First cut success - with questions!

Nightowl

So how do I do this with the spindle control? Will adding just the M3 command run the spindle at the same 'saved' speed? I'm not too clear on that!

As it's a CNC machine I would prefer to raise the Z axis to 5mm below its maximum height on Pause, so how would I counteract that in the Resume?

engikeneer

@nightowl999 yes it will use the last set spindle speed if no S parameter is given (according to the docs at least...). I don't have a CNC to test it on though

Nightowl

Thanks again, @engikeneer

These are my proposed changes (except for the Z height, which I'll experiment with!), and I'll check if they work tomorrow.

; pause.g
M5 ; stop the spindle
G91 ; relative positioning
G1 Z5 F360 ; lift Z by 5mm
G90 ; absolute positioning
G1 X0 Y0 F2400 ; go to X=0 Y=0

; resume.g
G1 R1 X0 Y0 Z5 F2400 ; go to 5mm above position of the last print move
G1 R1 X0 Y0 Z0 ; go back to the last print move
M3 : turn the spindle on

Thanks again

dc42

@nightowl999 said in First cut success - with questions!:

So how do I do this with the spindle control? Will adding just the M3 command run the spindle at the same 'saved' speed? I'm not too clear on that!

I have to admit that I hadn't given any thought to restoring spindle speeds on resume. Spindle speeds are not saved in the restore point that is created when you execute a pause. However, I think you can achieve it like this. Caution: I have not tested this!

In config.g add this

global savedSpindleSpeed = 0

In pause.g after the G1 Z move (see later) add this:

if currentTool >= 0 & tools[state.currentTool].spindle >= 0
  set global.savedSpindleSpeed = tools[state.currentTool].spindleRpm  ; save the current spindle RPM
  M5   ; turn spindle off

In resume.g (before the final move to the original position, if you have one):

if currentTool >= 0 & tools[state.currentTool].spindle >= 0
  M3 S{global.savedSpindleSpeed}
  G4 S1  ; wait 1 second to allow the spindle to spin up

As it's a CNC machine I would prefer to raise the Z axis to 5mm below its maximum height on Pause, so how would I counteract that in the Resume?

Change these lines in pause.g:

G91 ; relative positioning
G1 Z5 F360 ; lift Z by 5mm
G90 ; absolute positioning

to:

G1 Z{max(move.axes[2].userPosition+5,move.axes[2].max-5}

In resume.g you probably want to change this line:

G1 R1 X0 Y0 Z5 F2400 ; go to 5mm above position of the last print move

to:

G1 R1 X0 Y0 F2400 ; go to above the paused XY position, keeping the current Z

OwenD

@Nightowl999
There's a closing brace for the max() function missing on this line
G1 Z{max(move.axes[2].userPosition+5,move.axes[2].max-5}
should be

G1 Z{max(move.axes[2].userPosition+5,move.axes[2].max-5)}

Nightowl

You guys are pretty damn good at this!

Thank you @dc42, @OwenD and @engikeneer. I'll make the changes/updates tomorrow and let you know how I get on, as this might be of use to others!

Thanks again

Edit: Am I correct in thinking the M5 and M3 commands are where you've put them (i.e. last and first, so the cutter in the spindle will cut the material rather than snap, as a safety precaution? Obviously it would be better not to hit anything at all, but just in case...!

Also, is indenting of line of code important?

It's late, but this is how I've interpreted your suggestions (without the description text but including the original, obsolete lines REM's out):

; pause.g
; M5
; G91
; G1 Z5 F360
; G90
G1 Z{max(move.axes[2].userPosition+5,move.axes[2].max-5)}
; G1 X0 Y0 F2400
if currentTool >= 0 & tools[state.currentTool].spindle >= 0
set global.savedSpindleSpeed = tools[state.currentTool].spindleRpm
M5

; resume.g
; G1 R1 X0 Y0 Z5 F2400
if currentTool >= 0 & tools[state.currentTool].spindle >= 0
M3 S{global.savedSpindleSpeed}
G4 S1
G1 R1 X0 Y0 F2400
; G1 R1 X0 Y0 Z0
; M3

o_lampe

@nightowl999 said in First cut success - with questions!:

G1 Z{max(move.axes[2].userPosition+5,move.axes[2].max-5)}

To me it looks like there is a little problem with this line...what if the userPosition is already higher than (max-5)? Would it try to move +5 anyways and hit the upper limit or stop automatically at max?
Either way, it would be best to test this scenario to see if it returns to the right hight after resume

//sidenote: for further reference it would be best to move this thread to either Meta commands or CNC section (IMHO)

Nightowl

That's a bit worrying, @o_lampe, but I'm no code writer.

@o_lampe said in First cut success - with questions!:

To me it looks like there is a little problem with this line...what if the userPosition is already higher than (max-5)? Would it try to move +5 anyways and hit the upper limit or stop automatically at max?

My logical mind makes me think that line moves the Z axis up 5mm from it's current position, then moves to the maximum Z height less 5mm. I'm assuming the [2] refers to the "3rd" axis (e.g. X would be [0], Y [1] and Z [2])?

If that is the case, would only the following be needed to move the Z axis 5mm below the Z max:

G1 Z{max(move.axes[2].max-5)}

Could I enter that as a command line to test it?

Thank you

dc42

@o_lampe said in First cut success - with questions!:

To me it looks like there is a little problem with this line...what if the userPosition is already higher than (max-5)? Would it try to move +5 anyways and hit the upper limit or stop automatically at max?

The move would be limited to max Z.

Nightowl

I guess you've answered my question, thank you @dc42!

Nightowl

Implementing those changes has caused a different problem, I can't run any g-code files.

The console is reporting the following error:
M32 "0:/gcodes/Initial Test Cut.nc"
File 0:/gcodes/Initial Test Cut.nc selected for printing
Cancelled printing file 0:/gcodes/Initial Test Cut.nc, print time was 0h 0m
Error: G0/G1: target position outside machine limits

I've REM'd out the global variable in config.g, but that didn't make any difference. Does it matter where this is located within the config.g file? I've put it after General Preferences.

I can't get far enough to test the pause.g or resume.g files.

dc42

@nightowl999 which firmware version are you using? If you are using recent firmware that supports the 'global' command then I think you must have made another change at the same time. The position of that command in config.g is not critical, but I suggest near the end.

Nightowl

This has become rather perplexing...

Yesterday I could run a couple of test cuts without any problem. In fact, I was really pleased!

After implementing the changes above (although I didn't check the machine before I made those changes today!) the files won't run, reporting the error:

M32 "0:/gcodes/Initial Test Cut.nc"
File 0:/gcodes/Initial Test Cut.nc selected for printing
Cancelled printing file 0:/gcodes/Initial Test Cut.nc, print time was 0h 0m
Error: G0/G1: target position outside machine limits

So I reverted to the original pause.g and resume.g files and REM'd out the global command, but I still get the same issue.

I have had the outside machine limits error before, when trying to sort the axes and limit switches out, but that got resolved.

Nightowl

@dc42

Board: Duet 3 MB6HC (MB6HC)
Firmware: RepRapFirmware for Duet 3 MB6HC 3.3 (2021-06-15)

Which is a bit weird, because I keep copies of the version upgrades (in case I need to go back) and the version I have in storage is 3.4

Nightowl

@dc42

Just updated the firmware, but there's no difference.

I guess I'll start from scratch and go through the RRF config tool again.

Ho hum

jay_s_uk

@nightowl999 why? its obvious whats going on. you're trying to run a job outside the axis limits. redoing the config won't change that

fcwilt

@nightowl999 said in First cut success - with questions!:

I guess I'll start from scratch and go through the RRF config tool again.

IMHO the RRF config tool is a barrier to learning the g-code that controls your machine.

The issue of trying to move past the axis limits is simple. However you generated the code it was using axis limits that did not match your machine.

How do you generate code for a CNC machine?

Thanks.

Frederick

Nightowl

@jay_s_uk

@jay_s_uk said in First cut success - with questions!:

@nightowl999 why? its obvious whats going on. you're trying to run a job outside the axis limits. redoing the config won't change that

I guess I must be, but redoing the config (or at least looking at my original config to compare with the existing one) was the only place I felt I could reliably start from, but there is little difference between the two files.

jay_s_uk

@nightowl999 exactly, little difference so is a pointless task.
What are your M208 limits?
Are you using workplace offsets?
How big is the part?
What coordinates is the part at in the CAM software?
Are you working with 0 as the top of the stock or the top of the spoil board?

Nightowl

@fcwilt

@fcwilt said in First cut success - with questions!:

The issue of trying to move past the axis limits is simple. However you generated the code it was using axis limits that did not match your machine.
How do you generate code for a CNC machine?

Yesterday I was using Vectric Cut2D Trial version to cut their 'Avalon' sample file and ran it successfully, but this was before I made any of the changes shown above.

I made the file changes today and then used Vectric Cut2D Desktop version (I've just bought the license) to run a small test file, and get the error.

I've homed the machine after turning it on, moved the gantry to - and set - the work zero and loaded the file, then I got the error. IO am able to jog the machine in any of the 6 directions away from the work zero, and the machine goes back to that spot when I click Home All, but again the file won't run.

What have I missed?