try to use delta grid on my 340x * 300y Cartesian printer. when i start G31 code, it only probe square and not rectangle no matter how i play with the delta-grid.max_x, delta-grid.max_x and radius value. how do i set this?
leveling-strategy.delta-grid.enable true
leveling-strategy.delta-grid.radius 90
leveling-strategy.delta-grid.size 7
mm_per_line_segment 1
leveling-strategy.delta-grid.is_square true
leveling-strategy.delta-grid.max_x 170
leveling-strategy.delta-grid.max_y 150
It sounds like right now it only knows how to do a square
oh, didnt know that. thanks for the confirmation 
@Arthur_Wolf im using proximity sensor permanently attached to my printer (not using z endstop)
so i add using G30 Znnn to automatically find the bed in gcode. now my problem is can i adjust the z offset in RepRapDiscount LCD Controller?
adjust configure> z home ofs in LCD doesnt seem to do anything.
sometime i need to fine tune the z offset to make it stick better, manually edit the g30 znnn in gcode everytime is very inconvenient. possible to make z home offset in LCD to work ??
@David_Wong I don’t know I have never used this that way, maybe somebody else will know
proximity sensors make very bad, inaccurate probes FWIW.
setting homing offset requires you to home in z to make use of it. that is why it is called a homing offset. tuning the z offset live requires you to use WCS which is documented (G54, G10 L2 etc)
So it is possible for me to use the probe (proximity sensor in my case) as a leveling probe and z homing endstop?
Possible?
you could but as I said it will make a useless probe as you need a point contact to do zgrid probing, not some approximate area on the bed. The work well as endstops though ,sop long as they detect the exact same spot on the bed each time. Proximity probes generally return different results depending on where on the bed they probe or if they are close to an edge