Date: Mon, 11 Mar 2024 17:00:55 -0600
Subject: Re: [sloan-25mlog 7083] Re: 2.5m obslog 20240310 (SJD 60380)
From: John Downey
I did do the tap this morning, glad it worked.  Now I'm wondering why
that works :D
John
On 3/11/24 14:23, Daniel Oravetz wrote:
> Hi John,
>
> It seems that either your "tap" worked, or just the threat of a "tap" was
> enough to coax the pump back into submissive compliance because the
> pressure has been dropping for the last ~5 hours (see attached) and looks
> like it's back into more typical operating values now.
>
> Dan
>
>> On 3/11/24 06:55, doravetz@apo.nmsu.edu wrote:
>>>                          APACHE POINT OBSERVATORY SDSS 2.5M
>>>
>>>                                    OBSERVING LOG
>>>                             Sunday March 10, 2024
>>>
>>>                                     (SJD 60380)
>>>
>>> ----  Observing Team ----
>>>
>>> Dan Oravetz
>>>
>>>
>>> ---- Engineering Issues ----
>>>
>>> Not really a problem, but noting it here since there have been several
>>> camChceck ionPump warnings:
>>>
>>> Since 2024-03-07 23:00Z, the b1 ion pump has been operating in the
>>> LED-bar-graph-flashing ("unlatched" I think is the term applied here in
>>> the past?) state. Grafana indicates logP=-4.94 Torr. We saw the same
>>> kind of behavior from the r1 ion pump back in September and it took
>>> about a day or so for that condition to re-latch. In this case we're
>>> going on four days now. CCD temps are holding nominal and have been
>>> steady.
>> Unfortunately, there is not a lot we can do with an ion pump when it is
>> struggling to maintain vacuum.
>>
>> The conventional wisdom is to give it a tap, but I've always found that
>> to be more of a folklore solution than one based on logic.  I'll give
>> that a try this morning however.
>>
>> I believe the pump on b1 is the other "extended life" pump we tried last
>> summer.  I was not happy with the performance of these pumps, and the
>> spares we recently bought are not the same model - those are the current
>> versions of the 2 year pumps we've used all along.  Extended life pumps
>> were supposed to give us 3 years.
>>
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>>
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