Some dudes about BlTouch use...

peirof

Hi,

there is a concept that I am not clear about, about the use of the Zprobe, a BlTouch.

In config.g, I have this line "G31 P25 X-28.00 Y-13.00 Z0.90", which defines the distance from the (extended) PIN to the nozzle. As you will see, the distance in X is considerable

But this displacement. When does it go into effect?

G31 is NOT used

When you use G30, to prove a point

G31 is used

When you use G32 (Execute the commands in bed.g, which is composed of several G30 commands) with which DUET calibrates Z
When you use G29 (Mesh bed probe), you get the heighmap defined by M557

Now the doubts with examples:

CASE 1

I have the print head in (X0,Y0), and by DWC, I send the gcode ("G30"), the printer will lower the PIN of the BlTouch, and then it will reduce the Z, until the PIN touches... but Since the print head is at (X0,Y0), in reality, the height I will have tested will be (X-28,Y0)

CASE 2

I have the print head in (X0,Y0), and by DWC, I send the gcode ("G32"). Duet looks at the file ("bed.g"), which is made up of a series of points, for example 3 [(P1:X0Y200),(P2:X-200,Y-200), (P3:X200,Y -200)], and here the doubt, I see 2 options:

Case 2.1- The spindle moves to those points [(P1:X0Y200),(P2:X-200,Y-200), (P3:X200,Y-200)] and measures the height, with G30, executing (G30 P0 X0 Y200 Z-99999, G30 P1 X-200 Y-200 Z-99999, G30 P3 X200 Y200 Z-99999), and with the obtained Z calibrates the Z

Case 2.2- The spindle moves to those points CORRECTED BY G31[(P1:X-28Y200),(P2:X-228,Y-200), (P3:X172,Y-200)] and measures the height, with G30, executing (G30 P0 X0 Y200 Z-99999, G30 P1 X-200 Y-200 Z-99999, G30 P3 X200 Y200 Z-99999), and with the Z obtained, calibrate the Z

CASE 3

I have the print head in (X0,Y0), and by DWC, I send the gcode ("G29"). Duet looks in config.g, and starts testing the points defined in M557, for this example let's say (M557 X-200:200 Y-200:200 S100). The doubt in this case is similar to case 2, it is if when you go to a point to test it, use the G31 correction, that is, so that it is not long, I will only use 1 point, the first:

Case 3.1- The head moves to the points defined by M557, the first (X-200 Y200), and checks the height of all, to get the HEIGHMAP

Case 3.2- The spindle moves to the points defined by M557 CORRECTED BY G31, the first (X-228 Y200), and checks the height of all, to get the HEIGHMAP

General doubt, if the point, if the established correction G31 is applied, for example in the last case (X-228 Y200), will remain outside the limits of the bed. What would happen?

Phaedrux

@peirof said in Some dudes about BlTouch use...:

will remain outside the limits of the bed. What would happen?

It will skip and points it cannot safely reach.