[Dsg-ltcc] LTCC Gas System Controls Failure Modes Meeting

[Marc McMullen]

Hall B engineering requested a meeting with the DSG to discuss LTCC gas 
controls to be installed in the near future (weeks). The main topic of 
discussion, was to review the initial parameters for failures and 
actions needed as a result of the failures (see attachment). After 
reviewing each potential failure and deciding the appropriate way the 
gas system will need to react, the discussion moved to changes necessary 
to the way the system works.

Redundant pressure transducers on each sector will be required for 
operations and an independent safety system. The safety system would be 
comprised of the Omega process controllers, which will read an 
independent transducer and isolate the detector sector in the case of a 
HI HI or Lo Lo pressure reading.

In addition to controlling the gas flow amount and pumps (current 
controls functions), the gas controls will need to control the operation 
of the solenoids during normal Hi and Low pressure conditions, and 
during filling operations by actuating the solenoids.

In addition to the hall equipment, new transducers and solenoids will be 
installed in the gas shed to monitor tank pressures and the moisture 
content of the gas. Part of the safety system will react to isolate the 
supply from flowing gas to the hall during fault conditions.

DSG will need to modify the controls software, adding any additional 
transducer signals, change the control of the solenoids, and if 
necessary, redesign the relay chassis which actuates the solenoids.

-- 
Marc McMullen
Detector Support Group
757-269-7738

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