Timeout Expired error for RS485 loopback test

[little_tail]

Hi everyone,

When I was doing a loopback test for a B&B USB to RS-485 mini-converter (4 wires), I am getting the meassage like

"Read Operation
Error
VISA:  (Hex 0xBFFF0015) Timeout expired before operation completed. "

The loopback test was performed with NI MAX,  and the steps are exactly follow the NI tutorial in the following link

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA03q000000YFtECAW&l=en-US

I varied the byte to read numbers and timeout vaules, but I got the same error.  

I am pretty new to the instrument control.  Does anyone have any idea about this?  Do I need to get a new RS485 connector?  Thanks.

By the way, I did a similar loopback test for a RS232 connector and it work.  

[Reyquaza]

It looks like your connector is failing the loopback test. Make sure you have the connections correct (they're different for RS 232 and RS485), and check with a different RS485 connector if you can. I believe you will need a new RS485 connector.