Marlin: SINGLENOZZLE does not work

Created on 9 Jun 2018 · 22Comments · Source: MarlinFirmware/Marlin

I am using Marlin 2.0.x/2137 with SINGLENOZZLE setup but it does not seam to work.
Setup: Custom I3\RAMPS 1.4\Cyclops\2 extrudes

When printing something that uses only my second extruder, printer starts printing immediately without heating the nozzle.

GCODE has only statements like M104 S230 T1

Config file:
Configuration.txt

Question

Source

lavato

All 22 comments

You need to check over your slicer setup. I have a dual extruder single nozzle setup and mine works. T1 is Tool number 1 which would translate to the second extruder. Tool 0 is the first.

M104 does not wait for heatup. M109 will wait.

cdedwards on 9 Jun 2018

👍1

I checked and can find M109 - so this must be something else.

See below the gcode snippet, generated by Slic3r:

M190 S80 ; set bed temperature and wait for it to be reached
M104 S238 T1 ; set temperature
;G29 L1
;G29 A
G28
;G29 J
G1 Z5 F5000 ; lift nozzle
M109 S238 T1 ; set temperature and wait for it to be reached
G21 ; set units to millimeters
G90 ; use absolute coordinates
M82 ; use absolute distances for extrusion
G92 E0

etc.

The only time this works is if you have a statement like: "M104 S238", without T1
If you specify T1, like "M104 S238 T1", the hot end does not heat up.

This is tagged incorrectly, in my opinion, as this is a bug.

lavato on 10 Jun 2018

you are correct, this is a bug. M109 T1 S238 is not doing anything. something in M109 T1 is causing this command to return immediately instead of setting temp and then waiting. In fact, looking at the logic of this, I feel it's wrong. In SINGLENOZZLE mode, we don't care which extruder is active or not. we have a hotend, fed by two extruder motors. heat up the hotend.
I believe that your host is set for active tool 0 and you are attempting to heat tool 1. This will cause Marlin to return immediately

cdedwards on 10 Jun 2018

The T parameter to M104/M109 is not the "tool" index, but the hotend index. If there's only 1 hotend, then M109 T1 has nothing to do.

thinkyhead on 11 Jun 2018

so if this is a hotend index. how do we specify a extruder motor. I need to be able to switch between two motors not two hotends.

cdedwards on 11 Jun 2018

when I tell simplify3d to switch to my other extruder, it sends a T[number] command to switch. Selecting another tool index will cause this as well

cdedwards on 11 Jun 2018

As far as I understand, when you are in SINGLENOZZLE mode, the printer should ignore any M109/M104 that specifies a T other than the currently active tool.

A normal tool change from cura looks something like this:
T1
M104 T0 S190
M109 S220

M104 T0 S190 should be ignored, as the previous T1 command sets tool 1 active.

Note that I am not 100% sure on this, so correct me if I'm wrong :)

skasti on 11 Jun 2018

As far as I understand, when you are in SINGLENOZZLE mode, the printer should ignore any M109/M104 that specifies a T other than the currently active tool.

Just reviewing the code now, it appears you are correct!

void GcodeSuite::M109() {

  if (get_target_extruder_from_command()) return; // Return if < 0 or >= EXTRUDERS
  if (DEBUGGING(DRYRUN)) return;

  #if ENABLED(SINGLENOZZLE)
    if (target_extruder != active_extruder) return;
  #endif
  . . .

thinkyhead on 12 Jun 2018

and therein lies the problem. in a single nozzle system, do not ignore a heatup command. We should not care what hotend is specified by the T command as we only have one. We are using the T command in our case to set a extruder motor instead of a hotend, so what does it matter if the target_extruder != active_extruder.

cdedwards on 12 Jun 2018

I'm not sure why it's always been this way. The original coder must have had some justification. I'll see if I can track them down and find out why.

thinkyhead on 13 Jun 2018

I understand why it is this way: When changing extruder part-way through a print, the G-code sequence is this:

G92 E0
G22
T1
G92 E0
G23
M109 S220
M104 T0 S190

If you don't ignore the M104 T0 190, you will cool the hotend and get a clog

When starting a print, this is the cura-generated G-code for heating up:

T0
M190 S60
M104 S200
M104 T1 S175
M109 S200
M109 T1 S175

For this g-code to work as intended, the M104 and M109 that specify T1 (T0 was selected earlier) must be ignored, or you will only heat hotend to 175 degrees, and you will not be able to print.

skasti on 13 Jun 2018

👍1

@cdedwards
Yes you are correct, the active tool is 0.

BTW - for some reason github.com was complacently inaccessible for me for couple of days!?!

@thinkyhead
Yes, but Slicers do not have a knowledge if you use single nozzle or not - so they will always generate code as if you have 2 hotends

lavato on 14 Jun 2018

Is the issue that the slicer is trying to turn off or cool down the inactive hotend between tool-changes?
Is there a setting in your slicer that will simply leave the hotend(s) alone between tool-changes, instead of trying to cool down the inactive one?
By now slicers should understand that there is such a thing as SINGLENOZZLE and change their behavior taking this into account.

thinkyhead on 14 Jun 2018

@thinkyhead

1) No
2) This is not an issue.
3) Actually, I am split on this.

Marlin in the SINGLENOZZLE config, should understand that it has to activate the only hotend it has, when it executes e.g. M104/9 S238 T1 (corrected T1 only).

Currently it only works if the gcode has no T at the end of M104/9 S238.

If not fixed, when in SINGLENOZZLE mode and using only the second extruder, Marlin air prints.
I.e. Printer prints nothing, however the gantry moves and the hot end temp target is 0.

In my case the workaround is to manually edit the gcode and remove all references to T1.

lavato on 15 Jun 2018

the hot end temp target is 0.

How does the target temperature get set to 0? An M104/M109 that targets a non-existent hot-end should just exit without changing the target temperature.

thinkyhead on 15 Jun 2018

When M104\9 S238 T1 is executed it seems never to be set at anything.

The way I see it, when using extruder 2 only (T1) - Slic3r gcode unchanged:

M190 S80 ;         >>>>>>>>EXECUTED
M104 S238 T1 ;  >>>>>>>>IGNORED
G1 Z5 F5000 ; >>>>>>>>EXECUTED
M109 S238 T1 ; >>>>>>>>IGNORED
G92 E0 >>>>>>>>EXECUTED
etc

When using extruder 1 (T0) -manually added T0 to gcode, as when using T0 only, Slic3r removes T0 :

M190 S80 ;         >>>>>>>>EXECUTED
M104 S238 ;  >>>>>>>>EXECUTED
G1 Z5 F5000 ; >>>>>>>>EXECUTED
M109 S238 ; >>>>>>>>EXECUTED
G92 E0 >>>>>>>>EXECUTED
etc

When using extruder 1 (T0) - Slic3r gcode unchanged

M190 S80 ;         >>>>>>>>EXECUTED
M104 S238 ;  >>>>>>>>EXECUTED
G1 Z5 F5000 ; >>>>>>>>EXECUTED
M109 S238 ; >>>>>>>>EXECUTED
G92 E0 >>>>>>>>EXECUTED
etc

lavato on 15 Jun 2018

The way I see it, when using extruder 2 only (T1) - Slic3r gcode unchanged:

If the command T1 were sent first, then everything would work.

thinkyhead on 15 Jun 2018

If the command T1 were sent first, then everything would work.

Not sure what the question or the statement means?
T1 is sent first?
Do you mean if I reverse execution on below, what would happen?

M190 S80 ;         >>>>>>>>EXECUTED
M104 S238 T1 ;  >>>>>>>>IGNORED

Also, as above, can this be re-tagged, to reflect that this is a bug?

lavato on 16 Jun 2018

Do you mean if I reverse execution on below…?

No, I mean, if T1 was ahead of the commands…

T1
M190 S80
M104 S238 T1

thinkyhead on 30 Jun 2018

@lavato problem solved in bugfix 2.0?

boelle on 20 Feb 2019

To elaborate on this being closed, SINGLENOZZLE got quite a bit of attention around the holidays so its pretty much a totally different animal at this point...