[Dsg-rich] [Rich] rich air flow

[Brian Eng]

Unfortunately we don't currently have any way of independently monitoring the compressor status. From what I remember from initial testing the information that the web page contained was quite limited, but we should at least look again to see if it has when it is on/off. If not, maybe there is funding to get the communications module? I believe Tyler has already looked into that?

So it could just be that the compressor was on the whole time trying to build pressure vs cycling on/off. It wasn't just the pressure that wasn't cycling the flows were pretty flat too. In any event, we're all just making guesses at this point though.

I still think interlocking (and to a lesser extent the alarms) on the flows and especially the pressure when the temperatures are okay seems overly aggressive, especially with the values being so tight.

----- Original Message -----
> From: "Valery Kubarovsky" <vpk at jlab.org>
> To: "Brian Eng" <beng at jlab.org>
> Cc: "Tyler Lemon" <tlemon at jlab.org>, rich at jlab.org, "dsg-rich" <dsg-rich at jlab.org>, "Marco Mirazita"
> <Marco.Mirazita at lnf.infn.it>
> Sent: Sunday, October 14, 2018 12:17:34 PM
> Subject: Re: [Dsg-rich] [Rich]  rich air flow

> Brian,
> I think that if you switch off the compressor the pressure will drop very
> rapidly (several minutes) independently of ambient pressure. Take a look to the
> pictures. It may be a problem with pressure sensor or something connected with
> that.
> vk
> 
>> On Oct 14, 2018, at 12:05, Brian Eng <beng at jlab.org> wrote:
>> 
>> Valery,
>> 
>> It's actually the opposite, this cycling behavior is actually how it previously
>> used to look (see overview plot). The "flat" flow/pressure is a relatively new
>> phenomenon and it looks to be caused by the remnants of the hurricane coming
>> through; lower ambient pressure causes higher differential pressure in the
>> various gas volumes. Normally this shows up as the compressor cycling on/off
>> less (see pre storm plots). Since the drop was so large it manifested as not
>> even turning on.
>> 
>> The compressor used to get the tank to 120 psi, now it's only going to 110 psi,
>> which is why the bottom part of the "spike" is lower.
>> 
>> However, the flow is basically the same as it was before: this points to the
>> alarm and especially interlock values being to conservative or in many cases
>> counter-productive as they'll shut off the detector and could result in a junk
>> run prematurely.
>> 
>> Personally I would remove quite a few interlocks and loosen many of the alarms,
>> but that decision should come from the detector exports.
>> 
>> ----- Original Message -----
>>> From: "Valery Kubarovsky" <vpk at jlab.org>
>>> To: "Tyler Lemon" <tlemon at jlab.org>
>>> Cc: rich at jlab.org, "dsg-rich" <dsg-rich at jlab.org>, "Marco Mirazita"
>>> <Marco.Mirazita at lnf.infn.it>
>>> Sent: Sunday, October 14, 2018 11:02:15 AM
>>> Subject: Re: [Dsg-rich] [Rich]  rich air flow
>> 
>>> Hi Tyler,
>>> Look at zoom picture. Do you understand this behaviour?
>>> I mean this sharp drop of the pressure.
>>> Valery
>>> 
>>> 
>>> 
>>> 
>>> From: "Tyler Lemon" <tlemon at jlab.org>
>>> To: "Valery Kubarovsky" <vpk at jlab.org>
>>> Cc: "Marco Mirazita" <Marco.Mirazita at lnf.infn.it>, rich at jlab.org, "dsg-rich"
>>> <dsg-rich at jlab.org>
>>> Sent: Sunday, October 14, 2018 10:28:51 AM
>>> Subject: Re: [Rich] [Dsg-rich] rich air flow
>>> 
>>> 
>>> 
>>> Hi Valery,
>>> 
>>> I agree, the plot looks normal after 18:40 on October 13.
>>> 
>>> Attached is the same plot you shared, but with annotations showing the pressure
>>> measurement any time the value looked to be under 40 psi. The lowest it seems
>>> to have gotten was ~36 psi.
>>> 
>>> Also, the archiver doesn't ever show that the hardware interlock for the air
>>> pressure ever tripped. It's low limit is set to 35 psi.
>>> 
>>> Best regards,
>>> Tyler
>>> 
>>> 
>>> From: "Valery Kubarovsky" <vpk at jlab.org>
>>> To: "Tyler Lemon" <tlemon at jlab.org>
>>> Cc: "Mirazita Marco" <Marco.Mirazita at lnf.infn.it>, rich at jlab.org, "dsg-rich"
>>> <dsg-rich at jlab.org>
>>> Sent: Sunday, October 14, 2018 10:15:03 AM
>>> Subject: Re: [Rich] [Dsg-rich] rich air flow
>>> 
>>> Hi All,
>>> I got several calls yesterday evening and today night from CLAS12 shift about
>>> AIRPR1 alarm (currently minimum set to 35). See attached plot. I changed this
>>> limit to 30 for a moment. The plot looks not normal before Oct.13 18:40 in my
>>> view.
>>> Regards,
>>> Valery
>> <post-storm.png>
>> <pre-storm.png>
> > <overview.png>