k8200: z axis too _when trying to change eeprom configuration _even worth! Have a Guess?thx

Dr_Froggy_rD

Dear all,

I tried first by reading here and there, and then I tried to do it myself...
I use Repetier host v1.6.
I used the printer defaut settings as explained on velleman website.
But with the newest version of everything.

So everything almost fine.
Except Z axis.  everytime I print the upper layers are allways like below the level it must be. I have to rotate the bolt by hand up and up every 10 min otherwise it happens again.

So I thought how I can calibrate the z axis.
I wanted to read the defaut settings with M501---> no info...
I do not know why I have no way to read the settings regarding the motors but it does not appear anywhere (Maybe I did not find it), and I cannot adapt it like I read elsewhere (on instructable.com) for other printers.

Then I read we can change in the eeprom settings part in repetier host.
For the K8200 I read z axis must be 2560 steps per millimeters. so I changed here.
but wrong --> the motor under defaut settings turns "normal- fast"
changing the value to 2560/saving in eeprom --> manual control panel --> moving z axis from 10 mm: the motor seems to read steps by steps and I had to wait about 10 min sothat it finish the command.
I thought ok if it is too slow, I need to decrease the number of steps---> it is even worth.

Sooooo What I have to change to get the right Z steps/ mm ratio on my K8200? For information I asked the printer to move 200 mm in total (orientation bottom to top) and I measured with a caliper the distance travelled results: 198mm only.

So it is seems I really need to change a setting somewhere to get it properly calibrated.

Can somebody help me?

Thx to everybody for reading and double thx to whom answering!

Regards

Froggy

Repetier

Doesit have professional spindle or just M8 rods? M8 has high friction, so limit speed to 2-5mm/s and low acceleration 50-100mm/s^3. 2560 is for direct driven M8 rods with 1/16 substepping correct. Make sure they are parallel and greased will or motor may block.

Dr_Froggy_rD

Dear Sir,

Thx for your answer.

So no way to compensate it by telling the software it must adjust the number of steps? 
If I do 100 Measurements at different speed with the same calibration problem of the z axis (allways the same difference with "must be" and "is" value.
Where can I modify the settings to overcome the problem?
I have a constant problem for lifting.

As I said I have to stay close the printeer and making lift by hand.
It is necessary to correct the deviations from the software. Please give me the instructions I need to set.

I will be very gratefull.

Froggy.

Repetier

Firmware is responsible to do it always correct (unless hardware prevents it). I already told you the possible reasons, but changing firmware settings depends on firmware, so read how to do it for your firmware.

Dr_Froggy_rD

Yes I understand. thanks again for your time.
The reasons are clear now. However, you did not answered my question.
(you know this joke whith two mathematicians in a boat - the two are lost - and cannot see any landscape to figure out where they are.
By chance they saw another boat with two people inside.
one of the mathematicians asked: "hahoi! I have a question! Do you know by chance where we are?"

The two peoples on the other boat answered:"Yes we know: you are on a boat!"
The mathematician to the other one:"they are both scientists like us, they answered correctly but we did not get the expected answer and we are still lost!"

So you see. You did not help me by telling me the reasons, I wanted to improve the calibration. you answered change the rod for a spindle or live with it.(more or less).
which is not wrong but not correct.
If you have told me: no, you cannot play with the settings to calibrate the printer, only way is to change to a spindle.
This is then correct. (but I doubt this is true as I readily read elsewhere)

So back to my point
But I thought we can change this in the eeprom config. or directly in the gcode from repetier host.
(The firmware is marlin)

Best Regards

Repetier

The problem is I'm not familiar with Marlin. I just know what settings have an effect but not how to change them in marlin. I always set them in configuration.h for marlin as described in configuration.h. That's why you wrote your joke, but the reason is I don't know what marlin can do in eeprom.

Dr_Froggy_rD

The joke was only about the correct answer but not the correct one that one may expect.
I have several others on the subject.
At least you give me an answer. I appreciate that.

thank again for your time and your answer.

PS:I must say I do not know either what marlin can do in eeprom I need to look at this feature

Ferencz

If you have in eeprom for Z axis value 2560 and set travel long to 200mm, travel is only 198mm - Replace value for Z axis with: 2585.858 

Result calculated: 2560x200=512000;  512000/198= 2585.858 

Dr_Froggy_rD

Dear all,

I asked almost the same question at velleman.eu.
As they use repetier host.
Point: before being able to do anything from repetier, some lines in the firmware must be modified using arduino 1.0.6 (if I right understood)

Without this, any modification in eeprom setting cannot work.

Regards