For future reference:
The high voltage crates can be in a powered on state without producing HV
output. With the crate powered it will communicate, accept commands, etc.
To produce HV output four things must be satisfied:
1. crate must be powered on (physical switch on crate)
2. crate HV must be enabled (hv on command)
3. channel on which HV is desired must be enabled (ce 1 command)
4. channel on which HV is desired must have a desired voltage set
(dv xxxx command)
For the wire chamber scripts lWCHV and rWCHV (assuming the crate is powered
on) should be executed in the following sequence (x is either l or r):
1. xWCHV setup - this downloads the desired voltages, channel enable
settings, ramp rates, trip currents, etc.
2. xWCHV hv on - this enables the crate HV
3. xWCHV stby - ramp all WC channels to their standby settings
- execute this before injection
4. xWCHV oper - ramp all WC channels to their operating settings
- execute this at the start of a run after injection
5. xWCHV - display WC measured voltages
6. xWCHV st - display WC status (should be all 0001's if any
other value re-execute the stby or oper command)
7. repeat steps 5 and 6 periodically through a run
The problem this afternoon is that at some point the crate HV enable
tripped off so no HV was being generated and the command xWCHV was never
executed so it wasn't noticed that the WC's were in fact off.
Instructions for the WC HV script are in the black binder and also in the
blue WC binder.
The ROOT script WC_quick.C (root WC_quick.C) asks for a single run number
and then fills histograms of the wire hit frequency and TDC distributions.
This can be done after a run to check that the WC data looks okay (ie
signal to background is okay, no big dead areas, etc.) but since this is
generally run at the end of a run it is too late.
Anyway, hopefully this will not be a problem in the near future when the HV
GUI interface is running routinely.
--On Sunday, May 11, 2003 4:58 PM -0400 Benjamin Clasie
<clasie@lns.mit.edu> wrote:
> This was mostly a quiet shift. We took data with polarized hydrogen
> until noon (Run numbers 362 to 367). The unpolarized hydrogen runs
> 371-377 were taken without wire chamber data. While the wire chamber
> "st" command showed a normal WC status, the wc_quick script needs to be
> used at the end of each run.
>
> A.S. and B.C.
>
>
>
Cheers,
Douglas
26-415 M.I.T. Tel: +1 617 258 7199
77 Massachusetts Avenue Fax: +1 617 258 5440
Cambridge, MA 02139, USA E-mail: hasell@mit.edu
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