Migration

Migrating from Marlin4MPMD 1.2.2

There are a number of changes from the previous version that are worth noting. Here are some changes worth noting:

1. By default the towers are rotated 120deg to the right to correctly map +Y opposite the LCD screen and and +X to the right of the LCD screen. This was done because the stock mapping makes understanding the mesh leveling grid very difficult. This is functionally the same as swapping the cables. If you've already done this mod, you can undo the software fix by issuing M665 X-120 Y-120 Z-120. It should be noted that this change will likely invalidate your previous mesh grid, as well as the other delta settings. If you are unsure which tower is now X/Y/Z, you can test this easily by setting M666 X-20 Y0 Z0 and noting which tower moves down 20mm after homing.
2. Settings are now stored in flash instead of on the SD card. To load your old settings, just run M32 M_CFG.G followed by M500. If you get an error about the API version not matching this indicates the data in flash isn't valid and should be overwritten. These values can possibly be overwritten when re-flashing the firmware, so you should manually record your settings by M503 before flashing.
3. Higher speed feedrates are now possible as a result of fixing an artificial limit in software. As a result you may find that your retraction and travel settings may need adjustment.
4. Mesh grids are now automatically adjusted so that the center point is always 0.0. The entire grid is adjusted by the center value to ensure that the value is zero. This means that the Z offset adjustment is handled entirely by M665 H. You can either tweak these values by changing the probe offset with M851 Z<offset> and issuing G29 P0 or editing M665 H directly. Increasing H will lower the Z height, decreasing H will raise the Z height. Changes are immediate so the proper procedure is to lower the nozzle until it is just barely above the bed, and then changing M665 H until M114 reports Z=0

Migrating from stock firmware

Some of these changes have been documented in the calibration and Frequently Asked Questions but it's worth collecting here.

1. By default the towers are rotated 120deg to the right to correctly map +Y opposite the LCD screen and and +X to the right of the LCD screen. This was done because the stock mapping makes understanding the mesh leveling grid very difficult. This is functionally the same as swapping the cables. If you've already done this mod, you can undo the software fix by issuing M665 X-120 Y-120 Z-120. It should be noted that this change will likely invalidate your previous mesh grid, as well as the other delta settings. If you are unsure which tower is now X/Y/Z, you can test this easily by setting M666 X-20 Y0 Z0 and noting which tower moves down 20mm after homing.
2. Settings are stored in flash, but cannot be imported from the stock firmware. Most settings are directly comparable to the stock firmware, so you should note them down with M503 before flashing Marlin4MPMD. Notably the PID settings are not directly comparable as the units do not match.
3. Mesh bed leveling is handled differently than the stock firmware. The general strategy is to do a very detailed mesh bed leveling probe one time, save it to EEPROM, adjust as needed, and then re-use the same values from that point on. G29 should be replaced in your start g-code with G29 P0 so that it does a single point height probe instead. If you need to adjust the Z offset, you should change the M851 Z<offset> value and save it to EEPROM. Setting M851 Z-1 is functionally equivalent to G29 Z1. By adopting this method you can keep all start g-code printer independent.
4. All settings are correctly saved to EEPROM so it is unnecessary to put your M92 and M665 settings in your g-code files
5. Depending on the hardware revision of your printer you may need to adjust the M92 steps/mm settings accordingly. Later printers shipping with V43 firmware or greater have stepper drivers with 16x micro-stepping while the earlier printers shipping V37 or V41 firmware have 8x micro-stepping drivers. The M92 values should be set accordingly, however, issuing G29 P0 should detect misconfigured M92 settings and correct them. To avoid this issue, download the appropriate _V43+ .bin files if your printer has 16x micro-stepping drivers.
6. The stock 5A power supply cannot provide enough current to power both bed and hot-end heaters at the same time. As such, the software limits the duty cycle of the bed heater to prevent overdriving the power supply. This limitation is removed in the _10A firmware .bin files, but should only be used with a compatible 10A power supply. Running the wrong firmware will result in the printer rebooting unexpectedly or limiting the maximum bed temperature.