I almost finished building my Arco System and started working on electronics. I have CNC xPro V3 board with GRBL V1.1. I use GrblControl software. I didn't connect anything to the board. I got Error Codes 6 and 9. I found out that Error Code 6 means no homing switches are installed. I don't know that Error Code 9 means. I didn't buy any switches. I connected the board to an 24VDC PSU made for CNC routers and 3D printers. How can I fix the Error Code problems?