General Questions about using ethercat

Hello,

I mainly have a few questions about Ethercat in combination with linuxcnc. I want to retrofit a machine that i currently own and possibly some more machines in the future. I have looked at a ton of different options for motors and servo's and came across the Ethercat servo's and servo drivers from leadshine. That system looks amazing just a few small cables very fast and extremely accurate. However i don't fully understand how it works and what i need to make it work because i see some convoluted things in some videos. My main Question is what do i need to make the motors work. Just make them able to run G-code. Because in some video's i see that they use a motion controller and in other they don't like is it necessary? Or could i just plug them into the back of my pc/pi or whatever system i end up using. And the other thing that i am still trying to figure out is does anyone know the quality of the drivers and servo from omc-stepperonline? i have used there stepperdrivers and motors which are great but is their system as good as the ones from leadshine? or is it a whitelabel? 

Im sorry if any of these questions are answered already but i just was not able to find a definitive answer to them

From what i am able to gather from your question is that you dont understand how to retrofit or use linuxcnc yet. It is deffinitly something you have to put time into.

Simply said, ethercat is just a communcation protcol for your motion controller to talk to your motors. With ethercat you just use ethernet cable which simplify the hardware side. Ethercat is not new but there are deffinitly more people doing it with mesa cards (so more examples to follow).

The ethernet cable just goes into your pc or RPI. I tend to get a seccond hand pc, with a pci slot left over and put a ethernet card which will be the dedicated ethercat connection.
here and example:
For IO stuff we tend to use the beckhoff system. EK1100 with some EL1818 and EL2818 modules

As for what brand. Yes, there is a difference between brands. Leadshine is realy good, however it also comes with a pricetag. I got Lichuan servo motors for half the price. There are also Stepper motors with an integraded driver, i think omc also sell them.

i would recommend you to watch some videos and read through some topics on how things are done. Marco reps has also done some nice videos on ethercat and linuxcnc:

Thanks for the response, and indeed i am new to Linuxcnc and Ethercat. In the past i have made my own controllers etc but i want to use a bit better of a system that is why i want to switch to servo instead of stepper etc. But what i am trying to figure out is if i need a motion controller? and if so what is it used for etc etc i kinda wanna learn the ropes from using ethercat as well as linuxcnc but before buying some really expensive servo's etc just thought about putting the question out here. But thanks for the replies i will look into the video's!

LinuxCNC IS the motion controller, so EtherCAT should work without any additional controllers.

Ohh amazing that is exactly what i need to hear thanks! I think i will order a servo and driver and will start on getting to know linuxcnc some more thanks!

You are welcomed, always.

Is there a place that has instructions for new users on how to set up an ethercat machine once lcnc and ethercat is installed?

Tntmold wrote:

Is there a place that has instructions for new users on how to set up an ethercat machine once lcnc and ethercat is installed?

Not really except the sticky posts here. Ethercat works with a master and slaves (devices). There is an open source Ethercat master from Etherlab that runs on Linux. A user wrote a hal driver that allows Linuxcnc to interface with the Ethercat master. There is a licence incompatibility between Linuxcnc and Ethercat itself so we have never been able to openly support it. Plus you had to compile source code to get the master installed. In recent times, Etherlab made their master available in  a Linux repository and kindly agreed to host our hal driver on that repository, So now anybody can install Ethercat easilly and we can configure apt in our installers on the downloads page so anybody who wants Ethercat can access that repository.

Once Ethercat is installed its set and forget but the installation is more complex because you need to configure two different systems.

Thank you for the reply. Following the video on this thread, I installed the xml provided by the manufacturer but when I try to run linuxcnc I get the error:

~/linuxcnc/configs/sim.axis$ linuxcnc lathe.ini
LINUXCNC - 2.9.3
Machine configuration directory is '/home/phil/linuxcnc/configs/sim.axis'
Machine configuration file is 'lathe.ini'
Starting LinuxCNC...
libnml/buffer/shmem.cc 320: Shared memory buffers toolCmd and toolCmd may conflict. (key=1004(0x3EC))
libnml/buffer/shmem.cc 320: Shared memory buffers toolSts and toolSts may conflict. (key=1005(0x3ED))
libnml/buffer/shmem.cc 320: Shared memory buffers emcError and emcError may conflict. (key=1003(0x3EB))
linuxcnc TPMOD=tpmod HOMEMOD=homemod EMCMOT=motmod
Note: Using POSIX realtime
Found file(LIB): /usr/share/linuxcnc/hallib/basic_sim.tcl
setup_kins: cmd=loadrt trivkins coordinates=xz
Found file(REL): ./ethercat.hal
./ethercat.hal:1: lcec_conf exited without becoming ready
Shutting down and cleaning up LinuxCNC...
Note: Using POSIX realtime
LinuxCNC terminated with an error. You can find more information in the log:
/home/phil/linuxcnc_debug.txt
and
/home/phil/linuxcnc_print.txt
as well as in the output of the shell command 'dmesg' and in the terminal


linuxcnc_debug.txt contains:
13223
Stopping realtime threads
Unloading hal components

Linuxcnc_print.txt contains:
RUN_IN_PLACE=no
LINUXCNC_DIR=
LINUXCNC_BIN_DIR=/usr/bin
LINUXCNC_TCL_DIR=/usr/lib/tcltk/linuxcnc
LINUXCNC_SCRIPT_DIR=
LINUXCNC_RTLIB_DIR=/usr/lib/linuxcnc/modules
LINUXCNC_CONFIG_DIR=
LINUXCNC_LANG_DIR=/usr/lib/tcltk/linuxcnc/msgs
INIVAR=inivar
HALCMD=halcmd
LINUXCNC_EMCSH=/usr/bin/wish8.6
INIFILE=/home/phil/linuxcnc/configs/sim.axis/lathe.ini
VERSION=1.1
PARAMETER_FILE=sim-lathe.var
TPMOD=
HOMEMOD=
TASK=milltask
HALUI=halui
DISPLAY=axis
COORDINATES=X Z
KINEMATICS=trivkins coordinates=xz
Starting LinuxCNC server program: linuxcncsvr
Loading Real Time OS, RTAPI, and HAL_LIB modules
Starting LinuxCNC IO program: io
Starting HAL User Interface program: halui
Removing HAL_LIB, RTAPI, and Real Time OS modules
Removing NML shared memory segments

Please help, where do I go from here?

need hal, ini and xml files.
Sounds like something is set wrong