[Dsg-rich] [Rich] rich air flow

[Valery Kubarovsky]

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>