an error about reading serial port

[hengfo]

Hi,

  I have sent 5 bytes(for example: "0","2","F","1","/n") to serial port and used VISA Read. But I only can read 0.  The right result is in the second line of the read string window, The first line is void. Generally speaking, "02F1" should in the first line,then I can read them correctly. The following picture is the result.

  Thank you!

帖子被hengfo在09-17-2007 03:57 AM时编辑过了

[simon76]

Hi hengfo,

Are you try to doing a com port loopback test?? Can you send your vi if any for better understanding of your problem.

regards,

Simon

[martin.kretschmar]

Hello,

you should add a flat sequence with some extra e.g. 50ms delays between the visa writes and reads, that helped us a lot.

You should also specify a large enough buffer. And don't forget to send the terminating CR and LF.

[hengfo]

Thank you! I delay 100ms and the problem has been solved. But what is CR and LF?

[martin.kretschmar]

Hello,

the CR and LF are in the string constants section. CR is the "Carriage Return" (arrow down and left) and the LF is the "Line Feed" (arrow down).

[hengfo]

I see. Thank you very much!