Disabling Z axis and strange behaving Y axis (solved)

Hey

Im trying to build a laser printer so obviously I dont need Z axis. I uploaded repetier on gen7 electronics and after some tinkering I have proper XY movements. Ive set the Z axis to zero.


there are two problems.

When X is homing everything is ok!

When Y is homing it makes the home routine ok and then goes to the far end of the board instead of sitting on homing

The second strange effect is when I am on manual control. X and Y behave normally. But when I press the Z axis movement instead of nothing, the Y axis starts moving (and never stops).


is there something I have missed??

thanks in advance

Edited 1 time(s). Last edit at 10/29/2015 04:05PM by waste.

The firmware was not really designed to have no z axis. Connecting no motor and having no endstops is ok. You still should give it steps and height also it is not changeable. Especially if autoleveling is enabled it might try moving z. Except that case which makes no sense in your case I see no reason why z moves should influence the y axis at all. But i smight depend on your zero solution. Zero is often evil it it gets used in divisions.

I'm currently working on making a laser mode for the firmware. Current plan is having M3/M5 for laser (like GRBL does it) or alternatively a increasing E value for moves (so we can use slicers instead). Hope to cut some papers next weekend with it:-)

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great work for the laser part . I was using M106 M107 the fan control to control the laser as many people here do

I think you are right with zeros , I changed the Z axis to 1 for good measure. I actually managed to make X axis behave properly, but Y is giving me much pain

it homes alright, but after it homes it moves back to Y max position while the M114 command says something like
18:25:45.816 : X:23.00 Y:-52428368.00 Z:1.00 E:0.00

and when I manually move it 10mm it goes back to home position -10mm.

And I dont know if this is connected but Y axis doesnt want to do small steps (1mm or 0.1mm) even though it does big ones 10mm or 50mm


I tried changing stepper motor , stepstick, microstepping (from 1/16th to 1/8th) and position on the board (from physical Y to physical Z) but it behaves exactly the same.

do you have any ideas??

Could it be a serial cable problem? I tried to change baudrate to 28800 and the Y axis behaves normally for some time now .

It homes and stays there, and also makes 1mm steps.

You would see it in the log if you have a com problem. WIth gen7 you never know and you also have to watch out with 16/20mhz and compiling accordingly. But if it homes there is no reason to go there. You can not say it in home command. YOu might enable echo to see what firmware gets and executes if in doubt.

After homing it should move
#define ENDSTOP_Y_BACK_ON_HOME 1
to the right, I guess it's not set to -52428368.00?

M106/107 have the problem of being not in sync with moves, so you have to add a wait before every change. That's why I do not like it for laser/cnc and want a better solution.

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Yep you are right Gen7 are usually a little bit "home made" (mine at least it is). Its the one and only I made (I got another one from traumflug). Then the chinese RAMPS got so cheap it didnt make much sense to make and troubleshoot your own.

The strange behaviour was going back to normal after unplugging pluggin the usbttl. I dropped the Serial speed to 9600 and it behaved normally for more time before reverting to the crazy stuff.

So I changed the USBTTL and the serial cable and it started behaving normally.

And then I finally managed to repeat the problem

So RepetierHost disconnected. Turn on board. RepetierHost connected. (things go normal)
If I press reset button on board without disconnecting the RepetierHost, it starts getting crazy (but only on the Y axis).

In older firmwares you had implemented a reset when Connecting RepetierHost, but not in the new one. Do you believe its a Gen7 problem or some problem with the feature you removed from RepetierHost (I read it here). I hope it helps.

So after 2 days of trial and error I got a functioning XY.


By the way repetierHost shows a nice 2D plane on the 3d view , which is cool Now I will attach a pen and start drawing on a paper

Yes M106/107 need a wait but I heard a lot of people complaining that when the laser starts the lines are a bit "thinner" (engraving mode), so the wait can also help the diode laser get to the proper power (capacitor and everything). Well it need trial and error anyhow, Im still on the marking pen experiment

I will wait for your implementation to check it also . Where do you plan to use the tool enable/disable port? I mean physically on the board

By the way here you say that you implemented G2/G3 in 0.85 but here it says its not implemented.

I tried the example code G2 X90.6 Y13.8 I5 J10 E22.4 and it seems it works



thank again I hope my recreation of the problem was meaningfull to you

The host still does a reset on connect if the board supports it. It is only not an option any more. The new version always succeeds and doe snot need the information.

In the next solution you have a LASER_PIN which can be selected. Can be any board pin as it is only on/off. It can be overwritten with event system to do some PWM but that is not default implementation. Especially since pwm normally needs high frequency for laser to give a good result and that requires hardware PWM and that requires timers we often already use or are assigned to pins we can not use. Fan PWM is too slow with 16Hz.

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