G29 S1 command

  • After issuing a G29 in your print G code is it necessary to issue a G29 S1 to load the height map that was just created. I'm running the latest release firmware and it doesnt look like my prints are adjusting to the bed map without issuing a G29 S1. I don't remember having to do this in the past, but this is my first printing using the full X travel.

    On a side note is necessary to open your z limits to allow negative travel for the compensation to run correctly?

  • Should mention I'm using a BL touch.

    I've confirmed the BL touch trigger point is consistent.

  • Moderator

    G29 on its own will run the compensation mapping routine and then apply the results. Running g29 S1 will load an already saved heightmap.

    It shouldn't be necessary to set a negative z minima but it wouldn't hurt anything if you did. It may help when you're trying to find the trigger height, but there's also a seperate command to allow travel beyond the set boundaries that would be more appropriate.

    When you set z0 at the center of the bed when you home that becomes the 0 reference point. When it runs the mapping routine it will find the bed at each point on the bed where it probes and those points will be either below or above the 0 point. As long as your bed can physically travel down to the low points it will compensate for it.

  • Thanks for the quick reply. When running just the G29 it does not seem to be compensating. I paused the print and manually went to 0 and there is a clear gap at the edge where the bed was low.

    I reran the print with the G29 S1 added after the probe sequence and it appeared that the compensation was now running.

    Very odd I'll have to do some more testing. I'll also check the firmware I'm running. I don't recall having any issues when I originally installed the BL touch and I checked that everything was running correctly.

  • Moderator

    You can see if it's active by sending m122 to get a diagnostic report. There will be a line that says bed compensation: mesh if it's active.

  • @phaedrux can I send that mid print or should I manually run the probe then issue the command?

  • Moderator

    You can send it midprint

  • Seems to be working today. Not sure what the deal was.

    Thanks again for the quick response.

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