Endstops on Rambo 1.4

Hello everyone!
The package I received from Ryan included a Rambo 1.4 and 4 limit switches.
I’m not sure how should I connect the stepers and limit switches to the board.
Does the flash that Ryan has already made include the dual endstops or do I have to install them myself?
I just connected the stepers with the split cables that Ryan sent and the limit switches do not respond.

There are two configurations for wiring up your machine often referred to as “serial” and “dual end stop.” You can find the information on wiring up your system on the following links:


Serial wiring is simpler to wire and simpler to setup and does not use the limit switches. There is debate on this forum about the value of dual end stops. A serial setup with hard end stops (squared, physical end stops to push the truck against), can accomplish nearly everything a dual end stop system can…perhaps done using different steps.

As for the firmware, unless something has changed recently, Ryan ships his boards flashed with the serial wiring setup. If you go to a dual end stop setup you will need to reflash your board with dual end stop version.

If this is your first time wiring up something like this, I recommend using the serial wiring. After you have some experience with your machine you can evaluate whether you want dual end stops.


First of all, thanks for your answer,
Do you know what is this thing I see on the lsd>v1 custom settings> home xy - home z?
How the machine makes homing without endstops?

A bit of background before answering your question. Unlike 3D printing, cutting on an MPCNC is almost always relative to the stock. That is the home (0,0,0) position is specified as some point on the stock. The middle top of the stock is common, as is the top of the stock in the lower left corner. You mount your stock at some random position on your spoil board, maneuver the router and the tip of the bit to the position you specified as the home position when you authored the g-code file, and then start your cut. There is no need to home the machine relative to the machine’s origin.

Homing is not necessary to cut anything. Homing of some sort has two major benefits. First it squares the trucks. If one of the stepper motors for a particular axis is further along the belt than another, the cutting will be slightly off. Note this is less of a problem for the Primo than the Burly since there is an adjustment you make in the Primo build that helps keep your rig square. The second benefit of some sort of homing is being able to repeatedly find a specific point on the spoil board. This is useful if you want to repeatedly make the same cut. For example, this week I’m helping my daughter make a cat climbing wall. I am creating a number of open ended boxes with finger joints as corner connections. Using pegs, I can return my material to exactly the same position on my spoil board, and then starting from my home position, I can return my bit to exactly the same XYZ point to start cutting.

So to answer your questions:

How the machine makes homing without endstops?

Again, for most cutting you don’t need homing of the whole machine. But if you want homing without electronic end stops, you would install something that stops the trucks equal distance from the ends at the origin. You could use hose clamsp on the tubing. If you are gentle, you could use the 3D printed stop blocks that are part of the Primo build. Or out on Thingiverse these would work, though their intended use is a bit different. So with physical stops, you would push both axes against their stops before turning the machine on. This establishes a repeatable home position and it squares the trucks.

Do you know what is this thing I see on the lsd>v1 custom settings> home xy - home z?

The home xy starts the “automatic” homing sequence. There is also another menu item that will start the this homing sequence. Note using either of these two menu items will begin moving the router to the origin. On a rig with serial wiring, there are no end stops to stop the homing, so it will just run your rig into the corner until it cannot physically move anymore. The steppers will make some ugly sounds but won’t be hurt, and you will have to shut down your electronics.

Note that home z will work on a serial rig. It just requires you to wire up a touch plate and optionally make a slight change in the firmware to account for the touch plate thickness. Or alternately the z homing can be done from a g-code file. Personally I use a touch plate all the time, but many people just adjust the z height manually either by look or by feel using a piece of paper. A touch plate is optional and can easily be added after you have a bit of experience with your machine.

thanks a lot for your help

Thank you! I have had the issue where I think my board is faulty when I set g92 x0 etc. and then click HOME on Repetier, the thing just runs into the corner (or to some set distance that I cant seem to change) and clicks against the extents of my machine. Thanks to your well thought out explanation, I no longer need to concern myself with the answer because it just seems that ‘it is what it is’. It seems I can just forget the HOME button exists and move on with my life. Now on to drawing stuff!

Forget home for awhile, and have some fun. I’ve only seen one bad board in all the endstop/homing issues I’ve seen on this forum. So if you ever want to tackle getting your endstops working, I’m sure there are people on the forum that can walk you through the steps to troubleshoot your problem. And the one case of a bad board, we found a workaround.

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