Delta printer, homing issue

Hi everyone.
I need some help regarding the homing of a 3d delta printer, and it's my first attempt to create a 3d printer by scrap.
My problem is regarding the homing, when I do the homing 2 out of 3 endstop work properly but 1(always one) doesn't work properly(see video).
While the support is hitting the endstop, it moves a little back like the others, but then move up again and doesn't stop 'til I do it manually.
there is someone that have some idea to solve the issue? Hope everything is clear enough, otherwise ask me
Thank you in advance.

[youtu.be] <----- video

Edited 1 time(s). Last edit at 11/06/2018 03:44PM by Martinpoles.

Quote
Martinpoles
Hi everyone.
I need some help regarding the homing of a 3d delta printer, and it's my first attempt to create a 3d printer by scrap.
My problem is regarding the homing, when I do the homing 2 out of 3 endstop work properly but 1(always one) doesn't work properly(see video).
While the support is hitting the endstop, it moves a little back like the others, but then move up again and doesn't stop 'til I do it manually.
there is someone that have some idea to solve the issue? Hope everything is clear enough, otherwise ask me
Thank you in advance.

[youtu.be] <----- video

The switch isn't registering, or it isn't configured correctly. so the motor doesn't stop. There is a safer way to troubleshoot this this than banging the end stops.

Before we can really help, we need to know what you are using in your printer. There are a few flavors of controller firmware out there but seems the two biggest are Marlin and Repetier. I speak Marlin pretty well, so that is what I'll talk about.

Let's start with seeing what you do have by learning some gcode. (https://reprap.org/wiki/G-code)
The first thing you need to do is find out what is working. Look up the gcode M119 (Get Endstop Status).
Plug in your printer and start whatever software that you have that gives you a command line interface. I use either Pronterface or Simplify3D which both allow command line connections and have a display for what is returned.

Make sure none of your switches is depressed.
Type in M119 and hit send. If you are running Marlin firmware on your printer you will see the X, Y and Z switch status displayed.
There are two possible responses, "open" and "triggered".
If any of your switches says "triggered", then...
-that switch is miswired
-that switch is configured wrong in firmware
-that switch is broken or there is a problem on your controller board.
The first two are the most likely.

Hold each of your other switches closed and issue the M119 command to make sure that they trigger when they should. If any of them refuse to change state, then you have a wiring problem or a board electronics problem. If you depress the X end stop and Z says triggered, you know what that means.
Go through and find any incorrectly wired or located switches first. If they are all in the correct place and change state when depressed, then your wiring is good, but your configuration is incorrect.

Now we do firmware. You will need the Arduino environment installed to change firmware, so go look up how to do that, and get it all set up. Lots of places on the 'net will have that info. Once you are ready, go to the next step...

Configure configuration.h in your Marlin firmware folder. (Like I said, I only speak Marlin, if you have Repetier, hunt down where the configuration file is for it on the 'web.

In a recent version of Marlin, in the Configuration.h file you will find this block of code:

// Mechanical endstop with COM to ground and NC to Signal uses "false" here (most common setup).
#define X_MIN_ENDSTOP_INVERTING true  // set to true to invert the logic of the endstop.
#define Y_MIN_ENDSTOP_INVERTING true  // set to true to invert the logic of the endstop.
#define Z_MIN_ENDSTOP_INVERTING true  // set to true to invert the logic of the endstop.
#define X_MAX_ENDSTOP_INVERTING false // set to true to invert the logic of the endstop.
#define Y_MAX_ENDSTOP_INVERTING false // set to true to invert the logic of the endstop.
#define Z_MAX_ENDSTOP_INVERTING false // set to true to invert the logic of the endstop.
#define Z_MIN_PROBE_ENDSTOP_INVERTING true  // set to true to invert the logic of the probe.

If your end stops say "open" when pressed and "triggered" when not pressed they they are inverted compared to what you want. On any end stop that acts in reverse of what is expected, switch the corresponding setting above. (NOTE: Z_MIN and Z_MIN_PROBE are normally set to the same values.)
example:
if your Z tower's home does the opposite of what you want, and your Configuration.h file looks like the code above, change the Z_MIN_ENDSTOP_INVERTING to false.
Normally all of your end stops will have the same polarity, but, "stuff" happens, and you can configure the problem away. Then compile and download your corrected source.

NOTE: Make sure that your towers are correctly configured! You won't get anything good if you have the X and Y towers swapped with respect to what your code wants!

So, this should help you find and fix your end stop problem. If you are new to building delta printers. You will get the opportunity to read a whole lot about the topic to familiarize yourself with how they operate. A single question on this forum will not get you there!

Have fun,
DLC

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Kits: Folgertech Kossel 2020 upgraded E3Dv6, Anet A8 upgraded E3Dv6, Tevo Tarantula enhanced parts and dual-head, TronXY X5SA Pro(E3DHemera).
Scratch: Large bed Cartesian, exchangeable heads, Linear slide Delta, Maker-Beam XL Micro Delta, 220x220CoreXY.