My application hangs after 10 hours in the serialport read sub-vi. Why?

[Lorand]

My application is programmed under LabView 5.1.1 on a windows 2000 platform.
I use a MOXA RS232 extending module with a B&B RS485- converter.
After 10 hours trouble-free working, the application, using semaphores, hangs in the serialport read sub-vi.
In the same constelation without RS485-converter, once the application hanged up in the serialport write sub-vi. After Restarting LabView I was still not able to access the serial port. So I had to restart the PC.

[GabbyG]

Hallo

your problem might be specific to the RS-485-converter. Hard to say from here.
One word of caution although for semphoers. The release-semaphore vi does not perform an action if you enter it with an error. So if something happend in the vi that is singled out by semaphores, you may end without really freeing the sema4. The next to access it will hang for ever if you have not selected the Timeout option.

So maybe check for that possibility.

Gabi

[Pawel Pocwiardowski]

I am not sure, but it looks for me as some buffer overflow error.
Like you read or write something before it is ready.
Try to play with the lines like DTR and so on.

regards
PP


Isildur wrote:
>
> My application is programmed under LabView 5.1.1 on a windows 2000
> platform.
> I use a MOXA RS232 extending module with a B&B RS485- converter.
> After 10 hours trouble-free working, the application, using
> semaphores, hangs in the serialport read sub-vi.
> In the same constelation without RS485-converter, once the application
> hanged up in the serialport write sub-vi. After Restarting LabView I
> was still not able to access the serial port. So I had to restart the
> PC.

[Ben]

The B&B RS-485's converters have served me well.

Are you checking for errors?
This could be the result of noise on the line being seen as data. If ther is to much noise for too long you could fill read buffers faster than they can be cleared.

Just another idea.

Ben