Subject: Re: [sloan-25mlog 6260] 2.5m obslog 20220915 (SJD 59838)
From: John
Date: Fri, 16 Sep 2022 14:04:32 -0600
> On Sep 16, 2022, at 1:22 PM, Audrey Oravetz  =
wrote:
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>>> -- auto-fill 180lb dewar still doesn't work, We filled in manually.
>>> -- interlock for protect the telescope from moving with a connected
>>> nitrogen line to 180lb dewar NOT WORK. So that is dangerous: there =
is
>>> possibility to move telescope with connecting to 180lb dewar.
>>=20
>> Interlock tested this morning and found to be fully functional.
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>> I do not see where the interlock event happened in the observing log =
from
>> last night (that does not mean it didn=C3=A2=C2=80=C2=99t happen, it =
means I would like a
>> time stamp to more easily find it among all the other information
>> recorded).  If this note is referring to the incident recorded in the
>> night log for September 09, that problem has been addressed already.
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> Thank you for this reminder John. Timestamps are a helpful tool when
> diagnosing issues when they arise.
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> To investigate how the Sept 9th incident was possible, we attempted to
> make the axes live with the line connected inside of the enclosure. =
The
> system rightfully did not allow it. Then, we opened the enclosure last
> night and attempted to do the same thing with the line connected, and =
the
> axes became live. Estimated time was probably between 01:30-01:55Z.
I see, I hadn=E2=80=99t realized it was a pre-observing test so I was =
looking for a note of the incident in the log of nighttime observing.
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> I can test it again tonight and provide any additional information =
that
> you may need.
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> Audrey
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Hmm=E2=80=A6. I don=E2=80=99t quite know what to make of all this.  In =
this case, the PLC should behave no differently when the building is off =
or on.
If you don=E2=80=99t mind testing again tonight, could you do so and if =
the axes all go live again, then use a jumper to go from the brass LN2 =
connector over to the stainless cryo hose past the swivel connector.  =
I=E2=80=99ll leave a jumper wire for you in the top wide drawer of the =
red tool box.
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>>=20
>> So to be clear, the message here is =C3=A2=C2=80=C2=9Cmore =
information please=C3=A2=C2=80=C2=9D.  This
>> morning I checked the state of the interlock by bringing all three =
axes
>> into a live state and then connected the 180L dewar.  The ALT and ROT =
axes
>> went OCL as they should have done.  AZ stayed live because there is =
no AZ
>> interlock related to the cryo connection.
>>=20
>> At this point, it looks as if there is no problem to me.  Having more
>> information about when the problem was seen will help me determine if =
it
>> is an intermittent one or if we really have solved it.
>>=20
>> Autofill is a related issue but harder to test easily.
>>=20
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