In my previous post on this topic I successfully managed to get LinuxCNC with EtherCat running on a Beckhoff CX2040. That was over a year ago and since then I didn’t have the time to dig deeper into the matter. Until now, and a lot has changed in the meantime …
Last weekend I attended DDos at the Odenwilusenz Hackerspace in Beringen, Switzerland. In the days before that, I planned to reactivate my setup and bring it along.
When I started the system, everything worked exactly like when I left it. So I added a Beckhoff EL1804 and as Beckhoff EL2828 just to find out that the used version of the linuxcnc-ethercat does not sopport these two types.
An attempt to update to the latest version failed. So I looked at the LinuxCNC website to check out what’s the latest version. I ran 2.8.4 and the latest release was 2.9.3 which, to my surprise now comes from a debian repo along withthe latest version of linuxcn-ethercat. And that also includes the CCAT driver which I had to build from source the last time.
So I decided to start all over and install the 2.9.3 ISO on a new CF card.
Installation 🔗
The installation was straight forward as expected. After booting the system for the first time, I got an error at the attempt to do a system update.
The reason is a missing or wrong GPG key in the sources.list
However, the recommended solution from the LinuxCNC forum didn’t work for me, but I was able to use the instructions from the Etherlab website
export KEYRING=/usr/share/keyrings/etherlab.gpg
curl -fsSL https://download.opensuse.org/repositories/science:/EtherLab/Debian_12/Release.key | gpg --dearmor | sudo tee "$KEYRING" >/dev/null
echo "deb [signed-by=$KEYRING] https://download.opensuse.org/repositories/science:/EtherLab/Debian_12/ ./" | sudo tee /etc/apt/sources.list.d/etherlab.list > /dev/null
This adds a new file called etherlab.list to /etc/apt/sources.list.d/, which requires that the original .list file is deleted.
After that I was able ti update and upgrade with
sudo apt update
sudo apt upgrade
I installed LinuxCNC and linuxcnc-ethercat from the repo
sudo apt install ethercat-master libethercat-dev linuxcnc-ethercat
Then I enabled and started the EtherCat Master
sudo systemctl enable ethercat.service
sudo systemctl start ethercat.service
That failed because I was missing configuration in /etc/ethercat.conf.
The config file requires two settings MASTER0_DEVICE and DEVICE_MODULES.
To get the MAC of eth0 which is the CCAT simply run ip a and read the MAC address from there.
I set MASTER0_DEVICE="00:01:05:1e:6b:8e" and DEVICE_MODULES="ccat"
Luckily the Etherlab master comes with prebuild ccat drivers.
After a reboot there was still no /dev/EtherCAT device 🤔
So I ran sudo systemctl restart ethercat.service and that worked.
The LinuxCNC forum recommends to add a udev rule for correct permissions, so I added /etc/udev/rules.d/99-ethercat.rules with this content:
KERNEL=="EtherCAT[0-9]", MODE="0777"
After another reboot /dev/EtherCAT was gone again. sudo systemctl restart ethercat.service brought it back.
At the time of writing this I was not able to figure out whats causing this and how to fix it other than running a sudo systemctl restart ethercat.service after every system start.
Testing EtherCat 🔗
I quickly checked if the master was running
ethercat master
Master0
Phase: Idle
Active: no
Slaves: 3
Ethernet devices:
Main: 00:01:05:1e:6b:8e (attached)
Link: UP
Tx frames: 18587429
Tx bytes: 1299386046
Rx frames: 18587422
Rx bytes: 1596784378
Tx errors: 0
Tx frame rate [1/s]: 122 121 121
Tx rate [KByte/s]: 7.1 7.1 7.1
Rx frame rate [1/s]: 122 121 121
Rx rate [KByte/s]: 9.1 9.0 9.0
Common:
Tx frames: 18587429
Tx bytes: 1299386046
Rx frames: 18587422
Rx bytes: 1596784378
Lost frames: 7
Tx frame rate [1/s]: 122 121 121
Tx rate [KByte/s]: 7.1 7.1 7.1
Rx frame rate [1/s]: 122 121 121
Rx rate [KByte/s]: 9.1 9.0 9.0
Loss rate [1/s]: 0 0 0
Frame loss [%]: 0.0 0.0 0.0
Distributed clocks:
Reference clock: Slave 0
DC reference time: 0
Application time: 0
2000-01-01 00:00:00.000000000
Nice 😎
Creating a test config 🔗
I started LinuxCNC with the sim.axis config to have a template to start with.
In the [HAL] section of axis.ini I added a HALFILE = ethercat.hal.
Next I created two new files in the same folder, ethercat.hal and ethercat-config.xml.
The first looks like this:
loadusr -W lcec_conf ethercat-conf.xml
loadrt lcec
addf lcec.read-all servo-thread
addf lcec.write-all servo-thread
The later like this
<masters>
<master idx="0" appTimePeriod="1000000" refClockSyncCycles="-1" name="master0">
<slave idx="0" type="EL1018" name="DI1"/>
<slave idx="1" type="EL2008" name="DO1"/>
</master>
</masters>
I switched my setup back to the old EL1018 and EL2008 terminals because I knew they were working in the old setup.
After starting LinuxCNC with this config I was able to see inputs in the Show HAL configuration menu under Pins -> lcec -> Master0.
Overall a very easy setup compared to what I had to do last time.
Nice work from the people at LinuxCNC , Etherlab/IgH and linuxcnc-ethercat