[FR] Configuration for robot with syringe pump

[DerAndere1]

Description

As an example, provide documentation on how to set up a robot with 3 axes for positioning and a stepper that drives a syringe pump should be configured.

Additional Information

• Include a ZIP file containing your Configuration.h and Configuration_adv.h files.
• Provide pictures or links to videos that clearly demonstrate the issue.
• See How Can I Contribute for additional guidelines.

[DerAndere1]

Support for additional axes is now part of official MarlinFirmware/Marlin bugfix-2.0.x. An example config and pin file for a machine with 3 cartesian axes for positioning and a stepper that drives a tool such as a syringe pump can be found here: https://github.com/DerAndere1/Marlin/tree/Marlin2ForPipetBot/config/examples/DerAndere1/PipetBot-A8. You can compare the file https://github.com/DerAndere1/Marlin/blob/Marlin2ForPipetBot/Marlin/src/pins/sanguino/pins_DERANDERE_PB_1.h with the file https://github.com/DerAndere1/Marlin/blob/Marlin2ForPipetBot/Marlin/src/pins/sanguino/pins_ANET_10.h to see what has to be changed for an additional axis (I axis). If you want to drive syringe pums with a stepper motor, I recommend not to use an extruder "axis" for that purpose at all. I recommend setting #define LINEAR_AXES 4, #define AXIS4_NAME 'A' and #define EXTRUDERS 0. G1 syntax for movement then becomes G1 X10 Y20 Z30 A40 where parameter A specifies how much the stepper that drives the tool will move