USB to serial - Communication problem

[MarekTheStudent]

Hello everybody,

I have written a program that communicates over two RS232 Ports with 2 instruments. This program works very fine but when I connect a Serial-to-USB converter to my PC and try to communicate over this converter (COM Port 3) my communication is very strange. The strange thing is, when i debug the program it runs without problems but running it makes serious problems. I tried to insert something like 'ProcessSystemEvents' or a 'Delay' but this takes only succes if the Delay is greater than about a half second and this is not a good solution. Someone knows a better solution? Would be nice.

Thanks

Marek S.

[jr_2005]

Have you tried adjusting the settings of the USB driver? (eg. Device Manager->USB Serial Port Properties->Port Settings->Advanced) Depending on the driver, there are usually various options that you can alter, to make the USB device more compatible with an application originally designed for RS232.

JR

[MarekTheStudent]

Hello JR,

first of all: Thanks for this good hint! ...but I think I describe the problem and solution a little more .

Before I posted here my problem, someone told me that when I use RS232 over USB, I should always put in a 'ProcessSystemEvents()' call after I have accessed RS232. I tried this before I posted here my problem but without success. Now, after you gave me your hint to look into Device Manager and to look at the advanced settings of my USB driver, it works. That's why because there is a item called "use FIFO buffer" that I unchecked and than I saw that things have changed a little (I have here a Notebook that can listen to the RS232 communication). I don't know why but it seems important to put in this ProcessSystemEvents every time after accessing the COM Port but then it works.

That's all. I thought I post the solution here cause maybe someone would need it.

Greetings

Marek S.