[Halld-online] Alarm values for CDC

[Michael Staib]

Hi Hovanes,

I propose the following for low current alarm values for the CDC. Each preamp card should be drawing 0.45 A of current. On all channels there are 8 preamp cards connected with the exception of CDC:lv:Gr19 (4 cards) and CDC:lv:Gr20 (1 card). Current draw of less than 0.44 Amps per card probably is the limit we should set. 

I would propose a major alarm if the current drops below 3.52A with low voltage on for Gr1-Gr18, 1.76 for Gr19, and 0.44 for Gr20. These thresholds are rather tight, but will cover the case of a fully disconnected card as well as the case of too low a gain on the preamp.

Note that with this limit, CDC:lv:Gr20 would currently be in an alarm state. Naomi has noted previously that the gain on the one card connected to this channel looks suspiciously low. The voltage needs to be slightly increased here once the CDC is back online to bring the preamp gain in line with the other channels.

Thanks,
Mike


--
Michael Staib
Graduate Student, Dept. of Physics
Carnegie Mellon University
mstaib at cmu.edu
phone: 412-268-2983



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