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Common Problems and Fixes
Masrur Hossain with BNMR group
October 6, 2005
1. Problem: Can't change magnetic field. Gives out a message like "Expected variable A1, received ?A1"
Fix:
Sometimes the bnmr magnet does not respond and you cannot change the field, this happens when the power supply of the magnet is turned off which still online in camp. This will get the magnet in a "clamped" state where it cannot be set from either camp or locally. In this case, on the camp window, you have to go into the "magnet"-> "control" -> "activity" and set it from "clamped" to "hold". Magnetic field can be changed the now in the usual way.2. Problem: Difficulty with temperature controllers getting online
Fix:
This problem happened usually with T controllers is related to the GPIB connection to camp. The symptoms is that you cannot get the T controller "online". In this case the only solution is to turn off the whole VME crate and turn it back on, then put the T controller online, via of course the "camp" window. From isdaq01, "camp -node bnmrvw" , starts a camp window.3. Problem: Suddenly the run doesn't start when clicked on "Start" from mozilla or firefox.
Fix:
It can have many reasons, like i) Legitimate D(ata)AQ(uisition) software problem, ii) There may be too many processes and the processor can't handle the multitasking that well.
Suspect the second case to begin with. Try "kill-all" and then "start-all" in sequence. Specially for the second case, giving "kill-all" at the command prompt may kill the display manager and log you out. In that case log back in and again try "kill-all" and "start-all" sequence. Even if it doesn't work, go to the browser window to connect to isdaq01 and click on "Messages". Look for clues. The red marked lines are the error messages. Make an "Elog" out of it and label it as "DAQ" and submit it. It will automatically send that Elog to DAQ people including Suzannah and others. Also, try phoning DAQ technical staff and experienced members.
4. Problem: Epics freezes while setting Na-cell voltage
Fix:It happens when you are logged in on isacepics1 as "bnqr". This may be particularly worse because it has happened that, additionally, it also freezes the display manager of the computer and you may have to kill several processes to rectify situation. Only "bnmr" has write access to Na-cell bias. Fix would be to close Epics on "bnqr" and log as "bnmr".
For more information, see here
http://daq.triumf.ca/bnmr/software/EpicsDev_on.html
5. Problem: The helicity doesn't flip
Fix:We have experienced this when connecting to bnmr@isacepics1. Looking at the "Laser Optics" page, see if the "Helicity" button is in "remote" (in this mode, helicity can be controlled by the DAQ software) mode. The page can be accessed as
ISAC_epics Main Menu-->Optics-->ILE2/Polarizer-->Laser Optics
Try making it "local" and click a few times to flip the helicities manually. One experimenter may have to go near the bnmr area to see whether it does flip when the other experimenter is clicking in the counting room. If it doesn't work, talk to the control room, contact Phil Levy, email DAQ group, in sequence.
6. Problem: The Asymmetry is zero, even when the beam is on
Fix:The first thing to look for is whether the Radio Frequency (RF) is working well.
Check
1. Whether the "scale factor" in PSM http://isdaq01.triumf.ca:8081/Alias/PSM&?exp=bnmr
has value near maximum value.
2. The DAC has been set to zero (i.e. no attenuation), in camp
AND
the RF power gives values similar to the values shown here
if the 'max_pow_1' gives values on the order of 10^(-8), the RF is certainly off.
3. Go inside the BNMR platform area and see if the attenuator has tripped. If it does, hit 'reset' on the attenuator. Go over steps #1, #2 and restart your experiment.
Page last modified: 07/23/09 02:45 by Andrew MacFarlane.