In this case the standard Usb cable connecting pc and arduino will do.īut you can buy USB to rs485 adapter and connect to rx tx lines and it should be basicaly the same think. The comunication of mach3 with arduino will be done using uart. Doesnt matter the amount of connections the hardware protocol uses, basicaly it boils down to one comunication line for half duplpex and two for full duplex. Modbus is software protocol not hardware, so you can use it not only ower rs232 or rs485 but also let say uart usart. But if this will work for you then adding full modbus library for proper comunications shouldnt be any problem. You will end up with ability of mach3 to read input pin on arduino. This will not use any modbus library it is just proof of working.
I will describe here how to connect arduino directly to mach3 without any additional hardware.
