Layer tracking with variable layer heights

Phaedrux

@tmreith said in Layer tracking with variable layer heights:

However DWC seems to be calculating layers from a perceived Z height and layer heights.

Yes this may be the case.

What version of firmware and DWC are you running?

tmreith

@phaedrux
Board: Duet 3 MB6HC (MB6HC)
DSF Version: 3.3.0
Firmware: RepRapFirmware for Duet 3 MB6HC 3.3 (2021-06-15)
Duet Web Control 3.3.0

I thought there was a keyword like "layer count" or "num_layers" that was being read in past before DWC would try to calculate based on a layer_height value and the max Z value.

The mixed layer heights are definitely messing with the layer calculation.

I have full control over the gcode, so I can add in the required commented value to drive the DWC.

Phaedrux

Can you update to 3.4.1?

tmreith

@phaedrux
unfortunately not. The machines are validated to 3.3 and would require a re-validation effort if I updated the firmware.

Is there a layer count keyword that is still being used in the g-code? I can insert what ever DWC needs to establish a value vs trying to calculate from a Z height and the layer height value.

Phaedrux

See if you can add num_layers=## to the end of the file.

https://forum.duet3d.com/topic/27471/num_layers-in-g-code/4?_=1662052426372

tmreith

@phaedrux
I added the following to the end of the gcode file, and there was no effect.

; num_layers=64

I looked at the source code for FileInfoParser.cpp and it definitely has a routine to parse "num_layers" keyword. I am not sure why the DWC doesn't seem to see the value.

I have another machine running 3.4.1, so I'll give it a try on that machine over the weekend.

tmreith

@tmreith
Works on a Duet 2 Wifi running 3.4.1.

Added the following to the last line in gcode file.

; num_layers: 64

Phaedrux

Maybe a limitation or bug in the DuetPi version?

@chrishamm

chrishamm

@tmreith @Phaedrux Parsing the number of layers (aka num_layers) isn't supported in DSF or RRF v3.3. In order to use this feature you must be on v3.4 or newer.

PS: Until v3.4 RRF/DSF attempt to compute the number of layers from the object height (last absolute G0/G1 Z command in the print file) and the layer height. If you have an extra G1 Z lift command in there, the reported object height and the number of layers are probably wrong.

Phaedrux

@chrishamm said in Layer tracking with variable layer heights:

If you have an extra G1 Z lift command in there, the reported object height and the number of layers are probably wrong.

His end code Z lift has ; E on the line.

chrishamm

@phaedrux It is correctly processed by DSF 3.4.1, I just checked (object height = 11.05mm). The number of layers was not present in the original file but once added that is parsed correctly, too.