Detecting Z-Probe Pickup on move command

fcwilt

@sinned6915 said in Detecting Z-Probe Pickup on move command:

I also tried to manually issue G1 Z-100 H1 but did not get anthing.

A G1 H1 Znnn move will only work if that switch is configured as a Z endstop.

Recall that a G1 H1 stops when an endstop associated with the same axis is triggered. If not endstop is triggered it stops moving when it has moved the specified distance.

For example, this will move until a Z endstop is triggered or Z has moved 50mm.

G91
G1 H1 Z-50

Frederick

sinned6915

@fcwilt paneldue doe not refresh fast enough to reflect the moment when the probe halves couple. i can not tell what the controller sees.

i am trusting the LED illumination as a failsafe indicator. the LED is mounted to the top half. it uses the same ground as the probe. so when the probe circuit is completed, the LED will light up.

when the NC is broken, the LED goes out.

my config lines for the probe as endstop:

M574 Z1 S2                                       ; configure Z-probe endstop for low end on Z
....
M558 K0 P5 C"^zprobe.in" H8 R0.5 F200 T9000 A1 S0.03

fcwilt

@sinned6915 said in Detecting Z-Probe Pickup on move command:

@fcwilt paneldue doe not refresh fast enough to reflect the moment when the probe halves couple. i can not tell what the controller sees.

i am trusting the LED illumination as a failsafe indicator. the LED is mounted to the top half. it uses the same ground as the probe. so when the probe circuit is completed, the LED will light up.

when the NC is broken, the LED goes out. .

So if movement stopped with the LED comes on it will be OK?

Frederick

sinned6915

@fcwilt EXACTLY!
probe not attached P=1000
probe attached, P=0

fcwilt

@sinned6915 said in Detecting Z-Probe Pickup on move command:

@fcwilt EXACTLY!
probe not attached P=1000
probe attached, P=0

So this switch is currently configured as a Z probe?

Frederick

sinned6915

@fcwilt yes, that is what i attempted with my M558 command. syntax and comments below

M558 K0 P5 C"^zprobe.in" H8 R0.5 F200 T9000 A1 S0.03
                                                ; K0 for probe 0, P5 for NC switch, C for input pin, 
                                                ; ^ for enabling the native pullup resistor on Duet2 hardware running RRF3  
                                                ; H dive height of 8mm, F300 probing speed 6mm/sec, T9000 travel speed 150mm/sec,   
                                                ; A3 number of probes 1, S0.01 max tolerance of 0.01

fcwilt

@sinned6915 said in Detecting Z-Probe Pickup on move command:

@fcwilt yes, that is what i attempted with my M558 command=

Just for your information you should be able swap the values returned by the probe, open versus closed, by adding a ! character to the beginning of the pin name.

Some folks home Z using Z endstop switches (I'm one of them). Some home Z using a Z probe.

When homing with endstop switches you use a G1 H1 command.

When homing with a Z probe you use a G30 command.

The important thing to note is that in both cases movements stops when the endstop switch or the Z probe is activated.

When homing using a G1 H1 command you have control over the direction of the move. So you can move toward an endstop switch at Z min or one at Z max.

When homing with a G30 command I think the direction is always going to be toward Z min.

So have you considered configuring this switch NOT as a Z probe but as a Z endstop switch and trying to use a G1 H1 command?

Frederick

T3P3Tony

while sensors.probes[0].value[0]=1000

so i have tested the logic using this macro:

while sensors.probes[0].value[0]=1000
  G91
  G1 Z0.01
  G90
  echo iterations
  if iterations=10
     break

With the following result when I go slightly past the Z trigger point (which i need to do to get this transition

M98 P"0:/macros/00_test"
0
1
2
3
4
5
6

ok

So i would test your while loop. You can make a that just does

echo sensors.probes[0].value[0]

and the manually move the z probe into a triggered/not triggered status to confirm it all works as you expect it.

sinned6915

@T3P3Tony here is a video of trying to execute the loop meta command.
https://photos.app.goo.gl/DYYfcTEyFbJhUGGw5

when i first tryed to run it, it complained that G0/G1 axis not sufficiently homed so I overrode it with M564 S0 H0.
then the bed moved and stopped. at that point the system appeared to be un-responsive. when I hit the STOP button PanelDue, I got a couple of error messages.

probe type- this is one thing that confused me.
https://duet3d.dozuki.com/Wiki/Connecting_a_Z_probe#Section_Mode_Num_5

but there was something that I thought I read that was RRF3 specific that said it was not case and I had to use Mode 4 instead if I wanted NO and it had to be on E0 endstop circuit. I can not find it now, but I am trying to remember if it was RRF3 or Duet3 specific.

@fcwilt I think you might be right abtou G1 vs. G30 . I think that to meake it work though, I need to redefine the probe to be active LOW so that it beleives its 'triggered' when the circuit comepletes.

T3P3Tony

try a loop with just an echo of the switch state and see if it reports the state change as you expect when you manually trigger it

sinned6915

@T3P3Tony said in Detecting Z-Probe Pickup on move command:

so i have tested the logic using this macro:

are you running that macro from the console on DWC or via terminal and USB cable?

is RRF reporting back the iteration values line by line as it runs?

I am trying to understand the differnce between the echo statement you posted and what I was using previously -

M409 K"sensors.probes[0].value"

T3P3Tony

@sinned6915 I am running it as a macro from within DWC (i.e. it is saved in a macro file not entered into the console line by line)

There is a limitation on how DWC report macro outputs when using DSF on SBC so the output of the macro is not reported until it completes, but you can see the Z axis raising by 0.01 each time it loops

sinned6915

@T3P3Tony should it matter that I am on Duet2 Ethernet?

sinned6915

@T3P3Tony I had to increase the iterations to be able to catch it. i did not think to chage the feedrate, only the iterations.

I had to issue a M564 command to overide movement before home, it gave me an error message otherwise.

while sensors.probes[0].value[0]=1000
  G91
  G1 Z0.01
  G90
  echo sensors.probes[0].value[0]
  echo iterations
  if iterations=100
     break

i manually deployed the probe. once the probe snapped into place, the bed stopped moving.
The console showed 41 iterations the system reported a probe value of 500, where before it was consistently 1000.

now i am trying to reconcile how this might be different than the original -

while sensors.probes[0].value[0]=1000
   G1 Z-0.5  F360

is it the break command at the end? I read the break to apply to the if iterations statement.

EDIT: I am wondering if changing to probe type 8 might be better being unfiltered.

T3P3Tony

@sinned6915 the break is only called if the if statement evaluates to true. If you only got to 41 iterations 41 then the while loop evaluated to false and ended before the if statement evaluated to true.

Using M564 makes sense if you have your bed unable to move below 0.

The 500 report for value, if only for a brief moment could just be the probe moving between the two levels.

Either probe type 5 or 8 should work in this case. 5 might be slightly slower to respond but i don't think that is the root cause of the issue. Also no it does not matter that you are on Duet 2.

Try much smaller movements. Don't forget that the move you send will complete, maybe 0.5mm is too much.

fcwilt

@sinned6915 said in Detecting Z-Probe Pickup on move command:

@fcwilt I think you might be right abtou G1 vs. G30 . I think that to meake it work though, I need to redefine the probe to be active LOW so that it beleives its 'triggered' when the circuit comepletes.

So you are determined to make it work using the switch as a probe and doing a while loop?

Frederick

dc42

@sinned6915, if you want to use a G1 command in a while loop with a test to stop movement, you will need to use M400 after the G1 command. Otherwise the G1 commands will be put in the move queue and will not happen instantly. That is why movement continues after the switch is triggered.

Alternatives are to configure the switch as an endstop switch and then use a G1 H1 move; or configure the switch as a Z probe and use a G30 move.

fcwilt

@dc42 said in Detecting Z-Probe Pickup on move command:

Alternatives are to configure the switch as an endstop switch and then use a G1 H1 move; or configure the switch as a Z probe and use a G30 move.

Bless you, good sir. Bless you.

Frederick

sinned6915

@dc42- the many movements filling the que and then clearing it out makes sense.

i think i discovered that by accident earlier too. with really small small steps, like Z=-0.01 it will move and 'softly' pickup the probe and stop.
when I change to a valuue of Z-0.1 i would still overrun it. Then i threw in an M400 and the behavior really changed.

@fcwilt I have been struggling the z-endstop logic all afternoon. as i have tried to show you, I already HAVE the switch set as both endstop and as probe, and I tried using the G1 and G31 commands before I got to this point. I have not doubted you, I just have not ben able to make it work. don't take it peronsally.

M574 Z1 S2 ; configure Z-probe endstop for low end on Z
and
M558 K0 P5 C"^zprobe.in" H8 R0.5 F200 T9000 A1 S0.03

it seems that to make it work, I HAVE to change the probe logic, and that is where I am getting tripped up. it also has to get changed back to probe the bed.

https://duet3d.dozuki.com/Wiki/Gcode#Section_M558_in_RepRapFirmware_Num_3

is where the RRF3 specific stuff was hidden at.

neither method is foolproof. as an engineer my brain is thinking not 'if this bad thing happens' but more 'WHEN this bad thing happens', which will cause the least amount of carnage.

fcwilt

@sinned6915 said in Detecting Z-Probe Pickup on move command:

@fcwilt I have been struggling the z-endstop logic all afternoon. as i have tried to show you, I alrady HAVE the switch set as both endstop and as probe, and I tried using the G1 and G31 commands before I got to this point. I am have not doubted you, I just have not ben able to make it work. don't take it peronsally.

I cannot find the configuration commands that set the switch to be an Z endstop.

Can you guide me to them?

Thanks.

Frederick