Tried both and got the same result. It seems that the printer is resetting its height before a dive, causing it to dive too short. If you obstruct the probe early with your finger, it works as intended. However left to itself, it will not lower enough for the probe to even reach the bed.

I've run it at 250 and 500 before, but I will try a little higher and see if that helps. Won't be able to test till tomorrow. Thank you for still checking in.

I have turned the Z acceleration down quite a bit, from 250mm/s^2 to 100mm/s^2. I also changed homez.gcode to utilize the endstop. With the new homez.gcode I get very consistent zeroing.

To test the probing I do the following set of commands.

M558 P9 F200 T9000 H5 A3     ; set probe type to BLTouch, feed rate to 200mm/min, travel between points to 9000 mm/min, dive height 3mm, probe three times

G1 X0 Y0 F9000     ; go to x0 y0
G28 Z                     ; home the Z axis
G1 Z4.5 F200          ; move 
G30                         ; perform single point probe

This code should cause the Z axis to be correctly home, then probe the same spot three more times. The result is similar to before. The homing probe will be performed correctly (it is using a G1 S1 Z-1300 F200, followed by a G92). I then make sure that the probe is within the dive height to the bed based off the measurement just performed. The probing move is then started but the probe will stop a mm or two short of the bed then state "Error: Z probe was not triggered during probing move".

On the probing move it is visibly not descending far enough before stopping and reporting the error. No heaters or fans are running during any of these tests.

It is a moving gantry. Our bed weighs about 110kg and consists of a metal sheet on a galvanized steel pallet. Moving the bed was not feasible.

The Z axis consists of 2 threaded rods but the motion itself is on precision linear rails.

I'll try turning the Z acceleration down and report back with the results tomorrow.

I'd be very surprised if it was skipping steps. The Z axis is driven by two Nema 23's on an external high power driver (DM860AC). We have run the Z axis on big moves vertically and it does them correctly at 300 mm/min. We have run the motors to the point where they start to skip and do not see/hear skipping steps. We have run the Z axis up to 500 mm/min but slowed them down due to vibrations.

It will also probe correctly on the first attempt. Even if we set M558 A >1 it will probe it once correctly, then fail to probe close to the same distance on the second attempt. This can be seen in the linked video above.

Thank you.

Do you have any thoughts to the issue above relating to probing? It's a very odd situation and I have been unable to find others with the same issue even.

Is there a way to trigger that macro to run on boot?

Could you actually provide a more detailed example of M589? I tried doing that but kept getting an error stating incorrect parameters.

I'll give that a try tomorrow. It is running as part of a bundle of wires which contains multiple steppers, a heating element, and a fan. The steppers and heater are in shielded wire, but the lengths are long enough we could even get interference from fluorescent lights (which I've experienced with telephone wires).

Maybe I'll try a small capacitor and playing with the trigger value. We have been testing with the heaters off for now.

What confuses me is that M401 and M402 both work. G28 Z works. But when we go to G29 it doesn't behave correctly. We even noticed this when we swapped the BLTouch for an inductive sensor I had on hand.

I'll also be sure to put the build up on the forum. We're focused on finishing the project right now, but afterwards will be hitting up some of the various 3D printer sites and communities.

Tried changing the Z trigger height to positive. Might have been a mistake. It did not solve the issue.

For the Z axis we are using M12 threaded rods. Our gantry is about 1.5mx1.5m and is carrying about 10kg of weight. We can't go much faster or else we get vibration build up. The Z axis is about 2m tall. Future work is to upgrade them to lead screws but we were limited by cost and lead time.