[Dsg-rtpc] Fwd: RTPC Gas Controls Meeting Minutes

[Brian Eng]

If that is the case it won't require any hardware changes and there shouldn't be any major issues getting either done in software (on the cRIO or in EPICS).

So the only outstanding issues is #2, which as George mentioned is a change from the existing design.

> On Feb 15, 2019, at 11:29 AM, kuhn <kuhn at jlab.org> wrote:
>
> Hi again,
>
> let me also address 4) and 5) below.
>
> 4) I would think that, yes, setting the flow to zero is sufficient. After all, the gas is not flammable so no great harm is done if it takes a while to stop the flow and even it it is not 100% stopped.
>
> 5) I guess this would be less work to implement in EPICS, as the HV system will also be controlled by EPICS (I hope!). This would also allow us to more easily adjust whatever thresholds we think are appropriate for this HV shutdown (we definitely don’t want a high false alarm rate on this!)
>
> - Sebastian
>
>> On Feb 14, 2019, at 11:20 AM, Brian Eng <beng at jlab.org> wrote:
>>
>> Hi Narbe,
>>
>> Since Marc is out today I'll try and answer/comment as best as possible. I've CC'd Nathan as well.
>>
>>
>> 1) No issues with this one, data-logging of signals will be handled by Mya which is administered by ACC.
>> 2) This is new functionality as far as I'm aware. Previously pressure in the detector would be controlled via the bubbler and the flow would basically be fixed. That's not to say it can't be done, but A) is it needed? and B) how precise/fast must it be controlled?
>> 3) Again, no issues here, signals will be added to the standard Hall B alarms.
>> 4) Is setting the flow to zero sufficient for stopping the gas or will additional hardware need to be installed (i.e. a solenoid valve to positively prevent flow, if this is the case need to get DA involved).
>> 5) How should the HV interlock be handled? Is this a physical cable that needs to be added to the cRIO or is doing this via software (EPICS) acceptable?
>>
>> --
>> Brian Eng
>> Detector Support Group
>> 757-269-6018
>>
>>> On Feb 14, 2019, at 11:06 AM, Narbe Kalantarians <narbe at jlab.org> wrote:
>>>
>>> Hi Marc,
>>>
>>> Please see below for input for alarms/interlocks re: drift gas system. The ODU group will give (further) input on alarm need for the drift monitoring system.
>>>
>>> Also; if Nathan Baltzell isn’t no this mailing list, can you add him?
>>>
>>> Thank you.
>>>
>>> Narbe Kalantarians, Ph. D.
>>> Assistant Professor of Physics
>>> Virginia Union University, Dept. of Natural Sciences
>>> +1-804-257-5617 (VUU)
>>> +1-757-269-5566 (JLab)
>>>
>>>
>>>
>>>
>>>
>>>> Begin forwarded message:
>>>>
>>>> From: "Kuhn, Sebastian E." <skuhn at odu.edu>
>>>> Subject: Re: RTPC Gas Controls Meeting Minutes
>>>> Date: February 13, 2019 at 2:00:41 PM EST
>>>> To: Narbe Kalantarians <narbe at jlab.org>
>>>> Cc: "christy at jlab.org" <christy at jlab.org>, "Hattawy, Mohammad" <mhattawy at odu.edu>, Carlos Ayerbe Gayoso <gayoso at jlab.org>, "Bueltmann, Stephen L." <SBueltma at odu.edu>
>>>>
>>>> Here are my 5 cents on these questions:
>>>>
>>>> 1) Obviously we need to log all of the monitored quantities (temperatures, pressures and gas flows) in the CLAS12 data stream.
>>>>
>>>> 2) There should be a feedback loop that regulates the gas flow to keep the pressure inside the RTPC at a fixed value (set by the operator from an EPICS screen)
>>>>
>>>> 3) There should be programmable alarm levels (both hi and lo) on all pressures and the gas flow, including the supply pressure (e.g. when the bottle gets close to being empty)
>>>>
>>>> 4) Drift gas should ONLY be shut off if there is a sudden increase in gas flow indicating a rupture somewhere
>>>>
>>>> 5) In the case of 4) or if the gas flow / pressure sink BELOW an adjustable level, the HV should be shut down (not the gas flow). This is to prevent sparks if ambient air can enter due to a rupture or due to empty supply bottles
>>>>
>>>> Anything else anyone can think of? - Sebastian
>>
>>
>>
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