Homing with Absolute Encoders (Again)

Hello everyone

I am having issues setting up my homing sequence for absolute encoders on my Ethercat servo dirves. I have read trough a few topics here on the forum but did not find the solution to my problem.

Background: I have Lichuan Ethercat servo drives with 23bit absolute encoders. From testing I have found out, that the encoder tracks 512 turns (-256 to +256) which combined with my 5 mm pitch ballscrews gives me a effective range of -1280 to +1280 mm. I need a distance of 0 to 1000 mm on my machine. On startup of LCNC, my encoder reports the correct absolute position of my axis. I have setup the homing sequence as follows:

To the issue: Let's say on startup I am at some random position e.g. 833 mm. LCNC now requires me to press the home button before I am able to switch to teleop mode or issue MDI commands. What happens now, is that the position of the axis is set to 0 and my two soft limits of 0 mm and 1000 mm are applied. This however is in my opinion not correct since the soft limits are now actually at 833 mm and 1833mm. This would lead to a crash if I were to move the axis. I need the homing sequence to keep the 833 mm absolute position value and apply the soft limits at the effective 0 mm and 1000 mm. Basically I need it to just set the "homed" flag and be done with it.

Hope I was able to describe issue somewhat clearly. Any ideas?

Thank you and greetings

Thank you Aciera!

I just changed the settings to these random values:

Now it works as intended and my absolute position persists through the homing process (not set to zero anymore). But no idea why...

[edit]

Alright I have found it. It was a simple spelling mistake in the HOME_ABSOLUTE_ENCODER = 2 line. This led to the setting not beeing applied. Nothing to do with the other lines. In fact I can delete anything about homing besides the absolute encoder setting = 2. Feel really stupid now

Yes correct these are the only lines I have kept. I have set HOME_SEQUENCE = -1 for now so I am forced to home at startup in order to get the soft limits active. This way I will not move the axes by accident without limits in place. Later I plan to automate it so I don't need to press the button anymore.

For anyone copying and pasting - typo in absolute
Should be

Hello Sandro,
would like to talk to you about your configuration of the Lichuan Servos with absolute encoder with linuxcnc.
I need feedback coz i am about to pull the trigger on some kits like that.

Thank you in advance,
Tiago Monteiro from Portugal