lowrider - independent endstop for each motor z


je viens de commencer le lowrider et j’ai du mal à ajuster avec précision les 2 côtés du portail z pour obtenir un travail parfait. Est-il possible de mettre des butées indépendantes sur chaque moteur en Z afin de pouvoir ajuster avec précision et automatiquement l’horizontalité du support

Dual endstops on Z is possible. There isn’t a preconfigured firmware for it.

When I start the machine, I have both ends down all the way. I give each leadscrew a small turn to lift the side. The side falls down again and they are both very close.

Do you have rails, or are you riding on the table?

Does your gantry fall on it’s own weight when not powered?


Je suis également en train de regarder à ça sur ma machine. Peut tu nous faire part de ta configuration (firmware, carte, … etc) ?

Personnellement j’ai une une Rambo 1.4 pour laquelle j’envisage d’utiliser comme toi des endstops indépendants pour chaque axes Z mais pour ma part le réglage se fera en montée. J’utiliser le firmware GRBL donc toute la surface de la machine doit être en coordonnées négatives.

@jeffeb3 How did you managed to say to the firmware that both Z endstops socket on the board were Z-min (in your case) ? I'm planning to do the same thing that you but the opposite way, I want the both endstops to be Z-max.


I don’t have any endstops. When the machine starts square, it will keep itself square.

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I haven’t done it personally, but in configuration_adv.h there is a section for enabling dual z motors and dual z endstops. You’ll need to also change the pin for z2 (something like ymax is a good choice) and then use zmax and ymax for yhe dual endstops.

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@jeffeb3 I can’t do that i’m on GRBL firmware …

but I may have found a solution :

// NOTE: The homing cycle is designed to allow sharing of limit pins, if the axes are not in the same // cycle, but this requires some pin settings changes in cpu_map.h file. For example, the default homing // cycle can share the Z limit pin with either X or Y limit pins, since they are on different cycles. // By sharing a pin, this frees up a precious IO pin for other purposes. In theory, all axes limit pins // may be reduced to one pin, if all axes are homed with seperate cycles, or vice versa, all three axes // on separate pin, but homed in one cycle. Also, it should be noted that the function of hard limits // will not be affected by pin sharing.
or "just" change the pins in cpu_map.h

but thanks for your reply

Thank you for these responses.

I forgot to specify I have MINI RAMBO but there is 6 endstop above so it must work.
On the other hand I am really very beginner: it is parametre from the LCD screen of the CNC or from the computer?

If I make a mistake when I buy the program, can I get back the original version or am not at all entitled to the error?

tu peux accéder aux paramètres dans le fichier du Dossier du firmware que tu peux télécharger ici (télécharger celui qui correspond à la configuration de ta machine) c’est ce fichier dossier que tu dois ensuite “flasher” sur la carte de la CNC en utilisant le logiciel Arduino. Je ne pense pas qu’il soit possible d’accéder à ces fichier depuis la carte de la CNC via l’ordinateur tu dois donc je pense pour chaque modification que tu souhaite apporter au firmware flasher la carte avec la nouvelle version modifié de ton firmware.

Petite suggestion essai de faire le tour du site il y a par ci par là toute les instructions nécessaires pour se débrouiller avec son matériel. J’ai moi même tout appris via ce site et pas mal de recherche sur le coté. Le lien vers “comment flasher sa carte”

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Automatic squaring will drive each motor into its owm endstop. Each motor needs its own driver for each end to be driven independently. When you home Z, it will push each motor towards the endstops. When the first motor hits the endstop, the second will continue until it reaches its endstop. After that, they will always move in lockstep.

With the mini rambo, you have 4 drivers. It’s meant to be used with a 3D printer, so there is an x,y,z, and extruder driver (E0). You can repurpose the E0 as Z2. That will let you then assign an endstop to the Z2 motor.

There is no way to convert the software on the mini rambo back into something you can use. But if you start with the mpcnc mini rambo firmware from Ryan, you can add dual endstop to Z on it.

  1. disable the E0 driver. Set the number of extruders to 0.
  2. Enable dual Z motors. In configuration_adv.h find the dual motor z and enable it.
  3. Enable dual Z endtops. In configuration_adv.h, right there next to dual motor z enable dual endstop z.
  4. Flash the board according to Ryan’s instructions.
  5. Wire the Z2 motor to the E0 port. Wire the Z1 endstop to zmin. Wire the Z2 endstop to zmax. Endstops get wired between (s) and (-). Not to (+).
  6. Check the endstops with “M119” before trying homing, which is “G28 Z”. You might need to go back and change the Z endstop inverting or Z2 endstop inverting in Configuration.h.

That will let you install endstops at the bottom of Z. If you want to home to the top instead, you need to also do this:
7) In Configuration.h, change the Z home dir to +.
8) In Configuration_adv.h, change the Z2 endstop pin to ymax.
9) Wire the Z1 enstop to zmax. Wire the z2 endstop to ymax.

If you ever decide to quit on this process, just flash Ryan’s firmware with no edits. That is basically what is on there now, although it might be a slightly different version. As long as you stay with Ryan’s firmware, there is a small risk that you will change the firmware on the board, without getting it right. If you make a mistake while flashing, it will not have installed anything.

Flashing the board is a worthy skill to have. There are many other options available to you when you can flash a mini rambo.