Orientation Module (OM01cfg001) attached to MOBY262 (8-May2017)

See 20170508_MOBY262_OM_pre-redeploy in photos for more images

Email from Mark about the OM data collected on 8 May 2017

email date: 5/8/2017 12:19 PM

Subject: Orientation Module (OM) data

Hi Steph,

Art will be sending you some OM data to figure out how to use. The data was collected at about 9:45 HST, 8 May

The pressure data should be used as a surface correction reading which will contain some fixed biases. We should get some airport barometer data to go with it. The pressure sensor will be mounted at approximately at the same level as the MOS pressure sensor. Mike will document the measurements.

There is compass data. We collected heading at approx the 4 major compass points. Heading is aligned with the arms.

We collected some pitch data at vertical and ± 45 deg. Same for roll data. There may also be a slight pressure correction based on inclination.

There is also some accelerometer data that may be interesting to Look at someday.

Negative pitch would be tilting the arms downward. Negative roll would be rotating the buoy clockwise when facing the same way as the arms.

Mark

Email from Art with a data file attached

email date: 5/8/2017 12:51 PM

Subject: Re: Orientation Module (OM) data

Hi Steph,

Here is the output of 6 test runs with the sensor in different positions. There is a section for BSG, RSG, MOS for each run but they should all be identical.

pitch, roll, azimuth, pressure are self explanatory. forward, right, up are the accelerometer data in unknown units. The program can do averaging (std, max, min) but for this we just did single readings so those values set to defaults.

Yes, this is a sort of ugly format. Don't worry, the data will get built into the HDF files so you won't have to deal with this. This is just for testing communications with the sensor. However, Mark wanted some data from today so this is what exists so far.

Art

File: tent_test.txt

My version of the test file from 8 May

% Orientation Module (OM) data - test data from email from Art Gleason on 8 May 2107 @ 12:51pm
%
% The data was collected at about 9:45 HST, 8 May
%
%-----------------------------------------------------------------------------------
% Honolulu, Honolulu International Airport - on 8 May 2017
%DAY  Time       Air     Dew       altimeter  sea level
%  Tmp(C)  Pt(C)     RH%  (cm)    mbar
%08	10:53		27.8	19.4 	60%			76.38	1018.3			
%08	09:53		26.7	18.9 	62%			76.4	1018.4			
%08	08:53		26.1	18.9 	65%			76.4	1018.4			
%08	07:53		25.6	19.4 	69%			76.38	1018.2			
%08	06:53		23.9	20.6 	82%			76.35	1017.8			
%08	05:53		22.8	20 	    84%			76.3	1017.2			
%08	04:53		22.8	19.4 	81%			76.28	1016.7			
%08	03:53		22.8	20 	    84%			76.28	1016.8			
%-----------------------------------------------------------------------------------
%
%
% Matlab Date     pitch  roll      azimuth(deg)   forward       right  up     pressure (bar) 
08-May-2017 18:49:49   -38.782917,   0.197760,   36.370265,   2559.999750,     10.999999,  -3176.999750,   0.990899, 
08-May-2017 18:50:06    45.435344,   4.141972,   37.699596,  -2887.999750,     205.999984, -2843.999750,   0.994317, 
08-May-2017 18:50:18    0.686666,   -0.933866,   33.865367,    -47.999996,     -65.999992, -4094.999750,   0.982937, 
08-May-2017 18:50:30    7.119358,   -47.962276,  19.627077,   -507.999969,   -3020.999750, -2725.999750,   0.995540, 
08-May-2017 18:50:43    1.609546,    41.782276,  36.749279,   -113.999992,    2723.999750, -3043.999750,   0.992521, 
08-May-2017 18:50:58   -1.142613,   -0.192267,   33.359996,     81.999992,     -12.999999, -4105.999500,   0.983137, 

File: tent_test_sfmod_smaller.txt     

PS: I have not idea what the azimuth in the file is. Ken thought it was the arms compass direction. But Art said he did not collect compass data when I asked what the azimuth in the file was. So I don't have an answer to what the azimuth in the file is but according to Art it is not compass data.

Marks email explaining the pressure sensor and correction needed to get depth

email date: 5/8/2017 7:08 PM

Hi Steph,

Stephanie email to Mark about where I am at on depth corrections

email date: 5/10/2017 10:00 AM

Mark

Where I am at...

So since tilt can affect the pressure I am picking the two data points from the file that look like they are not tilted, this is the 3rd and 6th reading and getting a mean

mean([0.982937 0.983137])  = 0.983037   This will be the "deck pressure"

So I think I have what I need to get "Getting depth from bar absolute:" from your email below.

So the offset is 0.035363   (1.0184 - 0.983037)

In the absence of MOBY mooring weather data I can use the Lanai airport data for pressure. To  "correct the surface value we use to correct our at depth measurements based on atmospheric pressure when the depth measurement is taken".

The only bit I am still a bit confused on it in a previous email you said " There may also be a slight pressure correction based on inclination.".  Are you saying there is an addition correction needed to the pressure reading to get a correct depth.  Or that because the instrument is tilting up or down the depth reading will be going up or down?  I have looked online and have not found a tilt correction for pressure/depth conversion.

Steph

% Matlab Date           pitch         roll      azimuth(deg)   forward          right         up          pressure (bar)   
08-May-2017 18:49:49   -38.782917,   0.197760,   36.370265,   2559.999750,     10.999999,  -3176.999750,   0.990899,   
08-May-2017 18:50:06    45.435344,   4.141972,   37.699596,  -2887.999750,     205.999984, -2843.999750,   0.994317,   
08-May-2017 18:50:18    0.686666,   -0.933866,   33.865367,    -47.999996,     -65.999992, -4094.999750,   0.982937,   
08-May-2017 18:50:30    7.119358,   -47.962276,  19.627077,   -507.999969,   -3020.999750, -2725.999750,   0.995540,   
08-May-2017 18:50:43    1.609546,    41.782276,  36.749279,   -113.999992,    2723.999750, -3043.999750,   0.992521,   
08-May-2017 18:50:58   -1.142613,   -0.192267,   33.359996,     81.999992,     -12.999999, -4105.999500,   0.983137,   

Email from Ken about azimuth measurement and corrections applied to it

email date: 5/9/2017 1:10 PM

Azimuth is corrected for all the things it knows….which is mainly temperature I guess, as we did not do the correction for stray magnetic fields where it is mounted nor a declination correction.  The Declination correction needs to be done afterwards.

Email from Ken about the first OM data set on MOBY262

email date: 5/26/2017 10:58 AM

Well….maybe the orientation module wasn’t getting enough voltage and it is now….I am attaching the data from 5/23, and then some data from today.  The 5/23 data is what I showed yesterday, with the compass heading having a 6 second period and going +-30 degrees or so.  Today, for similar roll and pitch, the heading still has an 8 second period or so, but it is only going +-1 degree.  Much more believable….

Marks email @ 3/30/2019, 11:45 PM

OM 1 "calibration" and alignment work in progress

Orientation Drawings

(I took Marks drawings and added Mikes photos and my understanding of their relationship to MOBY) - really for OM2

Questions/Issues Stephanie still has on the OM

1. What is the configuration of this OM? It is the one from MOBY262 (OM2) or a new one.
2. Would be nice to be able to collect "shore" data with a nice output file format
3. Need to get shore data before every deployment
4. What is the T1 variable. I'm assuming time but what time??? Art answered this below
5. What are the make and model of the acceleration sensor and what are the units?
6. What is azimuth and why do the numbers never match up to MOBY. Mark said in the email for this deployment the azimuth values where bettween -180 ad 180. But I only see positive numbers but never really low number (close to 0) or very high number (close to 360). What is up with that?
7. What do we want use as a "surface" pressure for converting to depth. A fixed number is easiest but less accurate. Using Lanai airport would work but is a bit harder. And using MOBY mooring data would be hardest because we don't get data every day but in small clumps.
8. There are three azimuths (HMR2.azimuth,HMR2.azimuthC, HMR2.azimuthS) the C and S are all zero. What are these and why are we collecting them?
9. Do we need to do a pressure correction based on inclination?
10. I can not remember where we are on syncing the times for this data with MOBY. I want to make sure I converting the sample times into date/time correctly.

Info on the OM on M268

Photos of OM1 on M268

OLD NUBMERS dont use!

Mike measured the offset of the bottom of the OM from the bottom of the MOS unit to get the offset. Look like the OM is 14.5 cm higher than the bottom of the MOS can. You can also see the arrow that Mike mention Terry used to align the OM with the MOBY arms.

pre-M268 OM01 re-mount

email from Mike on 23 Sep 2019

Hello Stephanie,
Today the OM had troubles today getting power from the top controller,
so the MOS-cage shrouds were removed and the OM was disconnected.
Now, the OM01 gets power via LPJ03, at the RSPwr port.
OM comm link to the top controller is via the BS Enet cable.
And, the OM's mount position is similar to before but now,
the bottom of the OM housing is 6 inches above the bottom-end of MOS.

Note: Mark said the OM's depth / pressure reference is the end of the
pressure sensor's oil-filled tube, which is at the bottom-end of the OM housing.
However, there is a short length of oil-filled Teflon tube, which Mark installed,
which hangs outside-of and below the end of the OM housing, so this could be
the reference pressure depth.  The piece of Teflon tube is 4+3/4 inches long,
when stretched out straight.  However, this tube has a curve to it, so there
is the possibility that the reference end-o-external-oil-tube could be between
4+7/12 and 4+3/4 in below the bottom of the OM housing.  This does not
take into account the possibility that there is an air bubble somewhere in
the oil-filled-tube (this last point is my observation)...

There are new photos of this OM configuration at the NAS:
/ftp1/Mike/L285/photos/M268_pre-cal/20190923*OM01*.jpg
MF

See compliation photo below.

Mikes newly remounted OM01 meansurements

The both sides of the ruler looks to be in inches but one has a tick every 1/8th of an inche and the other has a tick every 1/12th of an inch. You need to be careful which side you are reading from because the one side starts at the end of the ruler and the other side starts at the inside of a corner of the ruler.

Measurements in the photo are my best guess since the side of the ruler used changes. Looks like they match up with Mikes numbers in the email above. So I think I have understood them correctly.

Stephanie MATH

Using the M266 measurements I add

LuBot Arm depth - Lu collector offset + dist LuBot to bottom of MOS

925.17-5.570+208.9 = 1128.5

Add 23.4 cm to get this to the Chime

1128.5+23.4 = 1151.9 (bottom of MOS to chime)

Now subtract off bottom of OM to Bottom of MOS (15.24 cm) and then add back the end of oil filled tube to bottom of OM (11.64 cm).

1151.9-15.24+11.64 = 1148.3

So if my math is right 11.483 meters is the physical depth of OM1 on M268 from the chime.

"Deck" data collected in the tent with the OM installed on MOBY268.

file on 24 Sep

---------------------------------------------
20190924_015349.mat
---------------------------------------------
Mean Roll 66.915 std 144.5559
Mean Pitch 87.989 std 0.3955
Mean Tilt 91.777 std 0.0981

Mean Azimuth 301.549 std 25.9561
Mean Acc Right -5.549 std 72.0218
Mean Acc Forward -4085.449 std 53.9375
Mean Acc Up 127.079 std 6.1405

Mean pressure 1.01626 std 0.0006

"Deck" data collected in the tent with the OM installed on MOBY268.

file on 25 Sep

The average of the two deck pressures above results in a desk pressure of 1.0159 which is subtracted to convert pressure to depth

---------------------------------------------
20190925_182044.mat
---------------------------------------------
Mean Roll 99.415 std 0.1652
Mean Pitch 79.955 std 0.0967
Mean Tilt 91.635 std 0.0233

Mean Azimuth 296.658 std 0.8485
Mean Acc Right 704.154 std 7.4253
Mean Acc Forward -4023.567 std 2.5274
Mean Acc Up 116.813 std 1.6279

Mean pressure 1.01570 std 0.0001

11 Nov 2019 emails fromnArts
answer to what is T1 (and getting time right in the OM file)

Emails 1: T1 is milliseconds. So taking the difference between them will give you the time (in ms) between the readings.

Email 2-----------------------------------------------------

Hi Steph,

OK I have some good news and bad news.

The good news is that T1 is ms from the time that the rabbit booted. Those should be accurate, so easy to get the relative time between each record in the data file.

The bad news is that getting an accurate time for when the rabbit actually booted is a bit difficult.

There are time stamps on the log file (hhmmss_run_omts.log) and on the data file (omts_hhmmss.v4dat), which should be the same by the way, and which correspond to the time that the omts program started. However, there is a built in delay after the program starts on the controller before the rabbit is turned on. This is to try to line the acquisition up with when MOS runs. Moreover, after turning the rabbit on, there are some tests of the quality of the ethernet connection, which take a minute or so. Finally, if there are problems with the connection the rabbit can be powered on/off up to 3 times to retry to get data.

My best advice is to look in the *run_omts.log files for a line like this:

20191114_030738_UTC Starting rabbit04 try X

Here, X could be 0, 1, or 2 (or maybe more if we need to try more) There may be more than one of them in any given log file (if there was a problem and it had to power cycle), so find the last one in any given file. The time stamp of this log entry will be very close, I imagine within a second at worst, of the T1 of the first line of the data file.

Another approach would be to look for lines like this:

20191114_030646_UTC Checking connection to OM

There may be more than one of them in any given log file (if there was a problem and it had to power cycle), so find the last one in any given file. The time stamp of that line will be within a few seconds of when the rabbit booted. (so when T1=0).

Alternatively, you could search for lines like:

20191114_030741_UTC Turning off OM

which will be within a second or so of the last line of the data file. But again - there might be more than one "Turning off OM" message.

You should be able to find sets of these lines, actually. For example in 20191114_030604_run_omts.log there are two sets:

20191114_030646_UTC Checking connection to OM
20191114_030738_UTC Starting rabbit04 try 0
20191114_030741_UTC Turning off OM

20191114_030907_UTC Checking connection to OM
20191114_030957_UTC Starting rabbit04 try 1
20191114_031458_UTC Turning off OM

See how the first pair is only about 1 min apart, but the second pair is almost 6 min apart. This is because there was no connection after booting the first time, so it power cycled, then was able to connect then ran for 5 min the second time. So, checking the gap between these time stamps will let you know when the data were taken. They also will bound the measurements in the data file. You'll know that if (Turning off OM - Checking connection to OM) is < 6 min then you do not have a complete data file at that time.

If there are not all three entries (Checking connection, starting rabbit04, Turning off OM) then one of two things is going on: (A) the modem has cut off before data were fully uploaded - this is normal and the complete file will be fixed next time data are uploaded. Or (B) the program or controller crashed for some reason before it was finished acquiring data.

Apologies - this is more of a hassle than it should be I know. The problem is mainly that we have fiddled with this so much to get it to work so there are some band-aids in there that make it hard. One solution is we could modify the Rabbit program to print the time at the start and or end of dumping the data. I'm not sure that is worth the hassle of having to re-upload to the rabbits - maybe. I think if you go with the "Starting rabbit04 try X" time you will be close enough for the purposes of this time series.

Art

MOBY269

MOBY tent data

Email from Mike

1/3/2020, 9:02 PM

Hello,
iBet Terrence already told you this today, butt if not...

Today, Friday, Terry temporarily mounted the OM vertically on the MOS frame
so it will be in this orientation during this weekend's M269 runs.
<attached: 2020010301, 02_OM=vertical-sm.jpg>

Cheers, MF

1/6/2020, 9:32 PM

1/8/2020, 5:49 PM

Depth of the end of the OM oil tube

%                                                                            |The bottom of the OM is 22+11/16 inches | plus the 
%                                       from chime to bottom of mos          |up from the bottom of MOS               | 4 7/12 inches down to the end of the oil tube
PHYSICAL_DEPTH = 10.7901;   % M269 depth (132.4+398.6+384.8+208.7+0.234)./100 - 55.88./100                               +10.16./100;


From Mikes M269 measurement I get the depth from the chime to the bottom of MOS.  Mikes email on the 1/6/2020 tells me the 
bottom of the OM is 22+11/16 inches from the bootom of MOS.  And Mikes measurement from M268 says the oil filled tube is 
4+7/11 inches down from the bottom of the OM.  Giving me a OM oil tube depth of 10.7901 meters

MOBY270

MOBY tent data

11 May 2020, 12:01 PM

14 Jul 2020, 11:13 AM - update from Art on M270 OM tent data

14 July 2020