Motion Command has invalid target

I’m using Vcarve with the post processor created on this forums for that softare and the latest CM. It keeps throwing this error at me: “Motion Command has invalid target”. totally random. Any file with a lot of arcs will get this error but running the same program from two different files produces this same error at two different places.

I found this but its a fix for fusion which i wasn’t using.

Anyone know how to fix this?

Let’s see if @neilferreri has something to say about possibly applying the same fix in the VCarve post, as was applied in the Fusion360 post.

As a temporary workaround, since this is is related to rounding errors, you may want to try switching between inches and mm post-processors, whichever you were using, see if that helps. It definitely won’t be a definitive cure, but could help getting those files to work. Easy enough to try anyway.

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Id love to use a metric Post Processor but I’ve only found one in inches for V carve.

The one found here.

Exactly which post processor are you using?

Carbide3D-Nomad-Inch.pp

Try one of the Grbl ones here:

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Thanks I’ll try it in in and metric and report back.

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Hey Simon/Alexander.

I made this one for my Nomad and VCarve. It’s metric, and I’ve used it without issue for well over a year. It also works perfectly on a Shapeoko.

VCarve-Carbide3D-Nomad-mm.zip (507 Bytes)

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@Gerry Anything new I should add to the ones in the GitHub repo?

Hey Neil,

It actually has less in it, I think. It’s based on the 10.5 Grbl_mm post processor and lets that do most of the work. It’s very short but I haven’t had any issues at all with it:

POST_NAME = "Carbide3D Nomad mm (*.nc)"

POST_BASE = "Grbl_mm.pp"

FILE_EXTENSION = "nc"

UNITS = "MM"

LINE_ENDING = "[13][10]"

+
+    Formatting for variables
+

LINE_NUMBER_START     = 1
LINE_NUMBER_INCREMENT = 1
LINE_NUMBER_MAXIMUM = 9999999

VAR LINE_NUMBER = [N|A|N|1.0]
VAR SPINDLE_SPEED = [S|A|S|1.0]
VAR FEED_RATE = [F|A|F|1.1]
VAR X_POSITION = [X|A|X|1.4]
VAR Y_POSITION = [Y|A|Y|1.4]
VAR Z_POSITION = [Z|A|Z|1.4]
VAR ARC_CENTRE_I_INC_POSITION = [I|A|I|1.4]
VAR ARC_CENTRE_J_INC_POSITION = [J|A|J|1.4]

begin HEADER

"%"
"G17"
"G21"
"G90"
"M6 T[T]"
"M3 [S]"

begin TOOLCHANGE

"M6 T[T]"

begin NEW_SEGMENT

"M3 [S]"

begin FOOTER

"M5"
"M30"

It’s a derivative of the others with the things that were already in Grbl_mm removed.

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It works in ok metric (even though it was programed in inch). Thank You

Yup, the machine will move the right distance regardless of the post processor unit.

The simple post processor isn’t anywhere near optimal… it doesn’t support arc efficiently.

My original posting supports arcs and tool changes. I explained what need to be changed G20 → G21. Then rename things appropriately.

If people want it, I’ll work up an optimal post processor.

mark

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The posts on my gitHub repo linked above handle arcs and toolchanges (and dwell commands and rapid plunges). I’m always open to suggestions as apparently Vectric is sending people these post processors.

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For reference for your post-processor, arc support is in Grbl_mm.pp, which is included in the simple post processor.