G30 Behavior on very heavy gantry

jrockland

Can we change the G30 behavior ?
I'm working on a heavy gantry unit and went the z probe is activated, the motor quickly reverse to go back up a bit.
I would love to :
-Quickly pause at the bottom to absorb the shock
-Act like X/Y : Go up a bit then slowly go back down to check Z a second time.

Please let me know, thank !

fcwilt

@jrockland said in G30 Behavior:

I'm working on a heavy gantry unit and went the z probe is activated, the motor quickly reverse to go back up a bit.

Don't know what you mean.

I would love to :
-Quickly pause at the bottom to absorb the shock

Don't know what you mean. Bottom of what? What shock?

-Act like X/Y : Go up a bit then slowly go back down to check Z a second time.

Here is my M558 for my BLTouch Z probe:

M558 P9 C"^zprobe.in" H2 F120 T12000 R0.2 A10 S0.03 ; set type for BLtouch and set default parameters

Notice the A and S parameters.

What these values mean is a G30 will probe up to 10 times (the A parameter value) until 2 consecutive readings are taken that are within 0.03 (the S parameter value).

If no 2 consecutive readings meet that criteria all 10 readings will be averaged.

If you wish to force the averaging of a number a readings set S to -1.

For example A5 S-1 will take always probe 5 times and average the readings.

Frederick

Phaedrux

No need to change G30, since you can already temporarily change the Z speed, jerk and acceleration (M201, M203, M566) to lower values before the G30 and then change them back afterwards.

jrockland

@Phaedrux True, and if I change it in homeall it should apply every time it receive a g28 rights ?

jrockland

@fcwilt Phaedrux answered my question already, but regarding the part you don't understand: My gantry weight about 30lbs on that printer. When you move 0.2-0.5 lbs around you can stop really fast and change direction without too much issue. When you move a big machine it is a bit different: You have to calculate acceleration and deceleration.

Thank for the M558 A/S, I will look into it. I don't think they are set properly on that machine.

jrockland

@Phaedrux actually doesnt work, when it does down to sense the speed/accell/jerk wont affect the stopping motion. It stay ruff even with the jerk and accell down to 1mm/sec.

Phaedrux

Are you talking about the initial stop when the probe triggers or the move to return to the dive height after it triggers?

There's not much that can be done about the stop other than reducing the dive speed.