Lichuan A4 servo driver

An userspace program that interfaces the Lichuan A4 servo drive to LinuxCNC HAL, using RS485 Modbus RTU.

Build and install

I'm assuming you already have set up LinuxCNC, if not, go to their website https://linuxcnc.org to get started.

To download and build the driver, we need some packages:

• build-essential, C++ compiler and make
• cmake, configure the project
• git, download this Git repository
• libmodbus-dev, development files for Modbus
• linuxcnc-uspace-dev, development files for LinuxCNC

sudo apt-get install build-essential cmake git libmodbus-dev linuxcnc-uspace-dev
git clone https://github.com/havardAasen/lichuan_a4.git
cd lichuan_a4
mkdir build
cmake -S . -B build/
cmake --build build/
sudo cmake --install build/

Documentation and usage

The man page lichuan_a4.1 describes the parameter to adjust on the Lichuan A4 servo drive. It also lists the different command-line options if you need to customize anything regarding Modbus The man-page also lists the pins and signals which is used with LinuxCNC.

The provided file custom.hal is an example on how to create the signals and connect the pins to LinuxCNC.

Testing

If you want to test the servo drive, you can use one of the sample configurations that comes shipped with LinuxCNC.

• Execute the steps in Build and install, ending with installing the binaries.
• Open LinuxCNC and choose one of the sample configurations. Sample Configurations -> sim -> axis choose one of axis, axis_9axis or axis_mm.
• Say yes to copy the files to your home folder.
• Exit LinuxCNC
• Copy the custom.hal file, from the repository into the newly created configuration folder
• In the configuration folder, edit the axis*.ini file you wish to use. It's three of these, but you only need to use one of them.
• Go to HAL section and comment out HALFILE = sim_spindle_encoder.hal.
• Continuing in the HAL section, add HALFILE = custom.hal as the last entry.

License

This software is released under the GPLv2 license. See the file COPYING for more information.