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Serial Communication synchronisation with Reporting Toolkit Issue

Hi Gregory,


I have tried with Termination Character (0xD). Still code gives read error and stops after few iterations. Also the scanner is in auto-scanning mode.


Please find the enclosed vi snippet.





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Message 11 of 28
That's a timeout error. You should expect those if your scanner is not sending data. You can treat it just as you would treat having zero bytes at port.
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Message 12 of 28

Hi Gregory,


As I mentioned the scanner is in auto-scanning mode. Scanning at a constant rate. I need to run the test continuously for two-three days. But it just stops after reading only five scanning cycles. How can I synchronize the Visa Read with the scanner output.



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Message 13 of 28

Well it is only stopping because you told it to stop on any error. If that specific timeout error occurs, you should ignore it. There is a "Clear Errors" VI for this purpose. You could also increase your timeout value depending on how response you need the loop to be.


I would get rid of "bytes at port" as Crossrulz suggested, and just do the VISA read. Then you can see if number of bytes read is >0. If it is, update your read buffer, if it isn't, then do nothing.

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Message 14 of 28

Hi Gregory,

As per your recommendation, I am now using Visa Read without property node "bytes at port". I noticed that Visa Read vi only reads scanner output once. After that, it never reads. I tried with property node with Term Character. Also tried without property node, and by changing different "timeout" values. But I didn't find any output(after a single read).

Please find the enclosed snippet vi and screenshots with Highlight Execution ON.


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Message 15 of 28

Your timeout is set to 3 seconds.  Are you sending new barcodes to be read faster than that?  If you don't pull the trigger fast enough, you'll get a timeout.  Since your error wire has a shift register on it, once you get an error, it will prevent all future runs from reading.


It seems you didn't look at the advice about clearing specific errors.

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Message 16 of 28

Hi RavensFan,


Could you please suggest to me where should I put the " Clear Error" vi.

If send me a pic of the updated code, I will appreciate it.






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Message 17 of 28
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Message 18 of 28

Hi Gregory,


It works fine without error case structure.

I have to count the output from the scanner. I was using the " Bytes at Port " property node. 

If I add one more property to input property control. It doesn't count any input from the scanner. What to do?






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Message 19 of 28

I don't see how the picture you posted relates to the picture Gregory posted.

And your picture is incomplete.


You should not need Bytes at Port 99% of the time.


Have you seen Crossrulz' VI Week presentation ?

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Message 20 of 28