Good work Ennova. Looks like the USB-RS485 Converters are working fine(EDIT) Maybe its not working, i can't see if they are sent or recevied messages. Try the following anyway (EDIT). I can see messages in the screen dump you provided. Now to make things clearer for debugging, un-check the speed the current tick boxes. This should get rid of all of the 'polling' .i.e the constant stream of messages. Now you should only see messages appear when you click start and stop or change the spindle speed. Can you provide a screen dump with a few of these messages. for example, after you have turned off the other messages, clear the serial monitor window, click 'Spindle ON' button and see what messages appear in the serial monitor. Post that screen dump.