Rostock Mini G2S Auto Level Malfunction

[brent_jackson]

Hi there, I'm having issues with the G29 auto level command on my new system.

The behavior I see is that G29 causes the print head to descend to about 60mm above the heat bed with X slightly positive and Y at about -30mm. It moves slowly counterclockwise at that height for about 5 seconds and then quickly seeks out other points (which I assume is a probing pattern) while quickly ascending. It strikes the top limit switches and I have to click Emergency Stop to prevent damage.

Log file output:
21:15:10.424 : N60 G29 *4
21:15:30.109 : Bed x: 31.50 y: -31.50 z: 99.97
21:15:30.588 : Bed x: 10.50 y: -31.50 z: 109.96
21:15:31.068 : Bed x: -10.50 y: -31.50 z: 119.95
21:15:31.562 : Bed x: -31.50 y: -31.50 z: 129.94
21:15:32.041 : Bed x: -31.50 y: -10.50 z: 139.93

Using 24 Aug 2015 firmware with the following values changed for my build:
#define X_PROBE_OFFSET_FROM_EXTRUDER 1.00 //20.35
#define Y_PROBE_OFFSET_FROM_EXTRUDER -20.00 //-11.75
#define Z_PROBE_OFFSET_FROM_EXTRUDER 4.0 //-1.2

I suspect that the following 2 default values in the firmware are responsible for this behavior:
#define Z_RAISE_BEFORE_PROBING 100 //How much the extruder will be raised before traveling to the first probing point.
#define Z_RAISE_BETWEEN_PROBINGS 10 //How much the extruder will be raised when traveling from between next probing points

Steps to reproduce:
Using Repetier-Host GEEEtech V0.90D
1. On Manual Control tab, click Home icon. System homes to top limit switches.
2. Send G29 command.

[Mark]

Could the printer work without G29?

[ezrec]

It seems like your endstops are not reporting correctly.

Verify the function of your endstops with the 'M119' command.

They should all report as 'open' normally, and 'TRIGGERED' if the carriage is touching the endstop.

I noticed that the wiring documentation (near the end of the G2S build manual) has a different wiring than what the endstops came out of the package with. (documented as pins 1 & 3, but packaged as pins 1 & 2).

If your endstops are 'backwards' (as I suspect) then swap pins 2 (NC) and 3 (NO) on the endstop that is in error.

If M119 never changes (always triggered or always open) then you probably have a loose connection at one of your endstops.

Use a multimeter to verify that the endstop is switching, and if not, check that you have a secure connection at the endstop switch. I had to re-crimp mine, they were a little loose.

[brent_jackson]

Yes, after some significant tweaking to get the bed perfectly level manually and set the printer height in firmware and Repetier (to 204.3), and editing out the G20 auto level command from the Slic3r-generated G-code I am able to print my first object successfully. Printing accuracy isn't spectacular and one corner of the object appears rounded where it should not be.

In any event, I purchased this model specifically because of the autolevelling feature so I would like to get that function to work.

[brent_jackson]

Video of failed auto level behavior posted to https://www.youtube.com/watch?v=9wMnkB3hA50

[brent_jackson]

There's a typo in my message above. It should, of course, read G29 for auto level rather than G20.\

My message was wrong. My printer is still not working using G29.

[digiex_chris]

That's classic symptoms of the firmware thinking the probe switch is always triggered. The most common cause of this is the wrong terminals on the switch being used. I can't remember which is the correct pins, but take a look at your auto level switch. If you have the wires on the outside two terminals, it's wired wrong. You should have one wire on the terminal that is under the switch hinge, and one wire that's on the center terminal.

[amdpit]

same here i have same problem, did You resolve it ?

[brent_jackson]

THANK YOU CHRIS!!!

That was indeed the problem. I had connected the switch leads to the 2 outer positions such that when the probe was down and not in contact with the print bed it would send Triggered. This in the instructions under the Check the Status of Endstop section, step 2. But I read it incorrectly.

The system is now auto leveling correctly.

[wirecase]

Thank you so much! that did the trick for my machine too!