Subject: Re: [sdss3-25mlog 1363] Re: 2.5m obslog 20130831 (MJD 56536)
From: Dan Long
Date: Sun, 1 Sep 2013 09:58:12 -0600
   Axis stop does give up the semaphore.  The fact that you were able to =
move the telescope by just issuing "track", appears to confirm that =
"track" will indeed attempt an "axis init" if the TCC doesn't have the =
semaphore. =20
-Dan
On Sep 1, 2013, at 9:38 AM, Kaike Pan wrote:
>=20
> On Sep 1, 2013, at 9:09 AM, Dan Long wrote:
>=20
>> Hi Garrett,
>>=20
>>  You are correct that the noise is new.  The configuration of the LN2 =
plumbing on sp1's 10L were changed this summer.  One side effect of this =
change is that it appears easier to get the pressure relief to vent when =
connecting/disconnecting the lines.
>>=20
>> Axis stop does not of itself take any axis out of closed loop.  It is =
usually some other operation like putting in the altitude pin, or =
pushing in a stop button that does this.  And yes, axis init is required =
to move it again with the TCC since the semaphore was given up.  That =
said, I cannot remember for sure if you issue a track command directly =
that the TCC won't attempt an init if it finds it doesn't have the =
semaphore.
>>=20
>> -Dan
>>=20
>=20
> Hi Dan,
>=20
>  What puzzled us is that: we thought an "axis stop" would have tcc =
give up the semaphore. After that although=20
> all axes are clear,  tcc need to get the semaphore with "axis init" in =
order to move the telescope. Yesterday=20
> evening, we moved the telescope with just  "tcc track" command without =
issuing "tcc axis init". =20
>=20
>   We know for sure that "tcc track" will not work if someone else, =
e.g. MCP, has the semaphore.  Now I
> am wondering whether "tcc track" should work  if no one else owns the =
semaphore at the=20
> moment by the original design or something has been recently changed.=20=
>=20
> -kaike
>=20
>=20
>> On Sep 1, 2013, at 7:15 AM, Garrett Ebelke wrote:
>>=20
>>> Hi Dan,
>>>=20
>>> It was the pressure relief valve at the top of the SP1 10L dewar, =
but its
>>> very intermittent and made more of a mechanical sound like the =
solenoid
>>> was leaking or something. It is a little hard to describe, but it is
>>> definitely new.
>>>=20
>>> Regarding the axis stop, I thought that axis stop would kick the =
telescope
>>> out of closed loop and if you wanted to move it again, you would =
need to
>>> hit axis start. Karen, Kaike and I all discussed this while at the
>>> telescope and we came to the same conclusion, that once you hit axis =
stop
>>> you would need to hit axis start before you could move the =
telescope.
>>>=20
>>> Thanks,
>>>=20
>>> -Garrett
>>>=20
>>>=20
>>>> Hi Karen,
>>>>=20
>>>> I'm pretty sure the noise you are describing is the pressure relief
>>>> venting (a buzzing oscillation, but not quite what I would describe =
as
>>>> an electrical whine) when the line is jostled =
connecting/disconnecting
>>>> the 180L dewars, but someone will check.
>>>>=20
>>>> As for axis stop, it won't set the brakes in and of itself.  It =
just
>>>> brings the axes to a stop, leaving them live but stationary  (like =
"h"
>>>> on the mcp menu) and releases the semaphore.  If you don't want the
>>>> axes live, you must push a stop button.
>>>>=20
>>>> 		Cheers,
>>>>=20
>>>> 		   Dan
>>>>=20
>>>>=20
>>>>=20
>>>> On Sep 1, 2013, at 6:21 AM, kinemuchi@apo.nmsu.edu wrote:
>>>>=20
>>>>>=20
>>>>>                    APACHE POINT OBSERVATORY SDSS 2.5M
>>>>>=20
>>>>>                              OBSERVING LOG
>>>>>                       Saturday August 31, 2013
>>>>>=20
>>>>>                               (MJD 56536)
>>>>>=20
>>>>> ----  Observing Team ----
>>>>>=20
>>>>> Garrett Ebelke
>>>>> Karen Kinemuchi
>>>>>=20
>>>>> Kaike Pan (beginning of the night support)
>>>>>=20
>>>>> ---- Observing Plan ----
>>>>>=20
>>>>> 31 Aug 2013  56536.0  0.27  02:39 11:28  18:17 03:08  BOSS  8.8 =
hours
>>>>> with first
>>>>> couple of hours for APOGEE due to lack of BOSS coverage.
>>>>>=20
>>>>> ---- Observing Summary ----
>>>>>=20
>>>>> Partly cloudy at the beginning of the night; minimal delay;  clear =
for
>>>>> most of
>>>>> the night, clouds arrived around 11:30Z.
>>>>>=20
>>>>> APOGEE OBSERVING:
>>>>> Cart 8 (Plate 5826) - 1xABBA [missing fibers #179,62; faint fibers
>>>>> #88,158]
>>>>> Cart 4 (Plate 5537) - 1xABBA + sky flats [no missing fibers; faint =
fiber
>>>>> #284]
>>>>>=20
>>>>> BOSS OBSERVING:
>>>>> Cart 10 (Plate 6295) is DONE!
>>>>> Cart 11 (Plate 6515) is DONE!
>>>>> Cart 12 (Plate 6588) is DONE!
>>>>> Cart 13 (Plate 6589) is DONE!
>>>>> Cart 16 (Plate 6530) is not done.
>>>>>=20
>>>>> APOGEE TWILIGHT OBSERVING:
>>>>> Cart 6 (Plate 6246) - 1xAB [no missing fibers; faint fibers
>>>>> #15,34,197,297]
>>>>>=20
>>>>>=20
>>>>> Problems from tonight (see details in the log and in Problems in
>>>>> Detail):
>>>>>=20
>>>>> * LN2 line connecting to SP1 dewar causes noise to a purge port =
near the
>>>>> rotator.
>>>>>=20
>>>>> * Issuing axis-stop from telescope controls and/or tcc does not =
engage
>>>>> telescope
>>>>> brakes.
>>>>>=20
>>>>>=20
>>>>>=20
>>>> .
>>>> .
>>>> .
>>>>>=20
>>>>> ---- Problems in Detail ----
>>>>>=20
>>>>> We noted that during afternoon checkout, when we detach/attach the =
LN2
>>>>> line for
>>>>> SP1, near the 10L dewar (close to the rotator) the purge port =
emits an
>>>>> electronic whine.  This happens when the LN2 line is at a slight =
angle
>>>>> to the
>>>>> connector (connecting the line directly to the port will not =
reproduce
>>>>> the
>>>>> noise).  We think the noise may be related to the grounding or the
>>>>> solenoid.  We
>>>>> do not think it will impact operations in general, but someone =
should
>>>>> take a
>>>>> look at the electronics to make sure everything is okay.
>>>>>=20
>>>>> We noted during pre-sunset checkout that issuing "axis-stop" from =
either
>>>>> the
>>>>> telescope control gui or tcc from the podium does not activate the
>>>>> telescope
>>>>> brakes.  The telescope will stop moving when we issue axis-stop, =
but we
>>>>> do not
>>>>> hear the brakes come on.  We can move the telescope without =
issuing an
>>>>> "axis-init" because the brakes never came on. We will observe
>>>>> carefully tonight.
>>>>>=20
>>>>>=20
>>>>> _____________________________________________________
>>>>> Message 1359 of sdss3-25mlog - Logs of nightly APO activities.
>>>>> =
https://trac.sdss3.org/tracmailman/browser/private/sdss3-25mlog/all/1359.h=
tml
>>>>> sdss3-25mlog@sdss3.org
>>>>> https://sdss3.org/mailman/listinfo/sdss3-25mlog
>>>>=20
>>>> _____________________________________________________
>>>> Message 1360 of sdss3-25mlog - Logs of nightly APO activities.
>>>> =
https://trac.sdss3.org/tracmailman/browser/private/sdss3-25mlog/all/1360.h=
tml
>>>> sdss3-25mlog@sdss3.org
>>>> https://sdss3.org/mailman/listinfo/sdss3-25mlog
>>>>=20
>>>=20
>>>=20
>>=20
>> _____________________________________________________
>> Message 1363 of sdss3-25mlog - Logs of nightly APO activities.
>> =
https://trac.sdss3.org/tracmailman/browser/private/sdss3-25mlog/all/1363.h=
tml
>> sdss3-25mlog@sdss3.org
>> https://sdss3.org/mailman/listinfo/sdss3-25mlog
>=20