HAVING TROUBLE CONNECTING FLUKE HYDRA DATA LOGGER

[widelite]

I'M USING LABVIEW 7.0 AND I'M TRYING TO CONNECT SOME INSTRUMENTS (SPECIFICALLY A FLUKE HYDRA DATA LOGGER ) TO MY COMPUTER USING A RS-232 CABLE TO COM INPUT. IT APPEARS THOUGH THAT IT DOESN'T COMMUNICATE WITH THE INSTRUMENT. HOW DO I ENSURE THE INSTRUMENT IS COMMUNICATING?

[JohnM 64]

Hi widelite,

There are several options you can take to determine if your communication is occurring as you expect. The first thing I would recommend would be to go into Measurement and Automation Explorer (MAX), and communicate with the instrument from this environment. Because MAX is a sort of intermediary between the hardware and software, we can see whether or not we're getting good information from the hardware, and then we can work on getting it into LabVIEW.

To communicate with the Fluke instrument in MAX, do the following steps:

1. In the Communication window, go to My System >> Devices and Interfaces >> Ports and highlight the COM port you are using.
2. Click the "Open VISA Session" button on the toolbar at the top.
3. Go to the Basic I/O lig
ht-blue tab in the new Window that appears.
4. From here, you can execute Write functions to send commands to the device, and execute a Read to get the data back.

Once you can verify that the device is communicating with the computer, you can then use a shipping example that comes with LabVIEW to verify that LabVIEW can get the information in. The Basic Serial Write and Read.vi is a good one that you can use just to send a command to the device and read back data.

-JohnM

[widelite]

JOHN,
THANK YOU FOR THE INFO, BUT AFTER DOING SO THE DEVICE STILL WOULD NOT COMMUNICATE, I GOT AFTER EXECUTE THE READ FUNCTION. I'VE CHECKED MY CABLE TO ENSURE IT'S PROPERLY CONNECTED AND RAN A LOOP TEST TO ENSURE IT IS OK, ALL THAT IS OK.

[Dennis_Knutson]

Connect to the instrument using Hyperterminal and se if you can communicate with that. I also seem to remember that the instrument comes with software from Fluke so you shold try that as well. If you can communicate with it using Hyperterminal or the Fluke software, then you know that the cable is right and that you have the right baud rate, stope bits, parity, etc. Also, a fairly common mistake to make is to not send a termination character at the end of your command string. If the instrument doesn't see this, it won't process the command and won't have any data to send back. I also hope that you're using the driver for the Hydra. If you're not, go here and download it.

[4-wire]

I had a similar problem connecting to a Fluke Hydra's serial port until I realized that you must use a null-modem cable and not a standard serial cable. You also must make sure the baud rate, parity, etc. all match between the Fluke and your computer. I would limit the baud rate to 9600.