[Dsg-dc] DC Mix 2 Pressure Low

[Brian Eng]

So far so good after the updates.

The flow spike in the beginning was a coding error where the pressure was getting added to the regional flows making the flow way higher than it should be.

Not reflected in that plot was me just recently changing the ratios to be 20% higher/lower instead of 50% to make the cycles longer. We could think about even going to 10% if stretching it out even further is desired, but we should see what 20% looks like first.

________________________________________
From: Brian Eng <beng at jlab.org>
Sent: Tuesday, March 31, 2020 1:47 PM
To: Bob Miller
Cc: Morgan Cook IV; Denny Insley
Subject: Re: DC Mix 2 Pressure Low

Running a newer version now, hopefully this one is more reliable.

________________________________________
From: Bob Miller <rmiller at jlab.org>
Sent: Tuesday, March 31, 2020 9:25 AM
To: Brian Eng
Cc: Morgan Cook IV; Denny Insley
Subject: Re: DC Mix 2 Pressure Low

Great, thanks Brian.
________________________________
From: Brian Eng <beng at jlab.org>
Sent: Tuesday, March 31, 2020 9:20 AM
To: Bob Miller <rmiller at jlab.org>
Cc: Morgan Cook IV <mcookiv at jlab.org>; Denny Insley <dinsley at jlab.org>
Subject: Re: DC Mix 2 Pressure Low

I checked just checked and similar symptoms as yesterday, VI still running but it had lost connection between the two cRIOs.

I'll change the code some to see if that helps any.

________________________________________
From: Brian Eng <beng at jlab.org>
Sent: Monday, March 30, 2020 7:33 PM
To: Bob Miller
Cc: Morgan Cook IV; Denny Insley
Subject: Re: DC Mix 2 Pressure Low

No, the development cRIO lost connection with the gas shed cRIO. I restarted it and it went back to decreasing as expected.

If this becomes an issue I'll look into another way of communicating between the two. What it's using now was the fastest to get running, but does lack some of the error handling the more in depth ones have.

________________________________________
From: Bob Miller <rmiller at jlab.org>
Sent: Monday, March 30, 2020 7:17 PM
To: Brian Eng
Cc: Morgan Cook IV; Denny Insley
Subject: Re: DC Mix 2 Pressure Low

Hi Brian,

So I noticed that the pressure is now 112 psi and the argon flow is 1.5 x the demand.  Should the flow already be 0.5 x the demand, or is it going to wait until the 120 psi max pressure to reduce the flow?

Thanks,
Bob
________________________________
From: Brian Eng <beng at jlab.org>
Sent: Sunday, March 29, 2020 2:22 PM
To: Bob Miller <rmiller at jlab.org>
Cc: Morgan Cook IV <mcookiv at jlab.org>; Denny Insley <dinsley at jlab.org>
Subject: Re: DC Mix 2 Pressure Low

Since the system is in manual mode there's no pressure controls, the button(s) for pressure control only applies for automatic mode. With the valving the way it is automatic mode definitely won't work.

I'll make a VI to run on a development cRIO I have in the EEL to control the setpoint of Mix #2 Ar while we're in MEDCON6 so no one has to bother with trying to get the exact setpoint.

Unfortunately I'll need to send an email to one of the lists when I'm done, so if there's any fallout from that just ignore it.

________________________________________
From: Bob Miller <rmiller at jlab.org>
Sent: Sunday, March 29, 2020 1:10 PM
To: Brian Eng
Cc: Morgan Cook IV; Denny Insley
Subject: DC Mix 2 Pressure Low

Hi Brian,

Can you increase the mix 2 DC argon flow?

On Tuesday, Morgan turned off the CO2 flow, isolated Mix 1, isolated the 5000 gallon tank for mix 2, and supplied argon to the 2000 gallon tank for mix 2.

The current argon supply is 30 lpm, and the demand is also 30 lpm, however the tank pressure is 35 psi and decreasing.

We assumed that the argon flow would be adjusted by the controls to keep the tank at ~100 psi.

Thanks,
Bob
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