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Topic:   Scomm32 Tx/Event issues

By: M. G. SingletonPosted on: Mar 13 2017 at 03:32:06 PM
I am presently evaluating the Scomm32 component. Everything works fine except for two issues. The first is that it will only transmit once after the port is open. To send more data the port has to be closed and reopened again? The second problem is that no receive event is triggered even though the sent data can be read from the buffer. Have tried both access samples and both have the same faults. Running Win10 with Access 2007.
I would be very much obliged if you could offer any assistance.

By: GuestPosted on: Mar 13 2017 at 08:01:08 PM

I'm not seeing that same problem.

Using the ACCDB sample projects.

I have an RS232 loopback connector (pins 2-3 linked together) so everything that's sent is immediately received.

I Open the port. I enter a few characters into the 'send' box and click the 'send' button and the characters are immediately echoed back, with timestamp, into the 'receive' box. This shows that the data was sent and that the OnComm evReceive event is working.

I click the 'Send' button a few more times and it sends each time adding more data to the receive window.

One 'gripe' I do have is that the sample code assumes we're using Com5. There's no menu to pick which com port I want to use and there's no button to clear the RXBuffer.

By: M G SingletonPosted on: Mar 13 2017 at 10:05:25 PM
Thanks for the reply. Very strange issues, I just wanted to see if anyone else had experienced
similar problems before more investigation.

By: SupportPosted on: Mar 14 2017 at 02:14:36 PM
Hello Malcolm. Nobody else has reported this issue. Having said that, those VBA/Access sample projects are just a few weeks old so I suppose there could be a problem there somewhere. But I've tested it again and I can't reproduce a problem.

Do you have a loopback plug? Just some way to connect the TX and RX pins together. Then do what that 'Guest' said above.

By: M. G. SingletonPosted on: Mar 16 2017 at 01:25:18 PM
To Close this topic. Both issues have been resolved with my setup
The Tx problem was due to having the Overlapped property set to Yes rather than NO.
The OnComm event was because of the relative values of the InBufferSize and OutBuffersize.
Once adjusted the control works perfectly.
My thanks to Ian from Support for all his helpful suggestions in trying to resolve these issues.

By: ian at axcol dot comPosted on: Mar 16 2017 at 04:54:57 PM
Malcolm. I'm glad I could help but, to be honest, we're still not totally happy with the outcome.

It should work with OverlappedIO enabled. Obviously, in your own programs you could cause a problem if you tried but you said you were testing with our unchanged sample projects. They should work just fine with overlappedIO enabled.

The default Buffer sizes at ~32k should also work fine. I can't understand why making them smaller should allow your program to work when the default ~32k causes the program to fail.

So. If you figure that out please do let me know.


By: PhillipPosted on: Mar 23 2017 at 05:03:56 AM
I had the exact same issue. Changing the buffer sizes to something smaller fixed it. Its weird because the demo version worked fine, but the production/paid version didn't.
My set up is a Windows XP virtual machine and connecting to it via RDP from a windows 10 machine. The comm port is passed through.
It was frustrating as hyperterminal would work, so I knew that the device I was getting information from was fine.
Anyway, all sorted.

By: SupportPosted on: Mar 23 2017 at 08:23:20 PM
Thank you Philip.

What kind of serial port is it? Is it the physical port on the PC MainBoard or some add-on adapter such as USB/RS232 or PCI card or something like thyat? If it is can you give me the make/model number?


By: SupportPosted on: Mar 28 2017 at 09:09:42 PM
Just wanted to let everyone know that there is an issue with some types of serial port.

We'll release an update in a day or two.

In the meantime just make sure your buffers are set to round KB values such as 4096, 8192, 16384 etc and you won't have this problem.

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