Pressure advance tuning with conditional G-code

[oozeBot]

Here is the console output. This was tested on a 6HC with attached SBC running 3.4b5.

After simulation:

M37 P"0:/gcodes/1636019653286-pa.g"
Error: Operation failed (Reason: ArgumentException in SimpleCode: Cannot convert Z parameter to float (value {var.layer_height}))

After upload:

Failed to get file info for 1636019653286-pa.g
Operation failed (Reason: ArgumentException in GetFileInfo: Cannot convert Z parameter to float (value {var.layer_height}))

[Heartleander81]

Am I correct that the SBC scans the file and since it does not find a clear layer height, the error is there? Is only a guess, since without sbc the error is apparently not there

The test run now at my printer with the 2 error line 139 and 141. Nice work.

[Schmart]

@heartleander81 said in Pressure advance tuning with conditional G-code:

Am I correct that the SBC scans the file and since it does not find a clear layer height, the error is there? Is only a guess, since without sbc the error is apparently not there

Well, it does indeed seem the handling is different compared to running the G-code on a standalone board. Please run the following macro, first with M37 and then with M98. Make sure you've homed the Z-axis yourself, and/or adjust the macro to suit your printer.

var z = 25.0
G1 Z{var.z} F600

I think that if this small snippet fails, we should follow up with one of the developers.

I've also run the code posted by @PCR on my printer as well, with M37, M32 and M98. The only thing that was noticeably different, were some printer-specific adjustments he made, and lines ending with \x0A\x0A (LFLF) characters, while mine uses \x0D\x0A (CRLF). So this code should run fine.

The test run now at my printer with the 2 error line 139 and 141. Nice work.

So you're still seeing the weird 'purge_139_flow_ratio' and 'purge_141_flow_ratio' errors? These kind of errors are triggered when a variable is not defined. I can't explain the cause of that. But it seems that the word 'line' in the variable name purge_line_flow_ratio gets substituted with the named constant called 'line' in the firmware part that prepares macro error messages. That also shouldn't happen.

I can't reproduce this with my firmware build, and I haven't yet tested with an older firmware. Can you check what the following macro yields?

G1 X{var.a_line_liner} F600

On my printer this results in the following expected error message. It doesn't say unknown variable 'a_1_liner' or unknown variable 'a_1_1r' or something like that:

Furthermore, can you run the macro(s) without the SBC (don't know if that's possible with your setup) and/or share what M122 returns?

[Schmart]

@heartleander81 About variables and this script running on a SBC, the documentation does still state that "These are supported in RRF 3.3 running in standalone mode". I'm not sure if this still applies, but it might explain your problems.

[Schmart]

@izeman said in Pressure advance tuning with conditional G-code:

I wanted to try the code as well, and it doesn't seem to work as expected. The nozzle and bed heat up, and then the heater is turned off again as it starts printing it seems.

I came across this fix in the release notes for RepRapFirmware 3.4.0beta3:

M568 did not allow the P parameter to be omitted

So that explains that!

[izeman]

@schmart said in Pressure advance tuning with conditional G-code:

@izeman I'm missing text like 'Axes to be homed' in the console, so I'm assuming you had to modify the code for the topology of your printer.

Yes. Thanks. I inserted my G32 & G29 S1. All axes are homed.
And I now just have to correct the M568 command, as I'm running 3.3 still. And then we'll see

[Heartleander81]

@schmart

That come when I make a macro with: G1 X{var.a_line_liner} F600.

My M122

=== Diagnostics === 
RepRapFirmware for Duet 3 MB6HC version 3.4.0beta5 (2021-10-12 13:53:56) running on Duet 3 MB6HC v1.01 or later (SBC mode) 
Board ID: 08DJM-9P63L-DJ3T8-6J1DA-3SD6P-KV4H9 
Used output buffers: 1 of 40 (14 max) 
=== RTOS === 
Static ram: 151104 
Dynamic ram: 66408 of which 240 recycled 
Never used RAM 132920, free system stack 200 words 
Tasks: SBC(resourceWait:,0.6%,518) HEAT(notifyWait,0.0%,321) Move(notifyWait,0.0%,351) CanReceiv(notifyWait,0.0%,772) CanSender(notifyWait,0.0%,374) CanClock(delaying,0.0%,339) TMC(notifyWait,8.2%,92) MAIN(running,91.0%,921) 
IDLE(ready,0.2%,30), total 100.0% 
Owned mutexes: HTTP(MAIN) 
=== Platform === 
Last reset 00:09:14 ago, cause: software 
Last software reset at 2021-11-05 11:27, reason: User, GCodes spinning, available RAM 127336, slot 0 
Software reset code 0x0003 HFSR 0x00000000 CFSR 0x00000000 ICSR 0x0043c000 BFAR 0x00000000 SP 0x00000000 Task SBC Freestk 0 n/a 
Error status: 0x00 
Aux0 errors 0,0,0 
Step timer max interval 134 
MCU temperature: min 30.8, current 32.7, max 43.3 
Supply voltage: min 25.1, current 25.2, max 25.2, under voltage events: 0, over voltage events: 0, power good: yes 
12V rail voltage: min 12.1, current 12.1, max 12.2, under voltage events: 0 
Heap OK, handles allocated/used 0/0, heap memory allocated/used/recyclable 0/0/0, gc cycles 0 Driver 0: pos 0, standstill, SG min/max 0/0, reads 8042, writes 14 timeouts 0 
Driver 1: pos 0, standstill, SG min/max 0/0, reads 8041, writes 15 timeouts 0 
Driver 2: pos 0, standstill, SG min/max 0/0, reads 8041, writes 15 timeouts 0 
Driver 3: pos 0, standstill, SG min/max 0/0, reads 8042, writes 14 timeouts 0 
Driver 4: pos 0, standstill, SG min/max 0/0, reads 8042, writes 14 timeouts 0 
Driver 5: pos 0, standstill, SG min/max 0/0, reads 8045, writes 11 timeouts 0 
Date/time: 2021-11-05 11:37:02 Slowest loop: 24.87ms; fastest: 0.04ms 
=== Storage === 
Free file entries: 10 
SD card 0 not detected, interface speed: 37.5MBytes/sec 
SD card longest read time 0.0ms, write time 0.0ms, max retries 0 
=== Move === 
DMs created 125, segments created 0, maxWait 0ms, bed compensation in use: none, comp offset 0.000 
=== MainDDARing === 
Scheduled moves 0, completed 0, hiccups 0, stepErrors 0, LaErrors 0, Underruns [0, 0, 0], CDDA state -1 
=== AuxDDARing === 
Scheduled moves 0, completed 0, hiccups 0, stepErrors 0, LaErrors 0, Underruns [0, 0, 0], CDDA state -1 
=== Heat === 
Bed heaters = 0 6 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1, chamberHeaters = -1 -1 -1 -1 
=== GCodes === 
Segments left: 0 
Movement lock held by null 
HTTP* is doing "M122" in state(s) 0 
Telnet is idle in state(s) 0 
File is idle in state(s) 0 
USB is idle in state(s) 0 
Aux is idle in state(s) 0 
Trigger* is idle in state(s) 0 
Queue is idle in state(s) 0 
LCD is idle in state(s) 0 
SBC is idle in state(s) 0 
Daemon is idle in state(s) 0 
Aux2 is idle in state(s) 0 
Autopause is idle in state(s) 0 
Code queue is empty 
=== CAN === 
Messages queued 4978, received 11016, lost 0, longest wait 2ms for reply type 6049, peak Tx sync delay 5611, free buffers 49 (min 48), ts 2772/2771/0 Tx timeouts 0,0,0,0,0,0 
=== SBC interface === 
State: 4, failed transfers: 0, checksum errors: 0 
Last transfer: 2ms ago 
RX/TX seq numbers: 21916/21916 
SPI underruns 0, overruns 0 
Disconnects: 0, timeouts: 0, IAP RAM available 0x2b7dc 
Buffer RX/TX: 0/0-0 
=== Duet Control Server === 
Duet Control Server v3.4-b5 
Code buffer space: 4096 
Configured SPI speed: 8000000Hz 
Full transfers per second: 39.68, max wait times: 45.1ms/18.9ms 
Codes per second: 0.15 
Maximum length of RX/TX data transfers: 3040/832

[medicusdkfz]

Hi,

thank you for your incredible job... Could you tell me, what the latest version is?

TY, Pierre

[PCR]

@medicusdkfz still the first one. Which is working perfectly here

[CNCModeller]

@schmart

This seems to be working a treat on my machine. Thanks very much for the effort!

The only tweaks I did was to:

• Move the position of the print as I can't print in the centre of my bed, and alter the basic print settings.

• Add a var to control if the file was simulated or not in a single location. I then put an if before the relevant GCode statements w.r.t. setting and un setting simulation mode.

; Single location to activate simulation mode
var sim_mode = 0

if {var.sim_mode > 0}
   M37 S1 ; Enter simulation mode

if {var.sim_mode > 0}
   M37 S0 ; Leave simulation mode

Disable Bed heating if the temperature is set to 0 as I don't have a working heated bed yet.

if {var.bed_temperature > 0}
   M190 S{var.bed_temperature} ; Wait for bed temperature to reach setpoint

if {var.bed_temperature > 0}
   M140 S0 ; Turn off bed

Just thinking a similar approach to retraction / de-retraction distances might be a nice project too, albeit I'm going to have to learn a lot about conditional GCode to figure that out!!

Anyway thanks again, this is great

Best Regards
Barry M

[Schmart]

@heartleander81 that little one-liner you ran (error message pun intended) confirmed that variables in the meta command language are not yet (fully) supported on SBC setups. Unfortunately, my macro heavily relies on variables and I don't see a simple alternative to avoid using them. I think your best chance is to ask one of the RRF developers for an outlook on support for SBC-based setups.

[Schmart]

@medicusdkfz said in Pressure advance tuning with conditional G-code:

Hi,

thank you for your incredible job... Could you tell me, what the latest version is?

TY, Pierre

Thanks Pierre! And yes, the macro in the first post is still the latest version. I'm planning to provide an update with minor changes this week, including the ones from @CNCModeller, but probably nothing drastic. If you have any ideas for improvement, let me know.

[Schmart]

@cncmodeller said in Pressure advance tuning with conditional G-code:

This seems to be working a treat on my machine. Thanks very much for the effort!

You're welcome, I'm happy that you got it working

• Add a var to control if the file was simulated or not in a single location. I then put an if before the relevant GCode statements w.r.t. setting and un setting simulation mode.

I've since learned that M37 also supports simulating a macro based on meta commands, and that doesn't require changing the code itself, so that might even be a more robust option for a less confident user?

On the other hand, your approach 1) puts the code itself in "debugging mode" which is persistent and developer-friendly and 2) doesn't add the "time taken" at the bottom of the macro file.

Disable Bed heating if the temperature is set to 0 as I don't have a working heated bed yet.

That's an excellent point, I hadn't considered printers without a heated bed. If you don't mind, I would like to incorporate your optimizations.

Just thinking a similar approach to retraction / de-retraction distances might be a nice project too, albeit I'm going to have to learn a lot about conditional GCode to figure that out!!

The reason why I found the pressure advance tuning such a good first use case, is because I couldn't convince my slicer to print a contiguous perimeter/wall with different speeds. At least in PrusaSlicer, the modifiers insisted on splitting the model in separate parts.

However, I was also a bit proud and hand-crafted all G-code and calculations myself, with secondary features like the brim taking a disproportional amount of time. So I wouldn't necessarily recommend doing that.

I'm currently tackling retraction tuning with PrusaSlicer entirely. I simply add two cylinder shapes some distance apart, and enter a height-based formula in the "Before layer change G-code" text box in PrusaSlicer that determines the retraction value.

Theoretically, such a test model would not be difficult to convert to a macro. However, I'm dearly missing the concept of a 'function' in the meta command instruction set, which would make it easier to create and maintain such code. Therefore, I think the quickest road to success is to further resist the urge to DIY things like infill and circular perimeters and start by parameterizing the G-code of a pre-sliced model.

Do you have any favorite models to tune retraction?

Anyway thanks again, this is great

[CNCModeller]

@schmart feel free to use anything I've contributed.

I'm only just getting to the point of wanting to dial in my printer by science rather than guessing / witchcraft. Print quality and speed has only just got good enough to warrant the effort.

I believe Teaching Tech's calibration website is a pretty good resource. But I used your code before venturing over there.

link

Personally I was thinking the same way as you, two decent diameter thin wall towers and judge stringing and wall gaps on un-retract when starting a layer on each tower.

Definitely something I need to get to grips with!

Thanks again

All the best.
Barry M

[CNCModeller]

@schmart

PS: w.r.t functions, I think it's possible to call other gcode files as subroutines and I even think you can pass in variables in recent beta firmware but not sure about returning results. More reading required lol.

[T3P3Tony]

@cncmodeller, @Schmart you would need to use a global variable, set in the sub macro, to pass information back to the main calling macro.

[Schmart]

@t3p3tony said in Pressure advance tuning with conditional G-code:

@cncmodeller, @Schmart you would need to use a global variable, set in the sub macro, to pass information back to the main calling macro.

Hi Tony, I had already done some testing with moving subroutine code in separate macros. On the surface, it seems that, between the Neanderthal approach of copying and pasting code, and re-using logic through parameterized macros, the balance tips towards the latter. However, I came across some conceptual and technical downsides that made me decide otherwise:

• Abstraction. I consider the macro as a vehicle for an end-user, not a developer; a cohesive unit of code that an end user would want to run. The macro is the 'public interface' to the functionality provided. A 'submacro' should not be able to have a public interface since it doesn't provide a useful experience by itself.
• Coupling and reliability. Subroutines exist to improve the maintainability of code and are not intended for an end-user to touch or run. If a unit of code is spread across multiple macros, it's easy for the end user to break functionality (e.g. remove a macro) or never get the functionality to run (e.g. not naming macros correctly). The absolute locations and names of macros are suddenly important and tightly coupled to the whole solution.
• Deployment and versioning. Depending on the complexity of the test print I want to generate, there could be many submacros involved, for things like circles, infill, fonts, etc. Splitting a solution in (potentially) many different macros complicates the setup, handling and publishing of code and updates. This becomes even more challenging when the same submacro is used by multiple main macros and the submacro needs an update that maintains backward compatibility.
• Testability. When using submacros, I have even less troubleshooting options and I can't isolate problems in my code properly. The only surefire way to test a multi-macro solution is to actually execute it with M98 and send it to the printer. The developer experience is therefore not optimal:
  1. If I call the main macro with M37 P"parent", the M98 P"child" within the main macro (with the purpose of calling the submacro) is not executed. Submacros are only called when I execute the main macro with M98.
  2. If I send an M37 S1 command in the DWC console, this causes any echo statement to be suppressed, leaving me fully in the dark. Using M37 S1 in the main macro is an option, but then submacros are still not called.
  3. Isolated testing of a 'submacro' is not possible since M37 doesn't accept parameters. Wrapping that submacro with another macro is of no use because of point #1.
• Scope. Traditionally, variables in a parent's scope are available to a subroutine, function, a C++ preprocessor directive or a code fragment that's simply #included from another file. However, variables in a parent macro cannot be shared with a child macro, and that makes sense in terms of separation of concerns. Ways to solve this:
  • Making all or only the necessary variables global is an option, though, to avoid naming clashes, these should be namespaced properly. However, I consider this a workaround. I believe the concept of global variables is more suited to defining a small number of shared and relatively static or read-only printer settings. Global variables don't really seem intended for inter-scope communication where there are a lot of global variables in use and where they continually change.
  • Using parameterized macros is also an option. However, because of parameter naming requirements, the number of variables that can be passed to a macro is limited. You can use single letters only, and three or four letters are already reserved (G, M, N and T). Additionally, this requires me to convert back and forth between highly recognizable local variable names and obscure macro parameter names, and keep the mapping between these logical.
• Performance. I haven't yet determined if the speed with which macros can be called would be an issue, so whether e.g. caching of called macros is implemented. For sections of a print that need to be executed quickly and frequently, this would be a requirement to prevent stuttering in the movement and blobs in the print. Accuracy and timing is pretty important in test prints, so that's something I need to avoid.

All in all, I've settled on putting the code as one big chunk in a single macro for now, and my hopes for the future are that some of the remarks above can be addressed!

---

I've included the test code. I had to slightly clean up the code to include it in this post.

Hopefully that provides some additional clarification to the above epistle (TLDR anyone? ).

_Parent code

Run this with M37 P"0:/macros/_Parent". Note how messages from the child macro are not included. Running this with M98 P"0:/macros/_Parent" does call the child macro, but also actually tries to print this. Wrapping the parent code between M37 S1 and M37 S0 commands and running it with M98 also ignores the call to the child macro. At least on my RepRapFirmware 3.4.0 beta 6.

echo "Parent started"

while {iterations < 10}
  echo "Calling child macro, iteration #" ^ {iterations}
  M98 P"0:/macros/_Child" X50 Y50 F2400 R6000

echo "Parent ended"

_Child code

Note that a standalone simulation with M37 P"0:/macros/_Child" X100 Y100 F2400 R6000 does not work because M37 does not pass parameters, and causes unknown parameter errors.

var size_x = {param.X}
var size_y = {param.Y}
var feedrate = {param.F}
var travel_feedrate = {param.R}

echo "Child started"

; Print single-perimeter rectangle
G90 ; Use absolute coordinates
G1 X{-var.size_x / 2} Y{-var.size_y / 2} F{var.travel_feedrate}
G91 ; Use relative coordinates
G1 X{var.size_x} F{var.feedrate}
G1 Y{var.size_y} F{var.feedrate}
G1 X{-var.size_x} F{var.feedrate}
G1 Y{-var.size_y} F{var.feedrate}

echo "Child ended"

[Schmart]

@cncmodeller said in Pressure advance tuning with conditional G-code:

@schmart feel free to use anything I've contributed.

Thanks! I took the liberty of integrating your suggestions.

Personally I was thinking the same way as you, two decent diameter thin wall towers and judge stringing and wall gaps on un-retract when starting a layer on each tower.

I came across this site which seems to offer an interesting approach to retraction tuning as well. For now, I hacked together a more classical attempt to tune retraction settings . Please see attached file Retraction.g.

I tested this on my printer, but still, please consider this a beta release.

[CNCModeller]

@schmart said in Pressure advance tuning with conditional G-code:

@cncmodeller said in Pressure advance tuning with conditional G-code:

@schmart feel free to use anything I've contributed.

Thanks! I took the liberty of integrating your suggestions.

Personally I was thinking the same way as you, two decent diameter thin wall towers and judge stringing and wall gaps on un-retract when starting a layer on each tower.

I came across this site which seems to offer an interesting approach to retraction tuning as well. For now, I hacked together a more classical attempt to tune retraction settings . Please see attached file Retraction.g.

I tested this on my printer, but still, please consider this a beta release.

@Schmart That's brilliant and it works fine on my machine.

I have added restart length variation as follows so you can run it twice once with zero restart increment to identify optimum retraction, then a second time with a good retraction length start value and zero retraction increment and a restart increment to get the optimum restart length.

See code changes below.

; Retraction restart length to start with
var retraction_restart_length_start = 0.0
; Retraction restart length increment for each (whole) millimeter print height
; e.g. if var.height = 20, var.retraction_length_start = 0.0 and var.retraction_length_increment = 0.05,
; then the retraction test range is from 0.0 to (0.0 + 20 * 0.05) => 0.0 to 1.0.
var retraction_restart_length_increment = 0.05

; Set firmware retraction
M207 S{var.retraction_length_start} R{var.retraction_restart_length_start} F{60 * var.retraction_speed} T{60 * var.deretraction_speed} Z{var.retraction_z_lift}

  ; Set firmware retraction
  var retraction_length = {var.retraction_length_start + var.z * var.retraction_length_increment}
  var retraction_restart_length = {var.retraction_restart_length_start + var.z * var.retraction_restart_length_increment}
  M207 S{var.retraction_length} R{var.retraction_restart_length} F{60 * var.retraction_speed} T{60 * var.deretraction_speed} Z{var.retraction_z_lift}

  ; Output some statistics while printing
  echo "Layer " ^ {var.layer} ^ " (" ^ {var.layer + 1} ^ " of " ^ {var.layers} ^ " at " ^ {var.z} ^ "mm)"
  echo "Retraction length: " ^ {var.retraction_length}
  echo "Retraction Restart length: " ^ {var.retraction_restart_length}

From memory that's all I changed. I can post my full file but it has my customisations for print settings and location.

Many thanks again!!

Cheers
Barry M

[PCR]

@cncmodeller could you post the full file?