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Keep in mind that we're reaching the limits of my competency...

I think the typical/standard configuration is to put the LCNC stepgen in velocity mode (stepgen.N.control-type = 1), and let LCNC's PID manage getting to the target position.

I seem to recall reading a forum post a while back describing where some developers discovered (years ago) that a velocity-mode stepgen w/PID wound up being more accurate - or otherwise 'better' - than a position-mode stepgen.

So instead of using stepgen.N.position-cmd as the PID output, stepgen.N.velocity-cmd is used.  Or something like that.

How are your other axes controlled?  Velocity-mode or position-mode stepgens?

Thank you for the clarification. What can I find the EtherCAT setup instruction? I only see an example for stepper drive. The reason I want to use API, because my system is not only doing CNC motion, but it may include other sequence. I am not familiar with LinuxCNC enough.

hilinda1 wrote:

I prefer to use API for my application. Please advise. Thank you guys.  


 

That is all good and dandy, but why?
LinuxCNC has several trajectory planners that you can switch between, so why add another layer between them?
Check the docs and GitHub, you can probably add another API there somewhere, so try the Run In Place version as you can change stuff and test quickly.

Todd wrote:

I believe you can use a switch, but the switch and the PCs ethernet port need to be dedicated only to this use. If you want to also have an ethernet network/internet connection you will need a second nic on the pc for that.

 

I have not tried that recently, but it has worked for me in the past. I had two Mesa cards connected to a switch, each with its own address.

When I tried connecting other devices to that switch, (modbus tcp, etc), that did not work. Those needed an additional NIC.

Some switches do not behave. I tried using a router instead of a switch one time, that did not work either.

LinuxCNC is a fully-fledged CNC controller.EtherCAT Cia402 is supported.I don’t think you can extract any parts for your purpose.It wouldn’t make any sense anyway.

I do not know, swap is a Linux thing, so should work.

I am currently controlling 3 EtherCAT servo drivers via SOEM. I want to run some G-code with my system. I am searching a G-code interpreter and trajectory planner in C++. Then I found LinuxCNC. I read some document and video. I have some questions below.

1. Are there G-code interpreter and trajectory planner API I can call for my application from LinuxCNC?
2. Is there a way to connect my EtherCAT servo to Linuxcnc?

I prefer to use API for my application. Please advise. Thank you guys.  

 

I updated to 2.9.8 and everything seems to work well now. Thank you !

The drive is an Astraada SRV-63. There's only analog in and serial for speed mode sadly.

However shouldn't the stepgen treat it like a velocity signal anyway? As in it generates signal until it reaches setpoint, the drive will turn the motor as long as it receives steps, right? I've been breaking my head about this all day and can;t seem to figure out why is even the setpoint from LCNC choppy? The joint.2.motor-pos-cmd is the origin of the signal it seems to me and shouldn't it be a smooth slope, letting the pid loop take care of reaching the values? Can;t seem to find info on what actually happens in LCNC between something like "G0C0" and joint.x.motor-pos-cmd. A bit stumped now :|

Just a quick glance... all your spindle-index-enable signal lines appear to be commented out in the HAL file.

Maybe a double-check and possibly uncomment those lines?

Yes, possibly the drive itself is responsible for the choppy movement.

What input methods are available for velocity mode?  If the drive accepts PWM, you can change stepgens to PWMgens on Mesa cards.

You also may be able to tune the drive to run more smoothly in position mode.  Perhaps the drive permits different tuning values to be changed on-the-fly by the user via inputs (or modbus)?  This might allow you to keep the drive in position mode, but have a tight tune for Caxis and a more gentle tune for spindle/velocity mode.

What is the drive mfgr/model?

Hi all,

We got our lathe to run and have been moving on to some of the finer details.We are on Linuxcnc version 2.9.2. We are using the AXIS display and have a Mesa 7i95 board. The problem we have been having is when trying to get our machine to do rigid tapping we will get to the g-code that does the rigid tapping and it will hang. From what I've understood, we need to have the at speed signal be true for rigid tapping? We have also manually confirmed that the spindle index enable will go low when it reaches one specific point on the spindle. I was hoping that we could get some help with anything that might be causing this issue. I have attached our hal, ini, and the gcode we are trying to run on our lathe.

-jblanscett

Hi all,

I've been having an issue with my iMach3 P2-S pendant since I installed it. Basically, the thing works great. I love it.

However, it seems to stop working randomly. I can use it for anywhere from a minute to hours when it seems reset back to the LinuxCNC screen and stops working with LinuxCNC. I've tried unplugging the USB cable and reattaching it, but it doesn't seem to help.

Any ideas?

TIA

Thanks!

I also had to uncomment 
net spindle-vel-cmd-rpm-abs    <=  spindle.0.speed-out-abs

and change
#net pdnt.spindle-speed-abs whb.halui.spindle-speed-cmd spindle.0.speed-out-abs # speed cmd from motion in rpm absolute #2026.04.09
net spindle-vel-cmd-rpm-abs whb.halui.spindle-speed-cmd
 

Thanks for quick reply. I will try this? Does default rpi install have any swap enabled?