VIsa timeout issue on different computers

[KVS2]

I am communicating with a power supply using the com port, which works fine when using a Windows 7 computer.  The same code will not work with Windows XP computers.  The code is a simple initialize routine that came with the power supply.  The error is a Visa timeout at read

[RavensFan]

Not much information to go on there.  Not even a VI to look at?

Pure guesses.  The com port is a different number on one PC from the other.

[Ranjeet_Singh]

Show us your code but otherwise it will take some time on different computers hence to get rid of it use average timeout if possible. And in the serial communication there is one unsaid rule is to use 10% extra timeout. 

[KVS2]

Here is the init VI that is giving us problems.  The com ports are going through a USB -RS232 hub (4 port).  Could the ports have different numbers even though the only change is the USB connection to the computer?  There is a diffference in the software driver version of the FTDI serial to USB driver.

Thanks

[crossrulz]

---

KVS2 wrote:Could the ports have different numbers even though the only change is the USB connection to the computer?

---

I've been some USB to RS-232 adaptors show a different COM port for each time the adapter is plugged in.

Do you have a hardcoded serial port in your code?  How are you setting your serial port to be used in the code?

[RavensFan]

Your subVI MPEInit is missing.  What you attached doesn't tell us anything meaningful without that subVI.

Yes.  Ports can certainly have different numbers on different PC's.  Did you look in Windows Device Manager to see how the ports are numbered?

[KVS2]

I have verified that the same com ports come up using the NIMAX utility (had the com ports change numbers once during development, so now I check each time when starting up) on both computers.  As for the VI, is there a method for loading all of the sub vis?  will try again.

[RavensFan]

Since much of the code is dependent on reading the Property node Inteface Information Name, put a probe or indicator on that string wire and see what it says when you run the code in Win7 and WinXP.  Perhaps the results being returned are different.  That seems like a very strange bit of code architecture, and it scares me because it requires the operating system to return a bit of information to be just so in order for the code to run properly.

Have you tried contacting whoever create this VI?

[Ranjeet_Singh]

If you use larger timeout then also you are facing same problem? The best thing you can do is to use error out and see what is the error. I dont think this is timeout issue anymore

[KVS2]

Thanks everybody.  Traced the issue to a 4 port RS232 to USB hub.  Ports do not remain constant between computers nor does the order of the 4 ports stay the same ( ie 2 computers gave com3-6, but com3 was com5 on different computers.)