Frequently Asked Question

How to setup Inverter over Modbus.

myCNC Ethernet controllers contain RS485 bus connector with RTU-modbus and ASCII-modbus implemented protocols.

Modbus can be configured through configuration tab "Technology"->"Spindle"


1) Check "RS 485/Modbus communication" to enable RS485/Modbus on myCNC Ethernet controller.
2) Setup "RS485" comminication speed according your inverter settings.
3) Setup "Inverter Address" and check the first checkbox.
address value 0...15 are reserved in myCNC or non-modbus devices, Modbus Inverter address value should be 16 or more;
For 1-spindle configuration the first checkbox only should be checked. Other checkboxes are for multi-spindle configurations.

 4) For proper communication 2 write registers should be setup.

"WR/Operate" - Writing to this register defined values will turn ON rotation, direct rotation or Stop rotation.

"WR/Frequency" - Writing to this register will change inverter output frequency (spindle speed)

For number of inverter types (Delta-VFD, Mitsubishi/VD-D700, Fuling-DZB, Yaskawa V7 & V1000) you can load register addresses by pressign "Load defaults" button.


5) Defined values that "Spindle ON", "Spindle Reverse" and  "Spindle OFF" should be written on "PLC Configuration->Spindle" dialog settings. Option "Spindle inverter over Modbus" - "yes" should be choosen as well to activate sending SPindle commands over modbus.


6) Depends on Inverter model Inverter frequency unit can be rpm, 1 Hz, 0.1Hz, 0.01% or something else. MyCNC software sends spindle speed as "Spindle speed, rpm" multiplied by "speed  ratio (modbus)". This ratio should be choosen to get correct spindle speed setup for any inverter model.

For example, Inverter "Fuling DZB": speed settings unit is 0.01%, max inverter frequency 300Hz, 18000 rpm.

This means value 10 000 should e sent to get spindle frequency 18000rpm.

Speed ratio is 10000/18000=0.55556