Follow up thread

Large Binocular Telescope Mail - SX M3 is making most of the noise in the OVMS+ OPD prediction
3/16/16, 9:29 AM
Al Conrad <aconrad@lbto.org>
SX M3 is making most of the noise in the OVMS+ OPD prediction
6 messages
John Hill <jhill@as.arizona.edu>
To: ovmsplus@lbto.org
Cc: John Hill <jhill@as.arizona.edu>, telescopework@lbto.org, hzuo@lbto.org
Tue, Mar 15, 2016 at 8:46 PM
Dear LBT,
Tonight we've been running OVMS+ in Mode 3 which saves the
predicted motion for the individual mirrors. The interesting result
is that both the noise spikes and the low frequency noise in the OPD
prediction seem to be coming from SX M3. See the attached plots (3.2
UT), however note that there are times (3.6 UT) when this noise is not
present. One plot is 360 sec long, and the other is 36 sec long. This
data was taken when the telescope was tracking 90deg out of a 10 m/sec
wind at a high elevation. SX M2 was collimating every 5-6 sec, and
the other 3 mirrors were not moving.
Ciao,
John
P.S. to Kellee: You can go back to Mode 1 for Wednesday night and following.
-Dr. John M. Hill
Large Binocular Telescope Observatory
jhill@as.arizona.edu
University of Arizona
phone: (520) 621-3940
933 N Cherry Avenue
fax: (520) 626-9333
Tucson, Arizona 85721-0065
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Large Binocular Telescope Mail - SX M3 is making most of the noise in the OVMS+ OPD prediction
3/16/16, 9:29 AM
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Jörg-Uwe Pott <jpott@mpia.de>
To: John Hill <jhill@as.arizona.edu>, ovmsplus@lbto.org
Cc: telescopework@lbto.org, hzuo@lbto.org
Wed, Mar 16, 2016 at 2:26 AM
Interesting indeed.
This does not sound directly like a failure of the OVMS+ sensing or processing, but indeed like real mirror motion (so
should be detectable on phasecam if it occurs).
I do see the M3 spikes only on the SX side, but I cannot confirm this for the ~1-2Hz oscillation of 4-5micron peak-topeak, that is there on M3, but on both sides, and pretty much in phase (look at UT3.1838). this oscillation goes away
completely at UT3.6 ? (could you send a similar plot)
thanks
ju
On 16.03.2016 04:46, John Hill wrote:
Dear LBT,
Tonight we've been running OVMS+ in Mode 3 which saves the
predicted motion for the individual mirrors. The interesting result
is that both the noise spikes and the low frequency noise in the OPD
prediction seem to be coming from SX M3. See the attached plots (3.2
UT), however note that there are times (3.6 UT) when this noise is not
present. One plot is 360 sec long, and the other is 36 sec long. This
data was taken when the telescope was tracking 90deg out of a 10 m/sec
wind at a high elevation. SX M2 was collimating every 5-6 sec, and
the other 3 mirrors were not moving.
Ciao,
John
P.S. to Kellee: You can go back to Mode 1 for Wednesday night and following.
--------------------------Dr. Jörg-Uwe Pott, jpott@mpia.de
Astronomer & Instrument scientist
Max-Planck Institut für Astronomie, Heidelberg, Germany
http://www.mpia.de/homes/jpott/
Phone: +49-6221-528-202
Fax: +49-6221-528-339
https://mail.google.com/mail/u/0/?ui=2&ik=4a7a930083&view=pt&sea…iml=1537d87f2ec5a8d3&siml=1537f0915bb05f9c&siml=1537ff2e29f7410c
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Large Binocular Telescope Mail - SX M3 is making most of the noise in the OVMS+ OPD prediction
3/16/16, 9:29 AM
Böhm, Michael <michael.boehm@isys.uni-stuttgart.de>
Wed, Mar 16, 2016 at 2:30 AM
To: John Hill <jhill@as.arizona.edu>, "ovmsplus@lbto.org" <ovmsplus@lbto.org>
Cc: "telescopework@lbto.org" <telescopework@lbto.org>, "hzuo@lbto.org" <hzuo@lbto.org>
Dear John,
Dear All,
I have looked at the sequences indicated by Phil in his email, and I can confirm that the problem is due to bad signals
from M3_SX. (see attached Plot from UT 2016-03-09).
To be specific, it seems OVMS-SX-M3-2 is not working properly for some reason. It is connected to the UEI
RackTangle on slot 2, channel 3. For completeness, I have also checked the x and y sensor of M3-SX (not in the
plots). These signals are definitely good.
For March 5, this cannot be seen, however.
Best regards,
Michael
-----Ursprüngliche Nachricht----Von: John Hill [mailto:jhill@as.arizona.edu]
Gesendet: Mittwoch, 16. März 2016 04:46
An: ovmsplus@lbto.org
Cc: John Hill <jhill@as.arizona.edu>; telescopework@lbto.org; hzuo@lbto.org
Betreff: SX M3 is making most of the noise in the OVMS+ OPD prediction
[Quoted text hidden]
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Jörg-Uwe Pott <jpott@mpia.de>
Wed, Mar 16, 2016 at 3:19 AM
To: "Böhm, Michael" <michael.boehm@isys.uni-stuttgart.de>, John Hill <jhill@as.arizona.edu>, "ovmsplus@lbto.org"
<ovmsplus@lbto.org>
Cc: "telescopework@lbto.org" <telescopework@lbto.org>, "hzuo@lbto.org" <hzuo@lbto.org>
Before I wrote that based on Johns plot the sensing and OVMS processing seems fine, since only M3 makes
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Large Binocular Telescope Mail - SX M3 is making most of the noise in the OVMS+ OPD prediction
3/16/16, 9:29 AM
problems. However, Michael is right, that because only one sensor seems to produce the odd behaviour, it is probably
the sensing part which is unstable.
- if you do not look at the OVMS+ output (which combines all sensors from one mirror), but at the individual sensor
data (the so-called classic OVMS channels), it does seem that also in H0G0 mode there is an issue with the sensing
for specific sensors, so the M3 noise features seem to neither be real, nor come from the OVMS+ code, but from the
sensor itself
- this can be (i) the sensor, (ii) the cable, (iii) the plugs, (iv) the analog-to-digital conversion within the Racktangle of
that specific channel
- being transient in time, it could be simply a loose connection (ii) or (iii), but (iv) should not be ruled out (unfortunately
the UEI part seems full of bugs, see the previous discussions on using the H1 mode)
- I guess it is useful to keep the Racktanle in mode 3 for a while, to confirm that only M3-SX (and in fact a single
sensor) makes these problems
- there is a spare cable for each mirror, so you might consider using that spare cable on the faulty sensor indicated by
Michael
- the OVMS+ code uses only the three z-sensor for each mirror, so you could connect the faulty sensor to the M3-SXx or y channel, and check if the transient behaviour goes away.
- question to LBTO: can you confirm when looking at the classic OVMS channels at the relevant times, that Michael's
statement below on the faulty sensor is correct? If you can than you can switch channels at UEI and check for signal
improvement right away, since the classic channels are always active. It is a bit more complicated (but doable) to remap the channels properly in software, so that the OVMS+ code takes into account different channels.
- j-uwe
On 16.03.2016 10:30, Böhm, Michael wrote:
Dear John,
Dear All,
I have looked at the sequences indicated by Phil in his email, and I can confirm that the problem is due to bad
signals from M3_SX. (see attached Plot from UT 2016-03-09).
To be specific, it seems OVMS-SX-M3-2 is not working properly for some reason. It is connected to the UEI
RackTangle on slot 2, channel 3. For completeness, I have also checked the x and y sensor of M3-SX (not in the
plots). These signals are definitely good.
For March 5, this cannot be seen, however.
Best regards,
Michael
-----Ursprüngliche Nachricht----Von: John Hill [mailto:jhill@as.arizona.edu]
Gesendet: Mittwoch, 16. März 2016 04:46
An: ovmsplus@lbto.org
Cc: John Hill <jhill@as.arizona.edu>; telescopework@lbto.org; hzuo@lbto.org
Betreff: SX M3 is making most of the noise in the OVMS+ OPD prediction
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Large Binocular Telescope Mail - SX M3 is making most of the noise in the OVMS+ OPD prediction
3/16/16, 9:29 AM
Dear LBT,
Tonight we've been running OVMS+ in Mode 3 which saves the predicted motion for the individual mirrors. The
interesting result is that both the noise spikes and the low frequency noise in the OPD prediction seem to be coming
from SX M3. See the attached plots (3.2 UT), however note that there are times (3.6 UT) when this noise is not
present. One plot is 360 sec long, and the other is 36 sec long. This data was taken when the telescope was
tracking 90deg out of a 10 m/sec wind at a high elevation. SX M2 was collimating every 5-6 sec, and the other 3
mirrors were not moving.
Ciao,
John
P.S. to Kellee: You can go back to Mode 1 for Wednesday night and following.
-[Quoted text hidden]
Jörg-Uwe Pott <jpott@mpia.de>
Wed, Mar 16, 2016 at 3:46 AM
To: "Böhm, Michael" <michael.boehm@isys.uni-stuttgart.de>, John Hill <jhill@as.arizona.edu>, "ovmsplus@lbto.org"
<ovmsplus@lbto.org>
Cc: "telescopework@lbto.org" <telescopework@lbto.org>, "hzuo@lbto.org" <hzuo@lbto.org>, Jorg-Uwe Pott
<jpott@mpia.de>
Dear John et al.,
a little delta information on top:
- to keep things simple, you should consider to interchange the UEI A-D cards (can be simply pulled when the system
is powered off), and put one of the last cards (used for roving sensors, or LINC) in the slot 2, which seems to give the
faulty sensor data.
since most channels are fine, I expect that the error occurs either on these cards or in the cables. if you change the
cards as suggested here, than you dont need to mess with the channel mapping in software and can keep using the
OVMS+ OPD calculations, since that relies on the channels and slots only (the software does not know about the
physical card, it just reads channels at slots).
j-uwe
[Quoted text hidden]
Kellee Summers <ksummers@lbto.org>
Wed, Mar 16, 2016 at 8:02 AM
To: Jörg-Uwe Pott <jpott@mpia.de>, "Böhm, Michael" <michael.boehm@isys.uni-stuttgart.de>, John Hill
<jhill@as.arizona.edu>, "ovmsplus@lbto.org" <ovmsplus@lbto.org>
Cc: "telescopework@lbto.org" <telescopework@lbto.org>, "hzuo@lbto.org" <hzuo@lbto.org>
Hi All,
I have left the real-time service running in estimation mode 3 for troubleshooting.
Thanks,
Kellee
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