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Z home pronterface works, G28 Z0 makes Z movement freeze

Posted by HugoW 
Z home pronterface works, G28 Z0 makes Z movement freeze
December 09, 2018 01:16PM
Hi,

with a lot of help on this forum and some tinkering I got my RAMPS 1.4 (24V) with TMC2130 V1.1 stepper drivers and Marlin 1.1.9 working. As sensors work, all axis and the extruder move as they should. Homing X and Y works (no sensorless homing, yet, just micro switches). Z has an inductive sensor, sensing the alumunium plate bed, and that works too.

But I have trouble homing the Z axle when using Marlin:
- When I ask pronterface to home the Z-axle, using the little house button with the Z in it, it works. First a fast sense, then a slow and accurate final sense.
- When I ask Marlin to home the Z-axle, either solo or with all three axis together, via G28 in Pronterface or giving the homing command on the RepRapDiscount full graphic smart controller, it moves away from the sensor a few mm and then freezez. After a while, I get the message "Homing failed" and I need to reset. Trying G29 (I have set it up for 3-point sense) gives the same result. It moves to the first sensing location and then it freezes when the bed wants to approach the sensor.

I cannot figure it out, can you? All help is appreciated.

Cheers,

Hugo
Re: Z home pronterface works, G28 Z0 makes Z movement freeze
December 23, 2018 10:54AM
Well, I've pretty much given up. I hate this. I've tried a gazillion Marlin settings and today I even replaced the TMC 2130 drivers with basic A4988 drivers. Wrote a fresh new Marlin, uploaded, it all worked. And then it started failing again, first a little bit and it is progressively getting worse. Here is what it did earlier this afternoon:

[www.youtube.com]

Now it just freezes when I ask it to home. With Marlin replaced 38945739458 times, all drivers replaced, next on my list is new RAMPS and real (not Chinese copy) Mega. Unless you have any ideas?

Cheers,

Hugo
Re: Z home pronterface works, G28 Z0 makes Z movement freeze
December 23, 2018 12:20PM
Try sending a M119 - End Stop States
It appears that the Z-Axis Sensor is staying triggered, check this using a metal putty knife and the M119 -End Stop States using pronterface .

Edited 1 time(s). Last edit at 12/23/2018 12:28PM by Roberts_Clif.


Electronics Technician / Computer Programmer
Re: Z home pronterface works, G28 Z0 makes Z movement freeze
December 23, 2018 04:27PM
Thanks for the reply. I checked all with M119 and all homing sensors say open and triggered when they should. But just to be sure, I am hooking up a mechanical end switch (identical to the X and Y sensors) tomorrow, to temporarely replace the inductive sensor. If that does not fix it, I am replacing the RAMPS and Mega. I did notice today, while replacing the TMC2130 with A4988, the Z driver came off the board a lot easier than the others (bad contacts??) and the capacitor soldered on the RAMPS underneath the Z driver is positioned slightly off in comparisson to the ones under the other drivers. Weird. The complete sensor set-up worked before with the MKS board I used (which s**ked for other reasons).

Cheers,

Hugo
Re: Z home pronterface works, G28 Z0 makes Z movement freeze
December 24, 2018 05:51AM
Well, I don't get it but I am relatively happy. I replaced the inductive sensor with a micrco-switch, like the switches I have on the X and Y axis. Used all in Marlin with pullups and inverted and it all works. The Z sensor is not in the correct position to actually be usefull, but it works. Both G28 and G29 do what they should. What I don't get is why the unschanged way I hooked up the inductive sensor to the Z now malfunctiones but it didn't on the previous board. Also, M119 gives me proper readings each time. I tried over 50 times with short intervals, like one or two seconds between tries. All M119 readings are correct with the inductive sensor, the way I had it set up. I used a 7805 to cut down the signal voltage, I will now try it with a voltage dividing resistors set-up.

Thanks for pointing me in the right direction,
Cheers,

Hugo
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