3.2.2 RC1 firmware for Prusa i3 MK2/S/MMU

This firmware for MK2/S contains important safety improvement in preheat error and also chosen features from MK3S branch.

Summary:

• Preheat error improved
• Improved temperature regulation
• Remaining time estimation
• Adjustable beeper notifications
• Incomplete file check updated
• G-code fixes (M27, M110, M115)

Detailed description of changes:

Preheat error improved:

On older firmware version there was a zone where preheat error was not working properly. If thermistor would be damaged during the preheating phase in a particular way (resistance of damaged thermistor would be in the range corresponding to the measured temperature > 150 °C), preheat error was not triggered.
Improved preheat error now works in full range. MK2/S implementation also contains update which should prevent false bed preheat error occurrence.

Improved temperature regulation:

When changing temperatures during the print, temperature regulation was very slow in some cases. Regulation has been improved.

Remaining time estimation:

The current firmware version is ready to display remaining time estimation and accurate progress on printer status screen. Information about remaining time will be counted by Slic3r and inserted into G-code file. Gcode M73 is used for this. In this case, the letter 'R' is shown next to print time to indicate that it is remaining time estimation. For speed factor different than 100 %, time estimation may not be accurate, which is then indicated by the letter '?'. In case that there are no M73 G-codes in a file, printer behaves as in previous release versions, i.e. showing time from the print start. The status screen was slightly modified because of this feature. Symbol "SD" is now shown on printer status screen only during active SD print (i.e. not in idle state) together with progress in percentage. When printing over USB, there is a "USB" symbol shown together with progress in percentage.

It is possible to turn on/off estimated print time support in Slic3r by switching to expert mode and clicking on "Supports remaining time" check-box in Slic3r Printer Settings -> General. In future versions of Slic3r settings,

Adjustable beeper notifications:

In Prusa MK3S/MK2.5S firmware there are different levels of the acoustic signalization (since 3.4.0 firmware version). This feature has been ported to MK2/S firmware. User is able to choose between each level in the printer's menu -> Settings –> Sound. You can also change the sound settings during the print in the menu -> Tune.

Level description:
Loud - printer uses acoustic signalization for a failure or if confirmation is needed
Once - this level is similar to Loud, but all beeps are played only once.
Silent - most of the beeps are muted, the user is informed only in case of a serious error

Mute option (all beeps muted, used in MK3S/MK2.5S printers from 3.4.0 release) has been excluded for safety reasons.

Incomplete file check updated:

Last firmware 3.1.0 for MK2/S can falsely report that printed G-code file is incomplete. This was happening typically with G-code files generated in new Prusa Slic3r versions. This has been fixed.

G-code fixes:

G-codes which are used to report printer status (M27), machine type and firmware version (M115) and to set line number (M110) when printing remotely (for example using Octoprint) have been fixed.

Other:

• Translation correction
• Stop print fix

3.7.0 Firmware for MK3, MK3S, MK2.5 and MK2.5S

Detailed description of changes (compared to 3.7.0-RC1):

7x7 mesh bed levelling:

There was a possibility of X-axis crash on the first mesh bed levelling point (issue #1674). This has been fixed.
Improved mesh bed levelling (3.7.0-RC1) uses shorter Z movements to reduce overall calibration time. This in some cases leads to "Enforced Z-leveling" occurrence (issue #1651) triggered by higher variability in measured Z-values, which was probably caused by mechanical resonance. In current FW version, if Z-values variability is too high for certain measured point, there is a short delay and then current point measurement is repeated with longer Z-movements (the same measurement algorithm which was used on FW 3.6.0 and all older versions).

Duplicate T-code fix:

Fixes issue #1660

3.7.0-RC1 Firmware for MK3, MK3S, MK2.5 and MK2.5S

Summary:

• 7x7 mesh bed levelling
• MMU2S fast mode (MK3S + MMU2 only)
• Improved T-code load (printers with MMU2)
• Change filament fix (printers with MMU2)
• Eject filament contains ramming (MMU2 printers)
• The informative message during switching between normal and stealth modes
• Improved behaviour when removing SD card
• Autoload disabled in extruder info (MK3) and sensor info (MK3S) menu

Detailed description of changes:

7x7 mesh bed levelling:

It is now possible to increase mesh bed levelling XY resolution by activating measuring 49 points in 7x7 mesh. This can be done in the menu "Settings -> Mesh bed levelling". There is also a possibility to change the number of measurements for each point from 1 (fast, but less accurate) to 5 (most accurate) and also turn on/off magnet compensation. PINDA probe Z-coordinate measurement can be influenced by heatbed magnet proximity (by approximately 80 um) and thus distort mesh bed levelling calibration. If magnet compensation is off, all 49 points are measured and used for mesh bed levelling correction. If magnet compensation is on, for chosen points (which may be affected by magnets) are counted from surrounding points. Also, the mesh bed levelling Z-measurement algorithm was slightly modified to make the whole process faster. No G-code modification is needed. Standard G80 G-code will behave according to settings which were set in "Settings -> Mesh bed levelling" menu. It is also possible to use G80 Nx Ry G-code, where x is a number of mesh bed levelling points in one axis (3 or 7 are valid values) and y is number of Z-measurements for each point (which are then averaged). Settings done directly in G-code has higher priority then settings which are set in the menu.
I would like to thank all who were working on this feature and helped to implement it to our Prusa FW, especially @stahlfabrik, @mionut and @3d-gussner.

MMU2S fast mode:

On MK3S printers with MMU2 connected it is possible to switch MMU between fast and stealth mode. Fast mode can save about 5 seconds per filament change, which can speed up especially long prints with frequent filament changes. MMU fast mode should be considered experimental feature for now. For highest reliability we currently recommend MMU stealth mode. Switching between MMU modes can be done in the menu "Settings -> MMU mode". With MK2.5S MMU runs always in stealth mode.

Improved T-code load:

Load sequence was slightly modified to reduce missing layer error count.

Change filament fix:

When changing filament (M600 G-code, menu "Tune-> Change filament" or filament runout) on printers with MMU2 connected, there is a possibility to re-do filament unload and load by choosing "Filament not loaded". This, however, didn't work properly in some scenarios and filament could remain stuck between extruder Bondtech pulley and nozzle. This has been fixed.

Improved behaviour when removing the SD card:

When SD card is inserted SD card menu is automatically shown. When SD card is removed menu which was active when the SD card was inserted is restored.

Autoload disabled in extruder info (MK3) and sensor info (MK3S) menu:

These menus serve for checking if the filament sensor works properly. The filament can be now inserted (without triggering load function) to check if sensor state changes.

3.6.0 Firmware for Prusa i3 MK3/MK3S and MK2.5/MK2.5S

This is final version of 3.6.0 firmware. In this firmware version feature "smarter load/unload/eject" has been improved (comapred to 3.6.0-RC1) to work properly in all currently known scenarios.

Summary:

• Initial version for MK3S and MK2.5S printers with MMU2 unit
• Smarter load to nozzle/unload/eject function for multi material printers and single material version improved
• Stop print during filament change fixed

For detailed description of all changes, please check 3.6.0-RC1 change log.

3.6.0-RC1 Firmware for Prusa i3 MK3/MK3S and MK2.5/MK2.5S

Summary:

• Initial version for MK3S and MK2.5S printers with MMU2 unit
• Smarter load to nozzle/unload/eject function for multi material printers and single material version improved
• Stop print during filament change fixed

Detailed description of changes:

Smarter load to nozzle/unload/eject function for multi material printers and single material version improved:

This feature has been recently added to firmware in 3.5.2-RC1 version, but this initial version has been working only for single material printers (without MMU2 connected). In this firmware version, it has been extended to provide similar function also for multi material printers. We also decided to change function slightly to make it more useful for most users. When a user chooses to load filament (for example) with the cold nozzle for example, preheat menu appears and both nozzle and heatbed are preheated (to save some time later when starting a print) and printer waits for the nozzle to preheat close to the target temperature (5% below target). When preheating is finished, printer beeps and the user can start loading filament. Target temperature remains the same after the load is finished as we assume that most load/unload scenarios precede starting new print.

Stop print during filament change fixed:

When stopping print during the T-code execution nozzle could crash into wiping tower. This has been fixed.

3.5.3 Firmware for Prusa i3 MK3S and MK2.5S

This is initial fw version for MK3S and MK2.5S printers. It contains all features from 3.5.2 firmware plus bed level correction range was enlarged to +-100 um. This firmware version is recommended only for single material printers (without MMU2 connected) and should not be used with standard MK3 and MK2.5 printers.

3.5.2 Firmware for Prusa i3 MK3 and MK2.5

This is final version of 3.5.2 Firmware. Only difference compared to 3.5.2-RC1 are new messages translations and language corrections. For detailed description of all changes, please check 3.5.2-RC1 change log.

3.5.2-RC1 Firmware for Prusa i3 MK3 and MK2.5

Summary:

• More quiet print fan operation
• Heatbed regulation improved
• Improved heater temperature regulation
• Spool join for multi-material prints
• Smarter load/unload function
• Mintemp for MK2.5 updated
• SD card menu is shown automatically when the card is inserted
• Safer communication between MMU2 and printer
• Crash detection for zero target temperature fixed

Detailed description of changes:

More quiet print fan operation:

This change is significant especially for low fan speeds.

Heatbed regulation improved:

Heatbed PWM now works on a higher frequency. This helps to reduce the power supplies "clicking" noises.

Improved heater temperature regulation:

When changing temperatures during the print, temperature regulation was very slow in some cases led to preheat error. Regulation has been improved. This should solve issue #1362.

SpoolJoin for multi-material prints:

It is now possible to use the "SpoolJoin" function also with multi-material prints. If some filament is depleted, the printer replaces it with next filament for the rest of print (for example if filament 2 was depleted, the printer starts using filament 3 instead). If there is no filament which can be used (all filaments were depleted), the printer waits for the user to insert new filament manually.

Smarter load/unload function:

If a user chooses load (or unload) in the menu with a cold nozzle, nozzle preheat menu automatically appears. After selecting material, preheat starts. When the nozzle is hot and the printer is ready for a load, beeper signal occurs. This function is working on single material printers with load/autoload and unload. It is not currently implemented for multi-material printers (load to nozzle, unload and eject).

Mintemp for MK2.5 updated:

"Mintemp" is now checked after a short period of preheating. This is necessary for maximum reliability on all MK2.5 Rambo boards.

3.5.1 Firmware for Prusa i3 MK3 and MK2.5

Summary:

• Button click fix
• M220 speed factor
• Z-levelling fix (MK3)
• Pause print -> stop print fix

Detailed description of changes:

Button click fix:

The function for button press evaluation and debouncing was modified in previous firmware version to make the code more accessible for the future. However, this code improvement introduced a bug which could cause that some fullscreen messages which waited for the user to press the button were skipped. This has been fixed.

M220 speed factor:

On multi-material printers, speed factor is currently set to 100 % before filament change by Slic3r PE. This ensures that filament change will proceed with defined speed and thus higher reliability.
There is now a possibility to save and restore speed factor on MK2.5 and MK3 printers using the following G-codes:
M220 Sxxx sets speed factor
M220 B sets backups current speed factor
M220 Sxxx B sets speed factor and backups current speed factor
M220 R restore saved speed factor
These M-codes are the same as on MK2 printers with Firmware 3.1.0 and allows Slic3r PE to backup speed factor set by the user (by rotating the knob on the printer) before filament change and then to restore is when filament change if finished. This will fix issues #1364 and #1208.

Z-levelling fix (MK3):

Z-levelling function introduced in previous Firmware 3.5.0 could repeatedly fail (X-axis staying at the top with a message "Some problem encountered, Z-leveling enforced ...") on MK3 printers under certain conditions. This has been fixed.

Pause print -> stop print fix

Stopping paused print could lead to behaviour when some movements were missing during new print or first layer calibration. This has been fixed.

3.5.0 Firmware for Prusa i3 MK3 and MK2.5

This firmware version was focused on finalization of features from previous 3.5.0-RC1 firmware version. For the detailed description of all features and improvements please check also 3.5.0-RC1 change log.
New Slic3r settings which will contain new Tx and Tc codes used in single mode (for printers with MMU2) will be released soon.

Summary of changes (compared to 3.5.0-RC1):

• Z-levelling fix
• M500 - M503 fix
• FINDA dependency on optical sensor fixed
• Translation corrected
• Progress bar display during M600 fixed
• Pause print communication timeouts fixed

Detailed description of changes (compared to 3.5.0-RC1):

Z-levelling fix:

A feature called "Mesh bed levelling fail triggers Z-levelling" was added in previous firmware version. However, there was one bug which caused that after Z-levelling coordinates were shifted in Z. This has been fixed.

FINDA dependency on optical sensor fixed (printers with MMU2):

In the previous firmware version, we have improved FINDA independency on the optical filament sensor. However, there was still a scenario where FINDA was disabled in case that optical sensor was damaged or disconnected. This has been fixed.

M500 - M503 fix:

In previous firmware version, we have improved functions for storing settings to EEPROM and restoring them (M500 - M503) to provide improved reliability in the future and prevent issues which we had encountered in 3.4.0 firmware. Now we have fixed initialization of new variables, which were added to M500 recently. If you have encountered some issues with slow Z-axis movements in 3.5.0-RC1 version, please upgrade to 3.5.0. Otherwise, there is no change from the user's point of view.