1073807298 error visa write

[feilong]

hello all,

   I have a instrument that has a usb connection to computer but it seems like a internal usb-serial converter because when it plug into computer, 3 virtual COM port appears and the instrument use serial port setting to control communication.

   Then the problem comes. My vi works perfect with computer internal serial port but can't perform visa write on these virtual serial port.

   The error is:

Error -1073807298 occurred at VISA Write in COMlogger4.vi

Possible reason(s):

VISA:  (Hex 0xBFFF003E) Could not perform operation because of I/O error.

   I've noticed some posts related to USB-serial converter and I tried to alter the visa set buffer.vi and visaconf.ini, set to synchronized, set individual property rather than using visa config.vi etc. but none of them works.

  There's no error during visa config and visa read vi. And even first visa write.vi works well, but the second call of visa write in my vi returns a error.

any advice will be helpful.

feilong

[Steve.Briggs]

After the 1st Write-Read executes to you perform a VISA Clear?  This could be what's messing up your 2nd attempt at Write-Read.

If not, perhaps attaching your vi will shed some light on your issue.

[Sarah_R]

Hi feilong,

Thank you for contacting National Instruments.

Are you currently using a third party serial converter?  If you are, please take a look at this knowledgebase. If that suggestion does not solve the issue, please reference a previous discussion forum post. Please reference page 2 of this forum post.  The third post on the second page talks about a specific work around for this issue. 

Please let me know if you have any additional questions on this current.

[feilong]

Thanks guys,

   The instrument I am using dosen't have a explicit/separate USB-serial converter as it only have a usb plug connected to computer. but I think it's effectively a such a converter built into the instrument as it show up 3 serial port on my computer and the computer program just treat them as serial com to communicate.    

    It looks like after I changed to separately set the visa properties rather than using visa config, the problem have gone. Now I could write or read without any problem. But one thing different than normal USB-serial converter is, this one I just need to set baud rate  to 9600 bps in my vi but I could read data at a throughout rate about 200K bps, which make me curious.

feilong