I power on the printer for the first time and set up the Limit Switches, Axis Movement, End Stops, Bed Extents, Bed Levelling, Z Probe/Bed Sensor and do the Extruder Calibration!
I spent quite some time going through the Marlin documentation to see what each possible configuration instruction could do. I had already done a very basic run through of the Configuration.h file in this video/post but now it was time to get it spot on.
One side benefit of the exercise is that I can see I will need to change the way I mount the heated bed. Most importantly the nyloc nuts sitting on top reduce the Y axis extents by nearly 25%!!!!. But secondly the ply wood under the bed allows the nuts to squash the edges down too much, resulting in the opposite bed bend to that I had before! Still, good enough for a first print 😉
As I am not sure yet exactly where the RAMPS will end up, I am just going to wire everything long and hook it all up temporarily to get the printer up and running. I will revisit the wiring once everything is working and tidy it all up. But this is good enough for now!
I cover a few little things that I needed to look up, pin outs etc. The rest was an easy job… so long as you have the right crimps to hand!!!
If you have a Z probe that needs more than 5v to operate, then you can run it directly from the 12v supply and run the signal wire (usually black) through a voltage divider and from there into the RAMP Z Min Endstop connector.
The values for the voltage divider are R1=10kOhm and R2= 6.8kOhm. This will drop the 12v to 4.9 and result in a power loss of only 85mW.
I didn’t end up needing to do this – although the probe was spec’d for 6-36 Volts (if I remember correctly) it worked fine with just 5v.