ROSTOCK HELP!!!

Ok guys, I dove head first into the printer scene and now im really paying for it. I have a classic rostock printer. Got all my guts from Sainsmart. [www.sainsmart.com] Ramps 1.4 and the Sainsmart A4988 drivers. Firmware is Repetier and am using Repetier host. My problem is when I send g28, the printer spazz's out. It is violent and random. I have adjusted the trim pots on the drivers and have tried every combination of firmware settings with no luck. Here is my configuration.h. [pastebin.com] I am beggining to think the drivers are borked. I am desperate at this point and have spent countless hours troubleshooting! Please help!

I do not use Repetier but ... if it moves too quickly then the obvious thing to check is your steps per mm (you probably have a too high number there).

Do you have really 8x microsteping activated with jumpers on your Ramps?
[reprap.org]
Do your steppers realy have 400 steps per rotation?

I dont´t think your drivers are broken. Setting up a printer for the first time takes a lot of time, can be frustrating but you learn a lot. It took me one week to find all these little snags, but now it works perfect.

I do not use Repetier and I don´t know yet how to home a delta exactly. Got a Mendelmax, use Marlin & Pronterface.

I think it migth have something to do with the logic of endstops, or directions. The printer does not get a signal that it hit the homeing switch. Which kind of endstops are you useing?

Best Regards,

Philip

I think you might be on to something considering I knew nothing of the jumpers lol. Will fix when I get home!

No not the jumpers. If you use opto endstops, you have to invert the logic. This is what I learned. Was not in the comments in the config.h. I think for Repetier it is this block:

//set to true to invert the logic of the endstops
#define ENDSTOP_X_MIN_INVERTING true
#define ENDSTOP_Y_MIN_INVERTING true
#define ENDSTOP_Z_MIN_INVERTING true
#define ENDSTOP_X_MAX_INVERTING true
#define ENDSTOP_Y_MAX_INVERTING true
#define ENDSTOP_Z_MAX_INVERTING true

This setting is right for microswitches. You home on MAX, so for Optos it should look like this, if you use optos...

//set to true to invert the logic of the endstops
#define ENDSTOP_X_MIN_INVERTING true
#define ENDSTOP_Y_MIN_INVERTING true
#define ENDSTOP_Z_MIN_INVERTING true
#define ENDSTOP_X_MAX_INVERTING false
#define ENDSTOP_Y_MAX_INVERTING false
#define ENDSTOP_Z_MAX_INVERTING false

Good luck,
Philip

Im using the mechanical endstops. I think its the jumpers considering i dont have any on the board at the moment and the motors act so random.

Ok, so I installed the jumpers on the ramps board for 1/8 step. The motors behave just like they should now but whenever I home once they get near the limit switches they spazz out again. Only this time less violently than before.

SOLVED, Switch jumper pins to 1/16th stepping. Homing works flawlessly now.

Ok, at least it looks like your steppers and steper drivers are correct.
I do not know Repetier so I do not have more ideas.

Except, you should check whether endstops work correctly. Use M119 to check their status. Press them manually (with your hand) and check witn M119 that they activate when pressed and deactivate when released.

It still can be related to feedrate and steps per mm if Repetier uses different speeds for homing and the rest of movements. These are questions for somebody who uses Repetier. You can try to set really low feedrates and accelerations tempolarily to see what impact it has. If you drive steppers too quickly, they will not have time to start to turn and instead they start skipping steps.

Check whether your steper drivers do not overheat. If they are running to hot (around 70°C or more), lower the stepper current. If they look completely cool, add current. Steppers can miss steps in both cases. Too high current (not enough torque to turn them). Too low current (steper driver thermal shutdown will switch motor off for the current - till it cools a bit). You probably do not have problem with too low current since they can move at least while homing. But you can have problem with too high current.

Edit: Opps you solved it while I typed the next comment Good luck with your printer.

Edited 1 time(s). Last edit at 10/13/2013 08:22PM by hercek.

What I did was start with baby steps... I took the arduino and a prototype breadboard (the kind you can just stick the components into and test) and played with the drivers and stuff before using the Ramps 1.4 board. It helped to be able to test each piece before assembly and to configure the drivers. Don't be afraid to play, you will learn much more. The a4988 drivers, too little current and they just sit there, too much and they spaz.

One step at a time....

Ok guys, After about a week or two of playing with settings (switched to the marlin firmware) I can home and run "dry prints" but I have run into a problem. Whenever the end effector moves from x-50 to x50, instead of being level the whole end moves in a bowl shape. Could this be a problem with the diagonal rods possibly not being the same length or a setting in marlin? For example if the end effector is at x0,y0, and z is set to right above the print surface and I move to x10, the z height changes. This happens in both directions. Any help is great!

Can be many things, but most probable are:
* wrong diagonal rod length, or
* wrong delta radius.