[Halld] PSS testing

[Joshua Ballard]

Hi All,

This is probably related to the dark room DC power supply issue Bobby corrected Monday.  You can actually see a similar offset on the Humidity sensors.

While investigating the recent breaker trips, we discovered that one of the laptop-style DC power bricks (24 VDC) used inside the dark room was wired in parallel with the PLC DC power supply (24 VDC).  On Monday morning, Bobby isolated the power supplies, which seems to have caused an offset in the excitation voltage for the environment sensors and/or an offset in the signal voltage that goes back to the PLC.

Bobby is investigating.

Thanks,

Josh




________________________________
From: Halld <halld-bounces at jlab.org> on behalf of Alexander Somov via Halld <halld at jlab.org>
Sent: Tuesday, February 25, 2025 4:40 PM
To: halld at jlab.org <halld at jlab.org>; Timothy Whitlatch <whitey at jlab.org>
Subject: Re: [Halld] PSS testing

Thanks, Tim.
I was just concerned about a potential light leak (though it’s likely not the case), as we currently can’t enter the room to check.
Cheers,
Sasha


________________________________
From: Alexander Somov <somov at jlab.org>
Sent: Tuesday, February 25, 2025 4:07 PM
To: halld at jlab.org <halld at jlab.org>; Timothy Whitlatch <whitey at jlab.org>
Subject: Re: PSS testing

Hi Tim,

Will the Hall will be reopening today ?
Also, could you confirm if the light sensors inside the dark room were recalibrated? The readings are currently between 0.45 and 0.49, whereas they were around 0.25 yesterday. I’m hoping there isn’t any light in the dark room.

Thanks,
                Sasha

________________________________
From: Halld <halld-bounces at jlab.org> on behalf of Timothy Whitlatch via Halld <halld at jlab.org>
Sent: Tuesday, February 25, 2025 3:12 PM
To: halld at jlab.org <halld at jlab.org>
Subject: [Halld] PSS testing

We just found out that the hall is closing now for PSS testing for a few hours.

Sorry for the late notice


Timothy Whitlatch, PE State of Virginia
Hall D Chief Engineer
Jefferson Lab
757-876-1766
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