file: vmcm2_prep.html
11 Sep 2003

VMCM2 Instrument Checkout and Preparation for Deployment

The VMCM2 main CPU board (VMLOGR53) normally operates in RS232 mode.
See the VMCM2 Functional Description for info on changing to RS485 operation as well as the following RS485 note.

Refer to VMCM2 Commands for full command descriptions.


A potential problem was found because the value of current shunt resistor R9 is too large. There is a possibility of the VMCM2 microprocessor hanging due to switching transients on the primary supply. No SAFE value of R9 has been determined at this time!


Instrument Checkout

The following tests may be performed on the VMCM2 to confirm proper operation.

Startup and power consumption check

Status check

The VMCM2 should be running (GO mode) for this check.

Data messages

The VMCM2 should be running (GO mode) for these checks.

Configuration commands

The VMCM2 must be stopped (STOP mode) for these checks.

Several parameters on the VMCM2 are configurable, the most important being the instrument address (set by default to VM001) and the record unterval. Additionally, calibration constants for the A/D converter can be set, and a free-format checkout/cal date which displays under the STAT command may be set. All configuration commands, as well as the command to erase the FLASH memory card, are sub-commands under the UOK command. All configuration parameters are stored in EEPROM on the main CPU board. FLASH erasure will be discussed later in this document under Preparation for Deployment.

Always check the following (and set if necessary):

Test mode commands

The VMCM2 must be stopped (STOP mode) for these checks. The rotor and compass tests must be performed with the VMCM2 standing upright (sting UP).

FLASH card commands

The VMCM2 must be stopped (STOP mode) for these checks. See FB and FR commands for reference.

      Using the System Info area of FLASH

      Erasing the entire FLASH card

Preparation for Deployment

The following procedures are the minimum necessary GO - NOGO tests and final prep for the VMCM2 instrument. ALWAYS do at least these tests before putting the VMCM2 in the water!

These tests should be performed with a bench power supply set to 13.5 volts.


If you perform these test on the deployment battery just before sealing up the VMCM2 and putting it in the water, you MUST SEND A GO COMMAND at the end of the tests to resume data acquisition and data logging. Or CYCLE BATTERY POWER by momentarily disconnecting the battery; this will cause the VMCM2 to resume - REMEMBER, on power up, the VMCM2 always comes up running.

Failure to do this will make you a VERY unhappy camper at instrument retrieval time!!!

  1. Unbolt and remove the housing.

  2. Setup per the VMCM2 Operations document.

  3. Power up the VMCM2 and verify the sign-on message.

  4. Check that current consumption is approximately 10 MA at 13.5 VDC.

  5. At least one minute after power-up (with the VMCM2 running), send a STAT command.

  6. Look for reasonable response.

  7. Now send a STOP command to the VMCM2 to allow access to the full command set; you MUST send a GO command (or cycle power) at the end of the tests to resume acquisition and logging.

  8. Set your watch or clock to accurate UTC. Type in a time a few seconds in advance of the actual time; i.e. at 14:25:00, type #VM001CLOCK2002/01/15 14:25:15 where the 2002 is the year, 01 is the month, 15 is the day, 14 is the (UTC)hour, 25 is the minutes, and 15 is the seconds. DO NOT hit ENTER yet. The time is entered when you hit the ENTER key. Wait until the correct time and then hit ENTER.

  9. Send a STAT command and check the clock setting.

  10. Also in the STAT command response, confirm the averaging interval is correct (usually 60 seconds) and the FLASH card is recognized correctly.

  11. Erase the FLASH card! Even if the STAT command showed the card as empty, erase the FLASH card! Don't assume you know where the FLASH card has been. 20MB and 40MB cards are usually removed from the instrument for reading data, and other systems with different record sizes will tag used records differently!!! A card used in another system may appear empty when it is NOT - bad data storage WILL result. See Erasing the FLASH memory card earlier in this document.

  12. Briefly test the rotors, compass, thermistor pod, and A/D per Test mode commands earlier in this document.

  13. Cycle the bench power supply and repeat Steps 3 through 6.

  14. Power down and remove the bench supply and power/comms test cable.

  15. Remove the battery rail. Install a new battery with foam pads to insure a tight fit. Re-install the battery rail. Check that the compass and card retainer bars are tight. Lash down any cabling as needed.

  16. Check the o-rings and re-install the housing. Purge, install dummy plugs, etc.

  17. The VMCM2 is ready to deploy.