MP3DP -- How to set up the endstops

#1

so im fixing my printer up and getting ready to print today and im getting the endstops ready.

i dont have a problem with the x and y axis endstops, mostly my question is about the z axis.

when setting up the z axis endstop. do i have the nozzle on the bed or offset to like lets say 0.2 to start its extrusion or is there a different way to set it up?

and what would i need to change in the firmware or software (repeiter host) for using the endstops and setting it up for (0,0,0)

thanks for the help.

#2

get a cardstock, put it in the bed and the nozzle should be on top of the cardstock You should have enough friction when you move your cardstock from the bed (check some YouTube videos) then adjust your Z axis screw accordingly. In Repetier, send G28 (or AutoHome in your LCD). Ryan’s firmware for MP3DP should be setup with endstops and autohome to 0,0,0

#3

It’s the other way. Z should nozzle just touching the bed. The first move in a sliced file is pick up the nozzle the height of the first layer.

#4

I have a question about the end stop wiring. I wired according to this diagram:
http://reprap.org/mediawiki/images/6/6d/Rampswire14.svg

My end stops and ramps board are from here. I soldered the connections and they are good (the connections not the soldering job).

Anyways my switches are backwards or something. When I try to move in the direction of the end stop via pronterface, it says end stop triggered at Z##.## (current position). I can get movement in both directions when I close the switch by hand.

This is true for all axes.

Is this an issue that can be fixed with pin placement on the board or do I need to resolder the end stops using the middle prong (3)?

#5

Sounds like you have Normally Open (NO) wired instead of Normally Closed (NC). You can switch in the software, but it’s best if you rewire to NC. If you got any documentation with the end stops it should show which is which. They are not always the same. If not just use a meter to verify you have essentially no resistance between the two pins unless you click the switch at which point you see infinite resistance.