[Dsg-rich] [Rich] rich air flow

[Valery Kubarovsky]

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

>> From: "Tyler Lemon" <tlemon at jlab.org>
>> To: "Marco Mirazita" <Marco.Mirazita at lnf.infn.it>
>> Cc: rich at jlab.org, "dsg-rich" <dsg-rich at jlab.org>
>> Sent: Friday, October 12, 2018 9:25:18 AM
>> Subject: Re: [Rich] [Dsg-rich] rich air flow

>> Hello,

>> Enough time has passed since I reset the cRIO's averaging to be able to tell
>> that the averaging is not the cause of the odd airflow and pressure signals.

>> Attached are archiver plots, one from today, and one from July when averaging
>> had to be reset.

>> The one from July shows the signal returning to normal soon after resetting the
>> averaging. The signal from today does not show the same behavior.

>> It seems the most likely cause is the drop in ambient pressure.

>> Best regards,
>> Tyler

>> From: "Tyler Lemon" <tlemon at jlab.org>
>> To: "Mirazita Marco" <Marco.Mirazita at lnf.infn.it>
>> Cc: rich at jlab.org, "dsg-rich" <dsg-rich at jlab.org>
>> Sent: Friday, October 12, 2018 8:16:43 AM
>> Subject: Re: [Rich] [Dsg-rich] rich air flow

>> Hello Marco and Valery,

>> From the past behavior of the cooling system, we know that the airflows follow
>> the pressure in the cooling system's buffer tank. The attached "RICH airflows
>> and pressure 2018-10-12.JPG" shows this.

>> It also looks like the buffer tank's pressure follows the ambient pressure in
>> the hall (attached RICH pressure and Ambient pressure.JPG; NOTE units for the
>> two pressures are not the same. RICH's is in psi, the ambient is in
>> inches-water-column). This could be the cause of the ~10 slm decrease in
>> airflow.

>> Also, in the past, we have seen issues where the signal averaging in the
>> interlock LabVIEW program needs to be reset. To make sure this wasn't the cause
>> of the odd flow and pressure readings, I reset the averaging on the LabVIEW
>> User Interface at about 8:06AM. If it turns out the averaging was the cause of
>> the odd signals, we will either disable the averaging until a solution is found
>> or put in logic that will automatically reset the averaging every week or so.

>> To make sure that there isn't some other issue with the compressor, we will look
>> into a way to remotely access the status of the compressor in case we are
>> missing some sort of warning on it that would explain the behavior. This most
>> likely be setting up the compressor's web interface. Setting up the web
>> interface has not been done yet because collaborators expressed concern about
>> putting an accessible way for someone to accidentally turn the compressor off.

>> In the mean time, we will continue monitoring.

>> Best regards,
>> Tyler

>> From: "Mirazita Marco" <Marco.Mirazita at lnf.infn.it>
>> To: "dsg-rich" <dsg-rich at jlab.org>, rich at jlab.org
>> Sent: Friday, October 12, 2018 4:32:35 AM
>> Subject: [Dsg-rich] rich air flow

>> Hi all,
>> I noticed that in the last couple of days the air flow on the two lines
>> feeding the RICH went down by approximately 10%.
>> At the same time, the FPGA temperatures slightly increased.
>> Then at some time tonight the air flow started to go up again.
>> While no real problem has been encountered (tile 128 is the hottest one
>> and never went above 68 deg) it would be interesting to understand why
>> this happened.
>> See the attached strip charts.
>> Best regards,
>> Marco

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