Operation at AuxTel and Trouble Shooting

On this page, we provide instructions on how to take a night of temperature data. Normally, these data should be acquired when the Auxiliary Telescope is in operation.

The process takes about 5 minutes, and should be started around the time the first AuxTel exposures are acquired.

The code underlying this acquisition is accessible at the Stubbs Group GitHub page:
https://github.com/stubbslab/TempProbe

Instructions, in sequence:

Log onto the control computer:
1. You must have the appropriate VPN running on your computer (PSF1-LAS-UPD4-5787-config on Sasha's machine)
2. From terminal:
3. ```
ssh stubbslab@auxtel-meerkat01.cp.lsst.org 
```
4. (Enter usual stubbslab password)
Move to directory with data acquisition code:
1. ```
cd Documents/TempProbe/code/
```
(OPTIONAL) Modify the bash code variables with your choice of acquisition parameters:
1. vi TakeNightOfTempProbeData.bash
2. Variables to change (note: the sampling frequency is set to 1kHz)
  1. int_time: The number of seconds per acquired data stream
    1. typically ~60
  2. var_time: The number of seconds to measure the temperature variance
    1. typically ~10
    2. should be pegged roughly to AuxTel integration exposure time
  3. n_minutes: The total number of minutes over which data should be acquired
    1. A series of exposures of the length specified by the int_time variable
    2. Should be set to the length of the night
  4. save_freq: The inverse fraction of data to be fully saved (rather than just the measured temperature variance)
    1. Note, this is an INVERSE measurement. So save_freq=10 means 1/10 = 10% of the data will be saved, save_freq=20 means 1/20 = 5% of the data will be saved.
    2. To save all data, set save_freq=1. Note this will generate a lot of data, filling up the computer memory quickly.
Run the code:
1. ```
bash TakeNightOfTempProbeData.bash   
```
2. Note: The data files are saved with a running tally that ticks upward with every execution of the data acquisition script.
Check the first data file, to make sure the data stream levels appear reasonable:
1. You want to open the first full data file that is saved. It begins with the prefix: Arduino_7Channel
2. Example (replace with the appropriate date directory):
  1. ```
  $ ls -ltr ~/Documents/TempProbe/data/2022_06_29/Arduino_7Channel* 
```
2. ```
-rw-rw-r-- 1 stubbslab stubbslab 3017274 Jun 29 20:31 /home/stubbslab/Documents/TempProbe/data/2022_06_29/Arduino_7Channel_2022_06_29_4.csv
-rw-rw-r-- 1 stubbslab stubbslab 3016606 Jun 29 20:31 /home/stubbslab/Documents/TempProbe/data/2022_06_29/Arduino_7Channel_2022_06_29_5.csv
-rw-rw-r-- 1 stubbslab stubbslab 3016876 Jun 29 20:32 /home/stubbslab/Documents/TempProbe/data/2022_06_29/Arduino_7Channel_2022_06_29_6.csv
-rw-rw-r-- 1 stubbslab stubbslab 3107725 Jun 29 21:07 /home/stubbslab/Documents/TempProbe/data/2022_06_29/Arduino_7Channel_2022_06_29_7.csv 
-rw-rw-r-- 1 stubbslab stubbslab 3107725 Jun 29 21:08 /home/stubbslab/Documents/TempProbe/data/2022_06_29/Arduino_7Channel_2022_06_29_8.csv
-rw-rw-r-- 1 stubbslab stubbslab 3107725 Jun 29 21:08 /home/stubbslab/Documents/TempProbe/data/2022_06_29/Arduino_7Channel_2022_06_29_9.csv
```
  3. $
3. Check to make sure the data looks good
  1. vi /home/stubbslab/Documents/TempProbe/data/2022_06_29/Arduino_7Channel_2022_06_29_9.csv
  2. Here is what you should expect, by column:
    1. Column 1:
      1. Delta t hh:mm:ss
      2. The time change since the first measurement started, at the time shown in the hh:mm:ss value
      3. Should be a steadily increasing series of values, going up by 0.001 every time
    2. Columns 2-6:
      1. Ref Resistors, x-axis, y-axis, z-axis, Ref Therm/Resist
      2. The output voltages of the various voltage dividers
      3. Should be values around 0.5-0.6 V, slowly changing
    3. Columns 7-8
      1. V+, V-
      2. Should be around 1V and 0V, respectively, holding pretty steady.
  3. If these columns check out, you should be good to go. Just let it run.
  4. If any (or many) of columns 2-8 look substantially off from this, there is likely a problem.
    1. Stop the observing sequence (Control-C should be okay)
    2. Check the known issues below.

Known issues and solutions:

(Please add additional documented bugs, and fixes as they are found)

Issue 1: Permission denied issue with the ACM0 port.

Explanation: When first connected, the Arduino is not fully usable by all users (readable, but not executable, I think).

Solution: As super user, change the permissions:

        sudo chmod a=rwx /dev/ttyACM0

(Enter usual password)

Note: You may need to adjust the port number from ACM0 to ACM[Whatever number the arduino is assigned]. You can find all USB ports by: $ ls /dev/ACM?

Issue 2: Code 'hangs' while sampling from arduino.

Explanation: Laptop has lost ability to read from arduino, although it can still see that the arduino is connected over USB.

Solution: Power cycle arduino, and try again.

Issue 3: Data column(s) in acquired data are different from what is expected (see point 5c in observing sequence above)

Explanation: A electrical short likely exists in one or more temperature probe wires. Most often, this short occurs between the shield of the twisted shielded cables and the signal wires.

Solution: Open up the white box holding the temperature probe wires, and identify which wires are causing the short.

Notes:

A hint regarding which channel is causing the short might be which channel(s) are showing strange values. If either V+ or V- are off, all other values will be off too, suggesting that V+ and V- would be good places to start.

Recommended debugging procedure is to use a voltmeter to test arduino channels directly, rather than reading new data over the laptop. The voltage readings with a voltmeter should match the readings coming over USB.