Janos, Dave:
VACSTAT version 1.10
Following several recent false positive VACSTAT alarms due to noise in a single gauge (usually BSC3 PT132) we have made a change to the code to mitigate this.
The new alarm logic is:
- If a single gauge trips, increase the sensitivity of the other gauges. Then if at a later time a second or more gauges trip, send the cell phone alarm to the vacuum team.
- If multiple gauges trip at the same time, send the cell phone alarms to the vacuum team.
The alarm system was modified to alert the vacuum team if the channel H1:CDS-VAC_STAT_GLITCH_NUM_GAUGES is 2 or greater.
My cell phone alarm will continue to sound on a single gauge trip, because tripped gauges are latched out from the sytem and we need to reset any false positives to restore the nominal functionality.
The new code was installed Friday afternoon (15:40 01nov2024 PDT).
Design reasoning:
In the event of an in-chamber gas release the local gauge will see a large signal. Gas migration to neighboring chambers will result in smaller signals there. Increasing their trip sensitivities will increase the chance of seeing a multi-chamber event.
A new enumerated PV has been added, H1:CDS-VAC_STAT_STATE.
It can have the following values
VACSTAT_STATES = {
"MONITORING": 0,
"SINGLE": 1,
"MULTIPLE": 2,
}
MONITORING = nominal state.
SINGLE = one chamber has tripped, all the others have been set to their "sensitive" trip settings.
MULTIPLE = number of chambers tripped >= 2, alarms have been sent.