I was on vacation, so I didn't see the TS prestart failure, but I
very much doubt that you have to re-download the trigger in order to get
the TS to work. The connection between the trigger and the TS is in the
cables that carry the PHYSn signals to the TS inputs. If there is a
problem with the trigger, then the TS won't get event triggers, but it
should Prestart just fine.
Some other things to note:
The discriminators for the TOFs, Cerenkovs and BATS have an
inhibit applied to them. This inhibit is the NOT of (AND of "HV good" and
typing beamgate_on). The LADS discriminators have NO inhibit. If there is
an HV trip, the neutron discriminators will still put out pulses. That is
why the LADS were there, no matter what -- the only way the LADS won't
count is if the LADS HV is off.
There is an inhibit applied to the TS. It consists of the inhibit
applied to the discriminators, ANDed with "Target not in a good state" and
"spin flipper not in a good state". If HV, target or spin flipper are not
in a good state, then the TS will not process triggers.
If the TS is busy (either reading out a trigger, or between runs,
or inhibited, or hung), then the busy-inhibited scalers (there are 2, names
begin with B) will not count.
Since TOFs and CCs were all gone, I suspect either the HV had
tripped, or beamgate_on needed to be typed. This beamgate_on signal comes
from the left sector trigger CAMAC crate; if it is power-cycled, the
beamgate goes away.
Karen
At 07:51 PM 2/21/2004 -0500, Electronic Log Book wrote:
>Operators: tavi ajmasch ----
>
>
>Took Unpol H2 data, runs 4954, 4955! We have got the same TS prestart
>failed problem, but we used Tancredi's magic trick this time! After
>reseting CODA and downloaded trigger and different configurations (i.e
>physrun, flasher, etc.), then in the end when downloaded "l2trig" TS
>passed the test (prestarted) and worked!
>The main sympton was loosing TOF's, NC's and CC's plus of course PHYS's
>bits on Scalers, but the LADS were there, no matter what!
>There were some HVGui medm error messages:
>"Sat Feb 21 15:58:57 EST 2004
>medmCAExceptionHandlerCb: Channel Access Exception:
>Too many exceptions [25]
>No more will be handled
>Please fix the problem and restart MEDM
>"
>(see Elog entry# 19998).
>Also there is an update regarding Cherenkov counters for BAT's (see Elog#
>19990 for those interested). No HV should be applied to them yet. The
>attenuator, fiber light leaks should be fixed first.
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