zprobe without z max endstop

Im working on setting up a zprobe on an ordbot. The probe trigger is a micro switch wired in parallel with the z min end stop. Does this have to be documented somehow in configuration.h. if so, how do I do that? I don't understand the need or purpose for a z max endstop as it relates to the z probe. Do I need to install one on the bot? Thanks!

We do z-probing, because we assume the bed is not exactly even. If it is not even that means without correction the distance bed-extruder for z changes. Now you do z home at some place. What now happens is:
a) bed is deeper then z-min so nothing wild happens
b) bed is at that point higher then z-min, so extruder crashes into bed.

a) is not allowed it would require to go even deeper with autoleveling and you can not go below z-min endstop.

Also you surely want to avoid b) so z-max homing is superior. The only alternative is to do no z homing and always autolevel before each print, but that is wasted time.

And it is no problem to mount the z-min endstop at the top of the same makerslide. I did it with my ordbot:-) It also has an other benefit. You never need to modify switching position. You only change zLength or use the z-calibration menu on the lcd to measure correct length. Once you now the zprobe offset you do not need any after calibration at all.

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Ahh, I think I understand. I am currently using the Z-min endstop circuit for the probe trigger as well as the min endstop. I can move the min endstop to the top of the column where it will function as a Z-max endstop while software will control how low the nozzle will go towards the bed. This allows the extruder to go below "0" to follow the negative contours of the bed. Yes?
Thanks, Rolland. I don't know how you find enough hours in the day to take care of all of us!

I'm afraid I still cannot get z-probe to work on my ordbot. I added a zmax endstop and turned the zmin into the z-probe switch. M119 shows all endstop switches L until tripped. Z home is now against the zmax stop. Homing functions work as they should. Would someone kindly look at my configuration.h file and tell me where I'm going wrong? Thanks!

Problem was an endstop setting, direction issue and too close to it for too long. I'll start a topic for my new problem

Edited 1 time(s). Last edit at 04/01/2014 10:37PM by airkuld.