Framing error on Com 1 but not on USB Com adapter.

[pgaastra]

Hi,

I very often get the following error at the start of running a VI.:

VISA:  (Hex 0xBFFF006B) A framing error occurred during transfer. (error -1073807253). 

I have  LabVIEW 8.2.  The error only occurs when I use the built in COM 1 serial port.  No error when I use Com 3 which is a USB to Serial adapter. 

When I run terminal programs I have no problems seeing the data on COM 1.  The device I am connected to is sending out a  continuous stream of characters.

I noticed in one posting to this forum that someone said that configuring the serial port while it's in the middle of receiving characters is a bad thing.  Anyone confirm this?  To me framing error must be generated at the hardware level and the device which is transmitting the data is well behaved and sends out genuine characters.

(if you reply to this and want more info, sorry I am going home now so see you tomorrow - I write this because I have been very impressed with the promptness and usefulness of the answers I get on this site)

[Chris G in AE]

Hey pgaastra,

It seems your framing error could be caused by at least two things: inconsistent settings between your serial device and Measurement and Automation Explorer or noise on your serial line.  You can check out the Knowledgebase article about it here.  For more trouble shooting, check out KB I Get Error Code -1073807253 When Using My VISA Read as well as the forum post  VISA: (Hex 0xBFFF006B) A framing error occurred during transfer. That should be enough to get you started, good luck!

[pgaastra]

Thanks Chris

I had read most of those references.  I had a Visa Flush IO buffer in an earlier version of my VI and still had the framing errors.  I put the Visa Flush IO after the Visa Configure Serial Port and now I don't get any framing errors. 

[Chris G in AE]

Hey pgaastra,

I'm glad everything worked for you, and thanks for posting back with your solution!

[MarvinLiu]

Hi Chris, I meet the problem these days. The 0x3FFF006B just occured on COM1 or USB com adapter. I look at the https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019L38SAE&OpenDocument=&l=zh-CN . I tried to add flush I/O buffer, the problem still occured the same code can work steady on USB com adapter. I have no idea with it.

[MarvinLiu]

Hi Chris, I meet the problem these days all the same. The 0x3FFF006B just occured on COM1 not on USB com adapter. I look at the https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019L38SAE&OpenDocument=&l=zh-CN . I tried to add flush I/O buffer, the problem still occured. The same code can work steady on USB com adapter. I have no idea with it.