[Hallb-engineering] [Dsg-hallb_magnets] [New Logentry] Torus Alarm: METAL4K_DT_MAX

Brian Eng beng at jlab.org
Mon Jan 7 10:59:23 EST 2019

Looking at the data it was TR817F1 that spiked to 325 K for a single reading. The PLC updates the statistics (min/max/avg/etc) every 5 seconds. Which is why the CCM_DT_MAX was bad for 5 seconds, see attached myaPlot image.

However, the code we deployed on the cRIO worked as expected in that it was only bad for one reading before returning to the correct value. Prior versions would get stuck at 325 K.

I had thought there was some delay (setting it to >5 seconds should work) to the alarms such that 1 bad reading (they're updated every 1 sec on cRIO and 5 sec on PLC) wouldn't cause an alarm?

We can make code changes on the cRIO or PLC to try and mask these spurious readings if that's something that's desired or needed. However, we'd need to add some logic such that an actual failure would still get read out as 325 K, so it would be safer to just change the alarms since the current behavior is fairly well understood albeit it makes the plots kind of messy since it throws off the scale so much.

Hope that helps explain what happened and let us know if we should work on changing the code.

[cid:231C5586-024C-4DA6-8CDA-9AD8496E3809 at jlab.org]

Brian Eng
Detector Support Group

On Jan 7, 2019, at 8:24 AM, Tyler Lemon <tlemon at jlab.org<mailto:tlemon at jlab.org>> wrote:


I'm forwarding this email chain to the dsg-hallb_magnets mailing list so Brian and other DSG members that support the magnet can have the full story on what's been happening.

It seems to me that it's a similar problem as the 325 K error with the Cernoxes we had that Brian's fixed excitation voltage code resolved. If I remember right, the fixed-voltage code has already been applied to all Cernoxes.

Best regards,

From: Probir Ghoshal
Sent: Monday, January 7, 2019 8:10 AM
To: Ruben Fair; David Kashy; hallb-engineering at jlab.org<mailto:hallb-engineering at jlab.org>; Nicholas Sandoval; Tyler Lemon
Subject: Re: [New Logentry] Torus Alarm: METAL4K_DT_MAX

Ruben, Dave

This we have already addressed in the past and if I am not mistaking Brian E had his algorithm that sets the excitation current. The hardware (chassis) seemed to be working.
Rama, Bring and Nick can comment to get the last updated software and the result.



From: Ruben Fair
Sent: Monday, January 7, 2019 8:04 AM
To: David Kashy; hallb-engineering at jlab.org; Nicholas Sandoval; Tyler Lemon; Probir Ghoshal
Subject: Re: [New Logentry] Torus Alarm: METAL4K_DT_MAX

Tyler, Nick, Probir,

Let me know what you think about this. I have also asked Rama to comment.


From: kashy at jlab.org <kashy at jlab.org>
Sent: Sunday, January 6, 2019 7:35:02 AM
To: hallb-engineering at jlab.org; Nicholas Sandoval; Tyler Lemon; Probir Ghoshal; Ruben Fair
Subject: [New Logentry] Torus Alarm: METAL4K_DT_MAX

Torus Alarm: METAL4K_DT_MAX

• Edit
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Lognumber 3641551. Submitted by kashy on Sun, 01/06/2019 - 07:31.
Entry Makers: kashy
Last night at 1/5/2019 at 22:39 there was a 5 second period where the signal went from 4.5K to 255K.
All signals that go into this this signal jumped at this time.
But only the first one above went to 255K.
A similar alarm went off this morning at1/6/2019 at 6:16
This time it was triggered by a quick step change from 4.5 to 43K on the USHR signal.
(Neither of these can be real temperature changes so it must be something in the instrumentation)
These were false alarms. Can we find a reason and stop it from happening?
Dsg-hallb_magnets mailing list
Dsg-hallb_magnets at jlab.org
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