Original Rostock issue(s)

Hi,

i am building the original Rostock. I like the design and the simplicity.
I already have a Prusa i3, which i used to print the parts for the Rostock.

Now, i have set up the most things. All Motors are kind of working ( i will explain later why only "kind").

I use a Rumba board and the Marlin FW (with the Delta files of course)

I use only 3 mechanical Endstops (MAX) at the top. They work fine, so when i home the axes, all three goes up and homing fine.
I already set up the FW, with the rod lenghts etc.
But when i try to make a dry run, so i can see if everything is moving fine during a print, the three axes shooting down and crashing into the bed (don't have the carriage connected yet), so it does not stop after around 170mm as it should be.
I am pretty sure i need to tell in the FW that there are no MIN Endstops, but i can't figure out where.

the second thing is was wondering is more like a "does that have to be and can i change it" - thing.
After the homing the axes moves down a little bit and went upwards again to find the Endstops, that is good, i am sure that this have to be, but the 2nd run to go upward is extreme slow and the motor seems to be more shaking then going smooth (that is what i mean with kind of)

I hope you can help, as i have no more idea where to search...

Have you set the Z_MAX_POS correctly (apparently 170) in Configuration.h ?

Hi,

i don't understand, the z max. is 0 as there is the Endstop. right ?

Edited 2 time(s). Last edit at 05/27/2014 08:28AM by TheCrey.

No, even if your end stops are at the top, the top is still MAX (~170) and bottom 0 (think of 3D space coordinates).
That is the purpose of the 3 _HOME_DIR settings. You should have set them to 1 (for max). If it was set to -1 you also need to reverse your motors direction.

Your Z_MIN will always be 0. The min position is relative to your max. So if you want to be able to go lower, you need to increase the Z max.


I hope I have been clear ;-)

Edited 4 time(s). Last edit at 05/27/2014 08:56AM by Mikadoh.

HI,

sorry for the stupid quetioning.

The homing at the MAX Endstops is woking fine.

When i go down then, it should go down more then 170mm i think, this is not working at all.

There is not stupid question ;-)

Maybe I didn't understand you ?

If you want your printer to stop arround 170mm below the top, that is actually a matter of max position.

The Z_MAX_POS is not only a limit. It also let the printer known what is exclatly his position after the homing.
It is the max OK. But what is the max ? If you set the max to 170 then it kown it can only go down for 170mm before reach 0.

You should try to put the Z_MAX_POS at 170 or less and try carefully to go down to see if I'm wrong or not ;-)

Edited 4 time(s). Last edit at 05/27/2014 09:33AM by Mikadoh.

Hi,

when i look into the FW i find this

// Travel limits after homing
#define X_MAX_POS 90
#define X_MIN_POS -90
#define Y_MAX_POS 90
#define Y_MIN_POS -90
#define Z_MAX_POS MANUAL_Z_HOME_POS
#define Z_MIN_POS 0

if i understand you correct i have to change it to like that

// Travel limits after homing
#define X_MAX_POS 90
#define X_MIN_POS -90
#define Y_MAX_POS 90
#define Y_MIN_POS -90
#define Z_MAX_POS 170
#define Z_MIN_POS 0

================================================

What i acutally did was the following part changed in the FW as i thought this was the correct area

#define MANUAL_HOME_POSITIONS  // MANUAL_*_HOME_POS below will be used
// For deltabots this means top and center of the cartesian print volume.
#define MANUAL_X_HOME_POS 0
#define MANUAL_Y_HOME_POS 0
#define MANUAL_Z_HOME_POS 170 // For delta: Distance between nozzle and print surface after homing.

Well, actually your settings seems to be right.

#define Z_MAX_POS MANUAL_Z_HOME_POS
with
#define MANUAL_Z_HOME_POS 170

is the same as
#define MANUAL_Z_HOME_POS 170

So I think there should be something else.

When you go below the minimum position you wanted, what is your Z position ?
Send the M114 command to get the printer position.

If the Z position is negative then I think there is a parameter missing to prevent that, but I don't remember which one.

That sounds good, i am not at home right now, later that day, i will check that and come back to you. Thanks.

So, i am at home now, this is what i tried


This is how my FW looks like....

//#define MANUAL_HOME_POSITIONS  // MANUAL_*_HOME_POS below will be used
// For deltabots this means top and center of the cartesian print volume.
#define MANUAL_X_HOME_POS 0
#define MANUAL_Y_HOME_POS 0
#define MANUAL_Z_HOME_POS 100 // For delta: Distance between nozzle and print surface after homing.

Now i move the z down... and after a while i read the status and got this:

X:0.00 Y:0.00 Z:70.00 E:0.00 Count X: 287.08 Y:287.08 Z:287.08

The funny thing is, i changed the value from 170 to hundred bevause i was to much in Z, so i changes the limit to 100,,but i am now, as it looks like under the 100, but this is not possible as i am at the same hight as before... i pressed 3 times -10 at pronterface, booth times....

i really don´t know what to do any more

Here is an example....

now the code is this:

//#define MANUAL_HOME_POSITIONS  // MANUAL_*_HOME_POS below will be used
// For deltabots this means top and center of the cartesian print volume.
#define MANUAL_X_HOME_POS 0
#define MANUAL_Y_HOME_POS 0
#define MANUAL_Z_HOME_POS 50 // For delta: Distance between nozzle and print surface after homing.

and this is the result:

SENDING:M114
X:0.00 Y:0.00 Z:20.00 E:0.00 Count X: 237.08 Y:237.08 Z:237.08

So, the issue is solve, thanks to bill2or3 form the IRC chat...i used the rumba baord.. and the microstepper were to 16 steops, instead of 8... i changed. them and now all is working fine !

Thanks for the help ! So much.