Welcome! Log In Create A New Profile

Advanced

Can not understand probe offset. Help please

Posted by GITRDUN 
Can not understand probe offset. Help please
January 20, 2018 11:00AM
For the life of me i can not wrap my feeble mind around the probe offset and what the affected settings should be. I need some help. Ive spent 25 years manually programming CNC equipment and using CadCam software for the last 7 or 8 years. I dont know why this turns my brain inside out but i just cant nail it down.

Had it working great and ended up changing to a 18mm inductive probe . After making a new probe mount which moved it to the side of my nozzle i cant get Marlin to compile again.
Here is my current configuration settings for the new setup.

#define X_PROBE_OFFSET_FROM_EXTRUDER -52.75
#define Y_PROBE_OFFSET_FROM_EXTRUDER 0


#define X_BED_SIZE 230
#define Y_BED_SIZE 135

#define X_MAX_POS 230
#define Y_MAX_POS 135

----------
(WHAT SHOULD THESE BE TO WORK ?)

#define LEFT_PROBE_BED_POSITION
#define RIGHT_PROBE_BED_POSITION
#define FRONT_PROBE_BED_POSITION 0
#define BACK_PROBE_BED_POSITION 120
---------

Any help greatly appreciated.
Re: Can not understand probe offset. Help please
January 20, 2018 12:18PM
The Probe offset is the x,y and z distance from the center of the nozzle to the center of the probe.

If you need help if you explain where the probe is in respect to the nozzle we can assist you in the number changes.

From what I read the probe is exactly 52.75mm to the left of the nozzle. Is it above or below the nozzle.

Edited 3 time(s). Last edit at 01/20/2018 12:40PM by Roberts_Clif.
Re: Can not understand probe offset. Help please
January 20, 2018 12:40PM
Well i noticed i had the configuration opened up in an older version of Arduino for some reason. I opened it up in the latest version and it compiled with making one minor change. I swear every time i want to make a minor change to anything its like starting all over and having to re learn everything from square one. Maybe im just getting to old for all this modern software.
Re: Can not understand probe offset. Help please
January 21, 2018 08:36PM
The very first bed leveling firmware that came out was the 3-Point leveling. It used a model of the print bed being a plane that can be tilted. The author simplified what the user would have to specify by introducing the concept of
``` <---<<< GitHub code quotes!!!
#define X_PROBE_OFFSET_FROM_EXTRUDER 38 // X offset: -left +right [of the nozzle]
#define Y_PROBE_OFFSET_FROM_EXTRUDER -7 // Y offset: -front +behind [the nozzle]
#define Z_PROBE_OFFSET_FROM_EXTRUDER -10.4 // Z offset: -below +above [the nozzle]

```
The author of that firmware made it very easy for anybody that wanted to use it configure it to their machine... (Those numbers are for my Folger Tech i3-2020. Check out: [github.com] )

Edited 2 time(s). Last edit at 01/21/2018 08:41PM by Roxy.
Re: Can not understand probe offset. Help please
January 22, 2018 05:39AM
Quote
GITRDUN
Well i noticed i had the configuration opened up in an older version of Arduino for some reason. I opened it up in the latest version and it compiled with making one minor change. I swear every time i want to make a minor change to anything its like starting all over and having to re learn everything from square one. Maybe im just getting to old for all this modern software.

I have been repairing computers since the 1970's When a small computer took a up an entire wall of a large room with 9 track tape drive storage.
Bill Gates had just acquired the DOS (disk operating system) for $50,000.
When the first machines were available only as kits. SWTP was a kit manufacturer and had no assembly facilities.

Just hang in there, it is really simple after the initial Gestalt process.

Edited 1 time(s). Last edit at 01/22/2018 05:41AM by Roberts_Clif.
Re: Can not understand probe offset. Help please
January 30, 2018 07:12PM
I still have some old CNC machines that have paper tape readers and facit punch ports to input or output the part program. Its amazing how much things have changed just in my lifetime and im not that old.
Re: Can not understand probe offset. Help please
January 31, 2018 07:44AM
I feel young, my mind is still clear and learning as fast if not faster the the youngsters of today. I just don't know who that old guy is in the mirror I have to shave every morning.

Now that we set the fact straight and we are young enough to master this simple 3D Printing innovation. How is you 3D Printing progressing.
Re: Can not understand probe offset. Help please
February 02, 2018 09:44AM
Dear Community,

I have an Anet A8 3D printer where I succesfully changed the firmware to Marlin 1.1.8.
Before that I worked perfectly with the originall Anet firmware.
I istalled an Inductive Sensor Probe to the head (next to the cooling fan front left side.

I'm suprised, it seems that the printing area reduced or X &Y coordinates or shifted after I set the probe offsets.
The auto bed leveling prints squares try to print outside of the bed. All the printing seems to be shifted and not in the center.
The Autohome work correct on Z axis as well, the sensor is above the bed. Front -Left corner.

Firmware setting which can be relevant to this are the follows :

#define X_PROBE_OFFSET_FROM_EXTRUDER 37 // X offset: -left +right [of the nozzle]
#define Y_PROBE_OFFSET_FROM_EXTRUDER 50 // Y offset: -front +behind [the nozzle]
#define Z_PROBE_OFFSET_FROM_EXTRUDER 0 // Z offset: -below +above [the nozzle]

I guess this is just for Auto bed leveling purpose :
#define LEFT_PROBE_BED_POSITION 40
#define RIGHT_PROBE_BED_POSITION 190
#define FRONT_PROBE_BED_POSITION 50
#define BACK_PROBE_BED_POSITION 170

#define AUTO_BED_LEVELING_BILINEAR //JMF changed for auto bed levelling

#define Z_SAFE_HOMING //JMF changed for auto bed levelling probe has to home above the bed

#define X_BED_SIZE 220
#define Y_BED_SIZE 220

What al of this mean : ?

// Travel limits (mm) after homing, corresponding to endstop positions.
#define X_MIN_POS 0
#define Y_MIN_POS 0
#define Z_MIN_POS 0
#define X_MAX_POS X_BED_SIZE
#define Y_MAX_POS Y_BED_SIZE
#define Z_MAX_POS 240



All the rest is from the basic Anet A8 Marlin config.h from the install folder.
I hope that the usageof the inductor probe is not to lost printing areas.
Please help me what I look over.

Thanks for your great support in advance.
Attachments:
open | download - Configuration.h (65.2 KB)
open | download - Configuration_adv.h (63.4 KB)
Re: Can not understand probe offset. Help please
February 04, 2018 04:19AM
One thing what I observed additionall that.

Measured bed center 110mm and 110mm are at X:142 and Y:116 why ?
Sorry, only registered users may post in this forum.

Click here to login