or Portserver for Shim .... Config on ~/slowc .... How to start on adev
Left HRS (1 crate) ... Intel PC: intelha3 .... LEFT ..... cd ~adev/slowc ; ./hvs LEFT
Right HRS (top crate) ... laptop: ahut1 .... RIGHT
Right HRS (bottom crate) ... Intel PC: halladaq8 ... RIGHT ... cd ~adev/slowc ; ./hvs RIGHT (this starts both R-HRS crates)
Beamline ...... portserver hatsv4: 2003 .... BEAMLINE ..... cd ~adev/slowc ; ./hvs BEAMLINE
Where the Servers are
The Intel PCs share the following which becomes their root partition /root/diskless/i386/Centos5.8/root/shim/LecroyHV_shim and the low-level C code is in ./LecroyHV_FE
Software that runs on the Intel PCs must, however, run from their local disk because output is not permitted on the root partition.
A cron script ensures that the server is running [root@intelha3 ~]# crontab -l
- Start the shim server for HV
2,10,20,30,40,50 * * * * /shim/scripts/prepHV
On the "ahut" laptops, it's a bit different. See /home/ahut/shim/LecroyHV_shim. As above, a cron script (prepHV) runs under root.
On the DVCS computer in the test lab, you have to start everything by hand. Go to ~/slowc and see the README file.
