[Esr-users] [New Logentry] Hall B cryo investigation and changes to allow operation of Hall B magnets

[Volker Burkert]

As always, great work by Dave!  And late at night...
Volker

________________________________
From: Esr-users <esr-users-bounces at jlab.org> on behalf of kashy--- via Esr-users <esr-users at jlab.org>
Sent: Wednesday, April 3, 2024 11:20 PM
To: esr-users at jlab.org <esr-users at jlab.org>; hallb-engineering at jlab.org <hallb-engineering at jlab.org>
Subject: [Esr-users] [New Logentry] Hall B cryo investigation and changes to allow operation of Hall B magnets

Hall B cryo investigation and changes to allow operation of Hall B magnets<https://logbooks.jlab.org/entry/4273571>

  *   Edit<https://logbooks.jlab.org/entry/4273571/edit?destination=email/send>
  *   Delete<https://logbooks.jlab.org/entry/4273571/delete?destination=email/send>

Lognumber 4273571<https://logbooks.jlab.org/entry/4273571>. Submitted by kashy<https://logbooks.jlab.org/user/kashy> on Wed, 04/03/2024 - 23:15<https://logbooks.jlab.org/entries?start_date=1712196939&end_date=1712204139&book=HBLOG&book=HBTORUS&book=CLOG>.

Logbooks:       HBLOG<https://logbooks.jlab.org/book/hblog> HBTORUS<https://logbooks.jlab.org/book/hbtorus> CLOG<https://logbooks.jlab.org/book/clog>
Entry Makers:   Kashy

I joined in the search for why Hall B is having cryo issues at 8:45pm I was logging on to my Onsite PC to limit slow internet possible issues.
I found that I could not bring up myaplots on my computer using my login mode of VDI. I'm not sure why, live plots are working

Return temps from the Buffer dewar and Torus were both running high.

Denny went to the Hall and checked BD and Torus U-tube VJ for sweat and cold. No sweat, but the BD return utube was a bit cold.
While doing this I noticed that the minimum position of the JT valve (EV8210) seemed high. I looked at the cascaded PID EV8210A (which sets the min position) I recall we had this set higher and we (denny and I looked through some PID sheets
I found that the set point for the loop was 5.5K but the current setpoint was 5.8K so the valve would tend to stay more closed and thus flow through the return u-tube would be less and thus get to a higher temp.
I also increase the minimum output of EV8210A from 30 to 41 so this could cause the Dewar to over fill but may allow us to run the Torus and Solenoid w/o tripping.

We have now gone for about 30 minutes with the dewar return temperature not bouncing over 9K but it was going to 25K every few minutes before these changes

We should now ramp up the magnets. Please call my cell if it trips again.
Dave

[https://logbooks.jlab.org/files/styles/plentybig/public/2024/04/4273571/Screenshot%20(603).png]
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mailman.jlab.org/pipermail/esr-users/attachments/20240404/5f27ec13/attachment.html>