Noob here.
I've got an 3018 chinese cnc.
I connected it to my windows 10 PC with arduino ide / Grblctrl and I can connect to the device via USB (USB-CH340 controller).
The device "warm up" and I get the message "Grbl 1.1f ['$' for help]" in the serial monitor in IDE.
After that nothing: I can't give any command to Grbl. "$", "$$", "?" they don't produce any output.
It looks like I can't send any command to the arduino. Same problem with other programs (grbl Controls).
Any idea how to fix this?
I tried to switch USB and reboot multiple times.
A photo of the board is attached.
Thanks in advance.
Are you using a USB 2.0 port or 3.0 ?
It can on occasion make a difference and USB 2.0 is preferable.
Presume you installed the CH340 drivers correctly ?
Sometimes you need to do that as ADMINISTRATOR.
Baud rates are important in GRBL (as with any serial comms) 115200 is the normal default.
It is possible (slim chance) that the board was shipped without GRBL installed.
Most ship with 9.0 but will happily accept the better 1.1.
Bob.
ballscrewbob:
Are you using a USB 2.0 port or 3.0 ?
It can on occasion make a difference and USB 2.0 is preferable.
Presume you installed the CH340 drivers correctly ?
Sometimes you need to do that as ADMINISTRATOR.
Baud rates are important in GRBL (as with any serial comms) 115200 is the normal default.
It is possible (slim chance) that the board was shipped without GRBL installed.
Most ship with 9.0 but will happily accept the better 1.1.
Bob.
Thank you for your reply.
I think that GRBL is installed on the device cause I receive the message "Grbl 1.1f ['$' for help]".
I tried different versions of CH340 drivers.
I also tried different USB ports but I had no luck. 
1.1f is I think the latest version and also works well with lasers.
Don't forget you can only have one program using the COM port.
So if you are using the IDE's serial terminal you cannot use another program to try read or write to that board unless you CLOSE the IDE to free up the COM port again.
SO lets say you are good to go with the CNC shield / board.
Personally I use UGS or LASER GRBL for my machines.
If you use UGS then select the correct COM port and hit CONNECT.
In the lower UGS console it will give out the MSG you saw and also read back the list of parameters from the shield.
Make sure you don't have any motors etc connected to the board for the moment as we only need to check its functions. Whatever program you use will report back as if it is working but that's all we need to see for now.
Lets see if you can get that far first and if we can then you can start to attach things one by one to test them.
Bob.
I've just bought one of these and experienced the same problem.
The solution is to unplug the offline controller. USB and controller won't both work at the same time. This isn't mentioned in the instructions but is mentioned in some of the online adverts.
If you've arrived here because you're trying to get your USB to work, this may be the solution that you're looking for.
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