I work to communicate via rs485-usb converter with 2 energy analyzer. Baudrate:9600 Character size:8 Stop bits:1 Parity:none.Sometimes it give the error 701 and error 811 during communication.
Sometimes it give about 4-5 hours this errors. And generally this error being in same register address.
What it think about that issue? Can you have any suggestion?
May depend in multiple causes.....
But first, update VEE to actual version 9.32, and update IOLib . There was some issue with iolib and ser in the past.
second, reduce the amount of buffer in the prefs for the ser line. normally you are using 4096, if you use minimum of 32 you will see earlier this error, or it will disappear.
Then, it is recommended to reset the ser after some time, so that you are sure that it is clear ;-)
Regarding USB to ser converter, there was some issue with software illegal copy of firmware, check if you do have correct converter.
And finally , sometimes it is just a matter of broken cable or solder joint,
You may check for this with the io monitor to get more valueable info.
And there is a pdf at keysight/agilent website which explains in more detail the use if ser. Please check.
Good luck!