Smoothieware for a Prusa i3 Mk2 clone - endstops and probe

Controllers Smoothie
1

Hi,

I’m starting build planning for a DIY clone of a prusa i3 mk2. I want to keep my build as close as possible to the stock setup, but I want to build as much as possible myself and improve on what I can.

I haven’t bought any electronics for it yet. The stock i3 mk 2 uses rambo, and I’d really rather go a bit more modern that than so I am quite interested in getting a smoothieboard.

I’ve been reading up on smoothieboard and smoothieware and I’m still a little confused about endstops and probes.

From smoothieware’s point of view, as documented in the wiki (can’t link to the page) , a z probe is not and cannot be an endstop. I kind of get that from an ideological point of view and I realise that that purity is necessary for good quality and universal code in smoothieware.

However, in reality it’s not true. Several printer designs and other firmwares are quite capable of using a z-probe in place of a Z endstop and the prusa i3 mk2 is an example of this. The prusa i3 mk2 does not have a hardware z end stop and relies entirely on the z probe for that.

Is there any way to support a printer like this with smoothie? Or, if I do decide to use smoothie for my build, will I *have* to modify the printer to add a physical end stop?

Kind regards

Jon

Imported from wikidot

2

The wiki is just telling this because many users install a zprobe and then expect it to *behave* like an endstops, and get very confused when it doesn’t. That’s all.

But you can install a zprobe and *use it* like an endstop.

Simply use G30 ( seek a zprobe ) instead of G28 Z0 ( seek an endstop ) to home your Z, it’s that simple.

3

thanks arthur. a further question:-

if i did fit an end stop, and used mesh bed levelling with a probe, I don’t really understand how the interact. If, for example, with an end stop, you do G28 Z, which sets a 0 reference for z when the microswitch is triggered, what happens in terms of smoothie logic if the mesh bed levelling finds a set of points which are all >0 ?

Or is it down to me to ensure that the Z probe offset is set such that the mesh points are distributed above and below Z=0?

hard to ask what i’m asking, i can’t phrase it very well!

4

You need to set your z height, yes. Read the bottom of the zprobe page it shows several methods to do so.

I want to say : you shouldn’t be worrying about this before you try it out. Simply wire your machine, read the documentation, do what it says, and you will understand a lot of things simply by doing them.

5

ok, thanks for your help!