<html><body><div style="font-family: times new roman,new york,times,serif; font-size: 12pt; color: #000000"><div data-marker="__QUOTED_TEXT__"><div style="font-family: times new roman,new york,times,serif; font-size: 12pt; color: #000000"><div>Hello,<br></div><br><div>From the compressor manual, the web interface Brian mentioned seems to give us the same information as if we were standing right in front of the compressor. There is a communication module that we could buy that would give us Modbus communication to the compressor. I will contact Atlas Copco to get a quote on the module and to see what other features and capabilities the communication module would give us.<br></div><br><div>In regards to Sandro's email, what he said is correct. The behavior of the pressure and airflows from October 11 to October 13 is what you see if you don't allow the buffer tank to build up pressure when starting the system. It could be that the ambient pressure change was great enough to force the buffer tank pressure below a value that allows steady operation. However, like Brian said, that is just a guess.<br></div><br><div>I do know we are running the compressor at it maximum capabilities. It's output pressure regulation is set to regulate between 104 psi and 113 psi. 113 psi is the maximum output pressure the compressor is capable of. A 9 psi differential is the the minimum recommended differential between high and low. Adjusting the airflow to a lower value that still maintains low enough temperatures may help the system run more stably. We would have to take the time to methodically lower the airflow and study the resulting temperature increase, though.<br></div><div><br data-mce-bogus="1"></div><div>Best regards,<br data-mce-bogus="1"></div><div>Tyler<br data-mce-bogus="1"></div><br><br><hr id="zwchr"><div><b>From: </b>"Tomassini Sandro" <sandro.tomassini@lnf.infn.it><br><b>To: </b>"Brian Eng" <beng@jlab.org><br><b>Cc: </b>"dsg-rich" <dsg-rich@jlab.org>, "Mirazita Marco" <marco.mirazita@lnf.infn.it><br><b>Sent: </b>Sunday, October 14, 2018 3:19:12 PM<br><b>Subject: </b>Re: [Dsg-rich] [Rich] rich air flow<br></div><br><div><div dir="auto">Hi all, <br></div>
<div dir="auto">I remember the same behavior when we started the system the first time. In other words I try to explain: if the air flow rate is set to the nominal value (the gate valve is open) and the air tank is empty, when the compressor is switched on then the pressure vs time in the tank assumes exactly the same behavior you have posted so far and this behavior remains stable in time. <br></div>
<div dir="auto">If the air flow rate to the rich is set to zero (gate valve is off), when the compressor is switched on and you wait until the pressure in the tank reaches the max value before opening the flow to the rich than the pressure behavior vs time is stable. <br></div>
<div dir="auto">Why this behavior? I think there is an instability in the system that shows up when the tank pressure drops below a certain value. Someone should study the stability of the system (poles and zeros) to find out the limit parameters! I know it is not so easy! <br></div>
<div dir="auto">Hope it is clear. <br></div>
<div dir="auto">Sandro<br><br></div>
<div dir="auto">Inviato da <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__www.bluemail.me_r-3Fb-3D13688&d=DwMFaQ&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=9YtCiIg5kE6YCo5iFAyFiMgzNCONVcBowotEOgGZ4Co&m=WIbsgy_U5kgg05pqp35kS3FxHtlKwAHBfZZe7pPiXvM&s=tykDjcQ_55969neY0466q2q8JG4HPh2rOYjM1WHsH_g&e=" target="_blank">BlueMail</a> </div>
<div class="gmail_quote">Il giorno 14 ott 2018, alle ore 19:16, Brian Eng <<a href="mailto:beng@jlab.org" target="_blank">beng@jlab.org</a>> ha scritto:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<pre class="blue">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?<br><br>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.<br><br>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.<br><br>----- Original Message -----<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;"> From: "Valery Kubarovsky" <vpk@jlab.org><br> To: "Brian Eng" <beng@jlab.org><br> Cc: "Tyler Lemon" <tlemon@jlab.org>, rich@jlab.org, "dsg-rich" <dsg-rich@jlab.org>, "Marco Mirazita"<br> <Marco.Mirazita@lnf.infn.it><br> Sent: Sunday, October 14, 2018 12:17:34 PM<br> Subject: Re: [Dsg-rich] [Rich] rich air flow<br></blockquote><br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;"> Brian,<br> I think that if you switch off the compressor the pressure will drop very<br> rapidly (several minutes) independently of ambient pressure. Take a look to the<br> pictures. It may be a problem with pressure sensor or something connected with<br> that.<br> vk<br> <br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #ad7fa8; padding-left: 1ex;"> On Oct 14, 2018, at 12:05, Brian Eng <beng@jlab.org> wrote:<br> <br> Valery,<br> <br> It's actually the opposite, this cycling behavior is actually how it previously<br> used to look (see overview plot). The "flat" flow/pressure is a relatively new<br> phenomenon and it looks to be caused by the remnants of the hurricane coming<br> through; lower ambient pressure causes higher differential pressure in the<br> various gas volumes. Normally this shows up as the compressor cycling on/off<br> less (see pre storm plots). Since the drop was so large it manifested as not<br> even turning on.<br> <br> The compressor used to get the tank to 120 psi, now it's only going to 110 psi,<br> which is why the bottom part of the "spike" is lower.<br> <br> However, the flow is basically the same as it was before: this points to the<br> alarm and especially interlock values being to conservative or in many cases<br> counter-productive as they'll shut off the detector and could result in a junk<br> run prematurely.<br> <br> Personally I would remove quite a few interlocks and loosen many of the alarms,<br> but that decision should come from the detector exports.<br> <br> ----- Original Message -----<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #8ae234; padding-left: 1ex;"> From: "Valery Kubarovsky" <vpk@jlab.org><br> To: "Tyler Lemon" <tlemon@jlab.org><br> Cc: rich@jlab.org, "dsg-rich" <dsg-rich@jlab.org>, "Marco Mirazita"<br> <Marco.Mirazita@lnf.infn.it><br> Sent: Sunday, October 14, 2018 11:02:15 AM<br> Subject: Re: [Dsg-rich] [Rich] rich air flow<br></blockquote> <br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #8ae234; padding-left: 1ex;"> Hi Tyler,<br> Look at zoom picture. Do you understand this behaviour?<br> I mean this sharp drop of the pressure.<br> Valery<br> <br> <br> <br> <br> From: "Tyler Lemon" <tlemon@jlab.org><br> To: "Valery Kubarovsky" <vpk@jlab.org><br> Cc: "Marco Mirazita" <Marco.Mirazita@lnf.infn.it>, rich@jlab.org, "dsg-rich"<br> <dsg-rich@jlab.org><br> Sent: Sunday, October 14, 2018 10:28:51 AM<br> Subject: Re: [Rich] [Dsg-rich] rich air flow<br> <br> <br> <br> Hi Valery,<br> <br> I agree, the plot looks normal after 18:40 on October 13.<br> <br> Attached is the same plot you shared, but with annotations showing the pressure<br> measurement any time the value looked to be under 40 psi. The lowest it seems<br> to have gotten was ~36 psi.<br> <br> Also, the archiver doesn't ever show that the hardware interlock for the air<br> pressure ever tripped. It's low limit is set to 35 psi.<br> <br> Best regards,<br> Tyler<br> <br> <br> From: "Valery Kubarovsky" <vpk@jlab.org><br> To: "Tyler Lemon" <tlemon@jlab.org><br> Cc: "Mirazita Marco" <Marco.Mirazita@lnf.infn.it>, rich@jlab.org, "dsg-rich"<br> <dsg-rich@jlab.org><br> Sent: Sunday, October 14, 2018 10:15:03 AM<br> Subject: Re: [Rich] [Dsg-rich] rich air flow<br> <br> Hi All,<br> I got several calls yesterday evening and today night from CLAS12 shift about<br> AIRPR1 alarm (currently minimum set to 35). See attached plot. I changed this<br> limit to 30 for a moment. The plot looks not normal before Oct.13 18:40 in my<br> view.<br> Regards,<br> Valery<br></blockquote> <post-storm.png><br> <pre-storm.png><br> <overview.png><br></blockquote></blockquote><hr><br>Dsg-rich mailing list<br>Dsg-rich@jlab.org<br><a href="https://mailman.jlab.org/mailman/listinfo/dsg-rich" target="_blank">https://mailman.jlab.org/mailman/listinfo/dsg-rich</a><br></pre></blockquote></div><br>_______________________________________________<br>Dsg-rich mailing list<br>Dsg-rich@jlab.org<br>https://mailman.jlab.org/mailman/listinfo/dsg-rich</div></div><br></div></div></body></html>