K8200/3DRAG Auto Bed Leveling

Hello,
I am trying to get Auto bed levelling working with Inductive sensor
I have installed the sensor and it is triggering fine on Aluminium sheet place on heated bed- tested with M119.

I have modified the firmware as per Thomas Sanladerer
[www.youtube.com]
I set the Z off set at -.57 as per Thomas's method and this works fine for laying down first layer.

When I manually enter G28, G29 in to terminal all goes well and the routine appears to runs fine

However when I go to do an actual print I am getting big issue.
When I enter G28, G29 in to starting Gcode the ABL routine runs fine but when the print starts
it is off set so that it tries to print (my large calibration circle) too far to the right and too far back of the bed.
I have tried with Mattercontrol and Simplify3D and same issue

When I print with the same stl file and same firmware without the G28, G29 in to starting Gcode it prints fine (although not with the ABL in force)

This would suggest that my issues probably lie in the ABL settings in the firmware ?

My configuration.h file is here (although I realise its a big ask for some one to look in it)
Config.h file

(Mods: Hanging Z axis, K8204 Spindle, belt tensioners - all tested and worked fine for months)

I wonder if any body would be kind enough to offer some advice

thank You
Noel

Anybody got any advice - I have tried a load of different options but nothing having any positive impact
Including this
[reprap.org] ... Dimensions but this just offset everything and it tries to home way off the bed.

A few new observations :

When I home using slicer jog controls the NOZZLE homes to front left corner (which has always been home)
When I use G28 typed into terminal the SENSOR (not nozzle) homes to the centre of the bed (which I guess is the home in configuration.h)

When G29 (ABL routing runs) it seems to be going to off set points versus what I have in my configuration.h and what it is reporting back in terminal
i.e.

G29
<-Bed x: 10.00 y: 5.00 z: 0.47 (but its actually going to more like 2, 60
<-Bed x: 150.00 y: 5.00 z: 0.42 ( but its actually going to 145, 60
<-Bed x: 150.00 y: 140.00 z: 0.36 (similar issues)
<-Bed x: 10.00 y: 140.00 z: 0.60 (similar issues)
<-Eqn coefficients: a: -0.00 b: 0.00 d: 0.53
<-planeNormal x: 0.00 y: -0.00 z: 1.00

It then tries to print starting at the dead centre of my bed which results in prints off the right and back of the bed


When I use G0 to go to the points specified in configuration.h they go to correct location

When I revert to previous (non ABL) firmware all works fine so I know I don't have a mechanical problem

From Configuration.H
// set the rectangle in which to probe
#define LEFT_PROBE_BED_POSITION 10
#define RIGHT_PROBE_BED_POSITION 150
#define BACK_PROBE_BED_POSITION 140
#define FRONT_PROBE_BED_POSITION 5

Tearing what hair I have left out on this (last hack to my K8200 !!!)

tks
Noel
(Also posted on [forum.velleman.eu])

I fixed my issue with printer printing off the bed after G29

Link to fix

May be of use to others

tks
Noel