cchipman

Serial port problems are usually pretty straightforward to solve. Check that you have a proper serial port cable, not a null modem cable (the receive and transmit lines are crossed in the cable) between the PC and the device. If you are on a Windows XP system, use HyperTerm (Start->Accessories->Communications->HyperTerm) otherwise, download TeraTerm (it's free - search on TeraTerm). Set up HyperTerm to use the proper COM port, and configure the baud rate, stop bits, etc. for your device. Send a command string for the device and check the response. If everything works, great. If not, start playing with baud rates and other parameters. Once you are communicating successfully via HyperTerm, then move to LabVIEW to open and configure the port, then send and receive characters Good Luck.

Thanks for the reply, but no, the code itself is pretty large and not revealing. My question is more along the lines of given this situation, what debugging techniques do you use? I have used the standard execution highlighting and single-stepping, but they don't seem to be working here. Is there any more sophisticated techniques?

Hi I am new to LabVIEW and have read "LabVIEW for Everyone". I have inheirited a non-trivial LabVIEW app to which I had to add a feature and now it does not work. Basically, within an infinite while loop (the program runs continuously), there is a sequence structure.The program runs the sequence as expected the first time through but after that, the program runs away. By that, I mean that it goes off to do some next step but I cannot find it anywhere on the block diagram. I have single-stepped all the way up to "finish sequence structure" but the next step is just gone. The sequence structure frame remains on the final sequence, the loop counter on the infinite loop does not increment. The run arrow says it is running but nothing is happening and the stepping controls no longer work. It should not be in some lower level VI but it may be. Also, highlighting execution does not show anything either. Is there some way to find where the program is executing? Thanks Colin