HV HowTo for Users
High Voltage Instructions -- the basics
The High Voltage is controlled by LeCroy 1458 crates and associated modules like the 1461N. A trailing "N" means negative, and a "P" means positive HV.
Simplified Instructions : To control the HV in Hall A, do the following
Login as "adev" on the "adaql1" or "adaql2" computers.
cd ~adev/slowc
To run the Left HRS alone: ./hvs LEFT
To run the Right HRS alone: ./hvs RIGHT
To run the beamline crate: ./hvs BEAMLINE
Links to more HV help
These two links provide some old but useful information.
http://hallaweb.jlab.org/equipment/daq/HVhelp.html
http://hallaweb.jlab.org/equipment/daq/gen_slow_control.html
For experts
https://hallaweb.jlab.org/wiki/index.php/HV_HowTo_for_Experts
TroubleShooting for Users
A number of things can go wrong. If these solutions don't work for you, call an expert.
1. It seems that the biggest problem at the moment is that the HV GUI loses connection and/or gives alarms. This appears to happen mostly on the R-HRS top crate. The solution is to restart the server. There are a few experts who know how to restart these -- Bob, Kalyan, and the grad. students generally know.
2. Changes to the HV GUI may seem slow or "take forever". First, give it 30 sec to respond to a change. There seems to be small probability (of order 5%) that the server doesn't respond, and the solution appears to be to toggle something on the HV GUI. E.g. change the HV by 1 volt or toggle the enable button off and then on. A small change like this "wakes up" the server.
3. Is the HV crate on ? There are two power supplies which must be turned on. Turning "on" in software will only turn on the HV if the hardware switches are in the right state and the electrical cables are plugged in.
4. If multiple cards seem "bad", I've found that power-cycling the HV crate helps. And what I mean by power-cycling is you go to the crate and manually turn it off (cutting power), then on. NOT just via the GUI but actually the hardware.
5. Need the sign ! Most of our cards are negative HV, and when you enter the target HV, you must also enter a minus sign. Like "-852" and not just "852". Beware !
