Acquisition Computer: Deployment and Recovery

Data Logging Programs

To communicate with the LADCP, a python acquisition software is used. Each program comes also with a file containing the default parameters of the instrument:

• ladcp_wh150.py and wh150.cmd Workhorse 150kHz
• ladcp_wh300.py and wh300.cmd Workhorse 300kHz
• ladcp_bb150.py and bb150.cmd for the broad-band (BB) instrument
• wh_dnup.py, wh300_up.cmd and wh300_dn.cmd for two RDI Workhorse

All programs are in

/home/science/current_cruise_logging/

The acquisition softwares need to be edited. From the acquisition PC, open them with a text editor. The editing section is near the top and should resemble the following:

## edit this section for your cruise ###

font_size = 16                                        # try 12, 14, 16, 18, 20

backup = '/media/AC_backup/current_cruise_logging'    # 2nd copy (data and  and logs here)
## backup = ''                                        # or set to empty string to disable

device_dn = '/dev/ttyUSB0'                            # comm port
comm_baud_dn = 9600                                   # communication baud rate
data_baud_dn = None                                   # download baud rate:
                                                      #   19200, 38400, 57600, 115200
                                                      #   or None to use instrument default
cmd_filename = 'wh150.cmd'                            # default command file for WH150

##### end of section to edit ###

• There is at least one back-up disk that should be plugged onto the acquisition PC and the variable backup above should thus receive the path to that disk.

• The variable device_dn should receive the path to the USB-serial device (see Serial ports).

• comm_baud_dn and data_baud_dn are the communication and the data baud rate, respectively. To find them for the appropriate instrument, see Talking to the instrument and adjusting baud rates.

• The last line gives the file that contains the default parameters for each instrument:

  • ladcp_wh150.py should have wh150.cmd.
  • ladcp_wh300.py should have wh300.cmd

The files wh300.cmd, wh150.cmd, wh300_up.cmd and wh300_dn.cmd contain the list of default parameters for each instrument. For instance, we usually collect data from the wh150 LADCP in beam coordinates with 40x(8m) bins or 20x(16m) bins. The parameters are described in an annotated command file for wh300 . The annotations come from the manual; it is a good idea to look at the manual and understand the command files you are using.

A word on two-LADCP set-up

When two LADCPs are used, one is considered the “master”, the other the “slave”. The downlooker is arbitrarily chosen to be the “master” LADCP. In wh_dnup.py, the values of the variables device_up, comm_baud_up and data_baud_up need to be specified. Communication and data baud rate are usually the same as for the downlooker and the only difference is the name of the USB access device_up.

The master and slave configurations are given in wh300_up.cmd and wh300_dn.cmd. “master” is set by SM1, “slave” by `SM2. The command SW05000 in the master command file orders the master LADCP to ping 500 ms after the slave’s ping to avoid interference between the two pings.

Setup

Proceeding on the acquisition computer, in the current cruise logging directory /home/science/current_cruise_logging/:

• Start the acquisition program (e.g. ladcp_wh150.py) on the command line in the directory you wish to download to:

ladcp_wh150.py

Various messages appear in that window, so there’s little point in backgrounding the process. Treat the window as a console that catches error and diagnostic messages.

• If there are two instruments, the program makes two-window gui with a window on top and bottom for the up-looking and down-looking instruments, respectively. They operate independently in terms of communication to the respective instruments, but share download directory, and have ‘up’ or ‘dn’ in the filename. On netbooks, the screen may be so small that the window for the uplooker takes the whole space. Open wh_dnup.py and changes the height of the respective window in R_up.display.Text.configure and R_dn.display.Text.configure.

Prepare for data recording

Fill out the acquisition logsheet (See this example) while proceeding the following steps:

One-LADCP set-up

1. LADCP status:

   • Check LADCP communication/power cables are probably plugged in?
   • Check Power supply is off (after previous cast)?.
   • Record station number and nominal position
   • Record power supply amps drawn (per channel), if it was still on.

2. Set the station_cast string (top right corner).

3. Check PC clock (verify, if ntp; set clock if no ntp).

4. Run the steps under menu item Deploy:

• Deployment initialization:

  • Makes a “mark” in the text window and adds a time stamp
  • Sends a break
  • Asks the ladcp for its clock time
  • Lists the instrument recorder

• Set clock (sets the ladcp to the PC clock. useful if running ntpd)

• List recorder (information depends on age of instrument)

  • Check Previous station and logsheets agree with expectations?
  • Check Were there multiple file segments? all are downloaded?

• Send setup (appropriate *.cmd, in the current directory)

  • Sends each line to the LADCP
  • Queries (eg. “W?”) are included in the cmd file
  • Writes everything from the mark (see initialization) to here into a log file named after the station_cast string. (appends, does not overwrite)

• Disconnect (optional: frees up the lock on the serial port and may prevent accidental sending of a ‘BREAK’ if lines are jostled; allows use of the serial port for other things)

5. Physically deploy the instrument (see Hardware Section LADCP procedures for deployment)

Two-LADCP set-up

Run steps 1 to 4 above first for the slave (uplooker) in the TOP window and then for the master (downlooker) in the BOTTOM window. Notice that the slave will start to ping only when the master has.

Once the two LADCPs are pinging, deploy physically both instruments.

Recover the data

One-LADCP set-up

1. Run the steps under Recover:

• Recovery initialization:

  • Same as Deployment initialization: make a mark, wake up the, instrument, write PC and ladcp times and list recorder

• Download

  • Choose file from the list (consult log sheet)
  • Initiate download (automatically switches to download baud)
  • Write dialog to log file (from mark (above) to end of download)
  • Record the time the download starts and finishes
  • Put instrument to sleep
  • Check the data: in a terminal, type:

ladcp_rawplot.py --plot scalars   --show wh059_01.dat

If the raw LADCP data filename is wh059_01.dat. It will print information like the following on the screen:

Raw wh300 data file: wh010_01.dat
coords: beam

Last ensemble was 19794; 0 were bad

zmin:    -94.4  at  19021
zmax:   4506.7  at   7893
zend:    -94.0  at  19023

number_with_velocity:   16717
first_good_ensemble:     2306
last_good_ensemble:     19023

downcast:  2009/11/24 17:43:09  to  2009/11/24 19:16:15
upcast:    2009/11/24 19:16:17  to  2009/11/24 22:21:45

There are several information that need to be checked:

• Depths:

  • Are zmin and zend near 0? (within 100 m is usually OK)
  • Is zmax close to the deepest depth reached by the cast (see CTD group’s log sheet)? Note that the values are mostly positive. If there are negative, then the downward-looking LADCP thinks is looking upward. Contact us.
  • Do the times make sense?
  • Record zmax and zend on the acquisition log sheet

Note

Sometimes, depending on the LADCP firmware, a single cast will be split into multiple pieces. Evidence for this is - the fact that there are more files on the data recorder

than expected

• “zend” does not match “zstart” or “zmax” is not deep enough
• the time range for this file is not correct

The pieces can be glued abck together (example is station 059 in the LADCP demo)

2. Finalize the instrument recovery (see hardware Section LADCP procedures for recovery): once the battery is charged (drawing 0.5A/channel) toggle off power.

Two-LADCP set-up

Recovery initialization for the master (downlooker) first in the BOTTOM window, then for slave (uplooker) in the TOP window. Failure to follow that order will result in an incomplete download of the slave’s file.

Download the data for each instrument. You can start with either the slave or master and you do not have to wait that the first download finishes to start the other one.

Then, as above, scan each file and finalize the recovery.

More about files and data

• Always remember to update station and cast before starting a cast. This ensures that the dialog with the instrument is recorded in a log file with the correct station_cast information.

• The acquisition programs (ladcp_wh150.py, ladcp_wh300.py or ladcp_bb150.py) download the data from the respective instruments using the name in the instrument’s firmware.

  • temporary filenames:

    • WH150: temporary filenames are something like _RDI_000_000
    • WH300: temporary filenames are something like _RDI_000_000
    • BB150: temporary filenames are 8 digits (somehow generated inculding a timestamp) followed by 3 digits (unique to the instrument). The date is wierd, like Jan 1, 1920.

  • permanent filename:

    • the default data file name is SSS_CC using the values for SSS = station and CC = cast that were entered into the top right corner of the window before downloading started.
    • the python program will not overwrite a file that is already on the disk
    • the python program will let you rename the file to a different name (if you forgot to enter the correct station and cast before starting the download.
    • the python program will reset the date to ‘now’ at the end of downloading, so don’t delay too long saving the file when download is complete.

• backups: a copy of each log and data file is made to the backup directory specified in the python program. We’re going to standardize on /media/AC_backup/ladcp_data_backup
• reminder of strategy:
  • while steaming between stations, charge the battery and download the data to the PC
  • after download, make sure the data file is written on two media (i.e. a copy should be on a different disk or computer)
  • don’t delete any cast from the instrument until it exists in 2 other places (different media)

Additional Notes

• To quit, use the window-manager “X” to kill the whole window. There is no ‘Quit’ dialog button under any of the menus
• Other things like baud rate, port, etc can be set manually in the menus.
• To send a ‘BREAK’, look under the Command window
• “Set Time” uses the PC clock. Make sure the PC clock is very close to correct (even if using ntp) before setting the LADCP clock. It’s OK if the times are off by 1 second – that’s normal given rounding errors in the instrument.
• Disregard the following security warning in the console:

"RuntimeWarning: tempnam is a potential security risk to your program"

• On-line documentation for LADCPs is somewhere in /home/currents/rdi_docs