Hi. I Have a Folgertech Kossell 2020 Delta printer. I'm using a Marlin RC3 Firmware that was working flawlessly on the old version of the software. I have recently updated to the 3.1.1 version and started having issues with connection. Printer will NOT connect about 75% of the time. I have to reset the printer, unplug the USB, restart Simplify3D, and after a few tries or a longer power down it will connect. Once it connects the prints come out great, and finish with no issues. Also when I click on EMERGENCY STOP, printer will NOT reconnect.
Here is a screenshot of what my Simplify3D window looks like while conecting...
I do not have the same problem with Repetier. That software connects every single time.