Vitaliy Ziskin has provided an EPICS variable to inhibit physics
triggers to CODA while the ABS in is in unknown state. It produces a
TTL level on spigot 0 of the tan patch panel at the bottom of rack 4
(under the Trigger Supervisor crate).
I have taken this signal, put it through a LeCroy level adapter to get
a NIM level, then added it to the logic fan in/out that already does the
inhibiting for beamgate_on/beamgate_off.
The TTL signal is also T'd-off to the 17th bit of the target input
register (column 11 of visual_scal, label is TGINH).
On dblast07, you can:
caget ABS:STATUS:INHIBIT to get the status. Returns OFF (physics
triggers allowed) or ON (physics triggers inhibited)
caput ABS:STATUS:INHIBIT 0
turns inhibit ON
Physics triggers stop
TGINH reads 1
caput ABS:STATUS:INHIBIT 1
turns inhibit OFF
Physics triggers resume
TGINH reads 0
At some point when we are flipping the ABS spin automatically, this bit
will set/unset automatically. For now, I have left it set to 1 (OFF).
If for some reason you are not getting CODA events, but you do see PHY0
triggers in the scalers, this variable is one more thing to check (as
well as presence of common strobe, beamgate_on, ...).
Karen
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