Hi all,
I have been trying to communicate with a device (vaisala hmt330) by rs232. Every thing goes fine if I use cutecom. However, I am using the unit along with other instruments, and I wanted a single program that could read the data from the separate instruments and write it all to a single data file.

I tried to write a script to accomplish the job but I'm unable to send data to the device. I can read from it but I can't make it stop sending data in order to ear commands.

This script works fine for reading the data:
#/bin/bash
stty -F /dev/ttyUSB0 19200 -cstopb cs8 -parenb -crtscts -ixon -ixoff
while true
do
cat /dev/ttyUSB0
done

But I can't find the way to make the HMT330 listen to the serial port. If I do this:
echo ANYCOMMAND\r >/dev/ttyUSB0
the HMT330 just ignores the command and remains sending data.

From vaisala the info for user is:
Bauds 19200
Parity No
Data bits 8
Stop bits 1
Flow control None

Any suggestions?
Is there any way in which I can "see" what commands cutecom is sending?
Maybe I just missing some very simple issue but I can't figure out what it can be :-(

Thank you very much for your time. I will be very grateful for any help ;-)
Ergit

Not sure if this helps but I found the Device::Modem module works well if you use perl...

cheers

Humm... Yes! Perl should have been my solution but I don't know Perl and I was trying to avoid learn it, as this serial communication should be a simple thing to do. Ironically this idea was to save me time.

Good morning all,
actually I had a development today! If I connect serial cable, then run the script and only then power-up
the instrument, in this situation I get a prompt from the device.

HMT330 / 4.05
>

New problem: in this prompt I was supposed to type commands and hit ENTER.
But when I do this, the cursor just goes to the next line and the command is
not executed.
I assume this is a problem with recognition of the "end of line" or "carriage
return"... so I tried the usual shell non printing characters:
R\n
R\r
But still don't works :-(
Any suggestions would be appreciated.Thanks,

If you don't have any luck, there's a script here called mpi (functional but alpha), even without knowing perl you should be able to hack it about and make it do what you want

cheers

What commands are you using to send data to the device? Using the echo command with the -e option will enable the standard sequences. See echo man pages for more info.
echo -e "r\n" > /dev/ttyS0

I prefer using some higher level language for serial communications then a shell script.

1 members found this post helpful.

Thank you very very much michaelk ;-)
echo -e solved my problem!

In case this could be useful to someone I'm posting the script that I'm using with a VAISALA HMT330 humidity and temperature meter.

#/bin/bash
stty -F /dev/ttyUSB0 19200 -cstopb cs8 -parenb -crtscts -ixon -ixoff onlcr
echo "Power-up the Vaisala HMT330 [ENTER]:"
read
echo -e "S\r\n" > /dev/ttyUSB0
echo -e "DATE\r\n" > /dev/ttyUSB0
echo "Enter new date [yyyy-mm-dd]:"
read "data"
echo -e "$data\r\n" > /dev/ttyUSB0
echo -e "TIME\r\n" > /dev/ttyUSB0
echo "Enter time [hh:mm:ss]:"
read "time"
echo -e "$time\r\n" > /dev/ttyUSB0
echo "Enter file name [*.txt]:"
read "nome"
echo -e "R\r\n" > /dev/ttyUSB0
while true
do
cat /dev/ttyUSB0 > $nome
done

I'm using the "Service Port Connection" and it is in RUN-mode.