11 Feb 2003
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 RS485 note
at the end of this document.
Refer to VMCM2 Commands for full command descriptions.
The following equipment should be available:
- Computer running a terminal program (ProComm Plus recommended) with RS232 output set for 9600, N, 8, 1.
Run with caps-lock ON.
- Power supply with output of 12-15 vdc and capacity of 100 ma. Make sure that the polarity
is correct otherwise the VMCM2 may be damaged!. A meter in series with the VMCM2 power
supply is recommended to monitor the supply current (about 10 MA is typical after the
sign-on message has been sent).
- A VMCM2 RS232 adapter cable to connect from a DB9 Male RS232
on your PC to the 4-pin Molex that terminates the standard VMCM2 power/comms cable. This adapter
includes a 2-pin Molex connector can mate to a standard VMCM2 battery or power supply adapter cable.
Make sure the power supply is OFF. Hook up everything, start the terminal program and get it setup for
the correct COM port and 9600 baud, N, 8, 1 operation. Power up and check for power consumption of less
than 50 MA at outset. Within a few seconds, you'll see a sign-on message, and once the "Running" message
appears (up to 15 seconds after the initial message), the current consumption typically drops to about
10 MA with the supply set for about 13.5 VDC.
The VMCM2 (like ASIMET) has a communications protocol based on the SAIL (Serial ASCII Interface Loop)
protocol developed at Oregon State University. The module is interrogated by sending commands with the
following format (always with capital letters and terminated with a RETURN <cr>):
The STAT command will display several lines of
status info about the instrument.
On power up, the VMCM2 will always come up running and logging as last configured (the
STAT command will indicate Sampling GO when
the VMCM2 is running).
NOTE that only a subset
of the commands is available while the VMCM2 is running. The H
command will indicate which commands are available depending upon the GO / STOPPED state of the VMCM2.
Refer to VMCM2 Commands document for full command descriptions.
Deployment Quick Start
For the complete discussion of VMCM2 instrument preparation for deployment, refer to the
VMCM2 Instrument Prep document.
The important steps are:
- Check the basic operation of the instrument.
- Startup looks normal on the attached PC/terminal.
- After a minute (RI set to 60 seconds), D
and E commands give reasonable results.
- With Sampling STOPPED, T commands give reasonable results.
- Set the clock if necessary (CLOCK command).
- Erase the FLASH memory card and see that the correct size is recognized.
- F commands to access FLASH card.
- UOK command to access
FEOK full erase command.
- Be sure everything returned by the STAT command looks correct - especially
Sampling GO if youi are already running on the deployment battery!!!
- The deployment battery is a NEW battery, right?
- NOTE: If you did a complete deployment prep per the VMCM2 Instrument Prep
document, you can wait to connect the deployment battery until shortly before deploying the VMCM2;
Remember that the VMCM2 will ALWAYS power up RUNNING and LOGGING to FLASH memory.
- Seal up the VMCM2 with good O-rings and go....
RS232 to RS485 converters
- Black Box, Inc. sells 2 converters that work well. The first is a
PCMCIA/RS485 port (Part# IC114A, $199). This unit works well on laptops with PCMCIA slots but
does not suppress the transmissions (you see two sets of what happens).
- The second is a standalone unit (Part# IC108A, $259). This unit works well on the bench.
The settings for the IC108A standalone unit are as follows (* indicates default):
XW1A DCE *
W8 B-C 2-wire
W15 A-B * RTS/CD enabled
W5 A-B * RTS/CTS delay normal
W9 RTS/TCS delay C* 0 msec
W17 D 0.7 msec time driver remains enabled after a low-to-hi transition
W16 B * 0.1 msec Turnaround delay
S1 OUT * Normal
S2 OFF * RS-485 receiver Unterminated
S3 OFF * Line Bias Off
term 1, Rx B+ (connect to 3, Tx, B+) to the +485 (orange)
term 2, Rx A- (connect to 4, Tx, A-) to the -485 (brown)
term 3 Tx B+
term 4 Tx A-
- An RS485 adapter cable connects from a DB25 Male RS232
on the Black Box IC108A to the 4-pin Molex that terminates the standard VMCM2 power/comms cable.
This adapter includes a 2-pin Molex connector can mate to a standard VMCM2 battery or power supply