I was looking at the trigger supervisor today (helping Chris D'Andrea
with neutron wall cosmics), and realized there were 2 problems:
1) The cable to the INB input (inhibit) of the TS was missing. This is
what does beamgate_on, _off. It is an orange/brown twisted pair; maybe
it is the one Adrian mentions 11/8.
> We went to the D-tunnel and started troubleshooting; we went through all
> the trigger, nothing was wrong, we could trace all the signals and all
> were making sense from the BNC cables to the TDC inputs...
>
> The only significant thing we did after two hours of plugging and
> unplugging cables was to disconnect the twisted pair cable that seemed to
> come from the back of the NC retiming unit into the input of the trigger
> supervisor (the orange wire). It was not being used anyway, but nothing
> else was looking weird...
>
The INB signal comes from a Phillips level adapter (should be the 8th
ECL pin pair). The input to the LA is from an output register in CAMAC
crate 2, slot 22. When you type beamgate_on or beamgate_off (or when
hvDaemon does it for you), you are setting/unsetting a bit in that
output register. The CFDs are also inhibited by this signal; their
inhibit comes from the NIM out of the LA.
As noted above, I found the orange/brown pair disconnected from the TS;
I reconnected it. I also found it was coming from the 3rd pin pair on
the LA; moved it to the 8th. With it on the 3rd pair, you would never
have gotten any CODA triggers, since there is no input to the 3rd LA
channel. I don't know when it got moved from LA channel 8 to 3; Adrian
obviously had triggers on 11/8, he was troubleshooting low rates in some
detectors.
Verified that beamgate_on, _off now work.
2) The black/white twisted pair to inhibit 2 scalers (8th and 9th, I
believe) was connected to the TS LIV output rather than BSY. So those
scalers counted only when the TS wasn't live (run not in progress, for
example) rather than when the TS wasn't busy. Don't know when this
change was made, but I prefer using the scalers to get live fraction,
and to see no counts between runs. So I moved the cable back to the TS
BSY output.
Karen
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