WTW Cond 730 Serial Communication

[VolkerL]

Hi there,

I'm new to LabView and this board. I'm really glad to be here. My name is Volker and I hope you'll be able to help me.

I work with LabView 2009 on Mac OS X 10.5.8 at my University. My task is to automate the communication between a Julabo MH-4 and a WTW Cond 730. Of course the first step is to make an interface for the communication for each of the both devices.

The interface for the Julabo MH-4 was already done, when I began to work on the project for Windows and it works well for Mac OS X, too. The problem is the interface for the WTW Cond 730.

I tried it with the basic read and write VI downloaded from the NI Website. I set the correct VISA preferences (got it from the Manual of the WTW device) and I set it to read only. The result is everytime a timeout.

After that I tried to alter the interface of the Julabo device and used a VISA write with different commands found here: http://www.wtw.com/downloads/manuals/ba72304de04_Fremdsteuerung.pdf

(English begins at the second part of the document)

(I've got commands especially for the cond 730 which differ in no relevant way from the commands in the linked document).

wtwCond730.vi

Unfortunately that doesn't work either. There are always 0 Bytes at Port. The WTW support isn't able to help further.

Very interesting is the fact, that the command: 

screen /dev/tty.UC-232AC 4800

on the Mac OS X Terminal displays the wanted information (time, date, temperature, conductivity,...) in 5 sec. intervals. Because of that, the Hardware connection seems to be working.

How can I get these informations (conductivity and temperature) into LabView? Do you see any problems in the posted VI?

Thanks a lot!

[Albert.Geven]

Hi

maybe it is not a programming error but are you using the wrong serial cable. Check this first.

and by the way you don't have to use a sequence frame for thes operations because they are all wired and the compiler will take care of the correct order.

Only when no sequence is obvious by wiring, you need such a sequence frame otherwise you may rely on seuencing by wire.

good luck 

(there are at least 2 serial cables around, straight and crossed but those can come with different control signal connections also)

[VolkerL]

Hi Albert,

thanks for your reply. I found out what caused the problems. The serial interface was not defined correctly. I've done it with the NI Configuration Wizard for Mac OS X and now I receive data from the WTW.

Nevertheless I've got another problem with the WTW LabView Interface now, which I pose in another thread in this same category. Perhaps you can help me with that! I would appreciate it.

Thanks a lot!

Best wishes from Germany