EthercatMotorExample

This is an example of controlling an EtherCat motor using the soem Raspberry PI library.

I worked on EtherCat motors for a time at a company. They were trying to use the SOEM library and a Respberry PI 4 to control a motor. In the end they abandoned the project. I have taken what I have figured out and made this example of controlling an EtherCat motor.

I couldn't find an example of controlling a motor using EtherCat out on the net, so I put this together. Maybe this will be helpful for someone else (maybe not).

The motor is controlled using profile position mode (where you tell the motor to goto a position and it does it without being synchronized with any other motor or from the control).

This is only a basic example and has only been tested on 1 motor (the motor had design problems making it hard to figure things out on, so there could be problems with this example as well).

What you need

You need to have a Raspberry PI 4 with a SPI W5500 connected up to it and an EtherCat motor.

See http://www.simplerobot.net for examples of how to connect up the W5500 and use the SOEM library.

I will only go into using this example and assume you have correctly connected the hardware and got the SOEM library working.

I have included some instructions for SOEM-W5500-rpi just to make things easier, but you should look at the SOEM library for details (https://github.com/thanhtam-h/soem-w5500-rpi).

Step by Step instructions

I assume you have already connected the motor as the first (and only) EtherCat device, connected the W5500 chip, and have your Raspberry PI 4 ready to go (and that it has access to the internet).

SD card

We start by making a standard RPI SD card and then changing it for our needs.

• Download the Raspberry Pi Imager from https://www.raspberrypi.com/software
• Enabled SSH (setting your login and password)
• Select the Raspberry PI OS 32-bit (must be 32-bit)
• Make the SD card
• Put the SD card in the RPI and boot
• Login to RPI

Update to the latest OS files and try on SPI

• "sudo apt update"
• "sudo apt dist-upgrade"
• add "dtparam=spi=on" to your /boot/config.txt (echo "dtparam=spi=on" >>/boot/config.txt as root)

Change the kernel to one that will work with SOEM and the W5500 chip

• "cd ~"
• "git clone https://github.com/thanhtam-h/rpi4-xeno3.git"
• "cd rpi4-xeno3/prebuilt"
• "chmod +x deploy.sh"
• "./deploy.sh"
• reboot

Building modules for the new kernel

• Login to RPI
• "cd /usr/src/linux-headers-4.19.86-v7l-ipipe"
• "sudo make -i modules_prepare"

There WILL be errors, don't worry about it :)

• Add "dwc_otg.fiq_enable=0 dwc_otg.fiq_fsm_enable=0 dwc_otg.nak_holdoff=0" to the end of /boot/cmdline.txt
• Add "isolcpus=0,1 xenomai.supported_cpus=0x3" to the end of /boot/cmdline.txt
• Add "total_mem=3072" to the TOP of /boot/config.txt
• reboot

Installing the EthercatMotorExample

• Login to RPI
• "git clone https://github.com/TheBeef/EthercatMotorExample.git"
• "cd EthercatMotorExample"

Installing the SOEM-W5500-RPI

• "cd ~/EthercatMotorExample"
• "git clone -b rpi4-xenomai-3 https://github.com/thanhtam-h/soem-w5500-rpi.git"
• "cd soem-w5500-rpi"
• "chmod +x *.sh"
• "./build.sh"

Test SOEM-W5500-RPI

• "cd test/slaveInfo"
• "sudo ./slaveinfo wiz"

Build the example