Detecting Z-Probe Pickup on move command

sinned6915 · 2 Oct 2021, 17:50

@T3P3Tony if i manally deploy the probe, everything works as expected.
here is old vid if it helps. https://photos.app.goo.gl/3KEhDJKUdSbfTjS2A

the switch is your garden variety SPDT microswitch. the NC - C are connnected to the magnets. when the halves couple, the circuit is complete to the controller.

i incrementally built the move commands to align the carraige over the dock. i have verified that with no probe, P=1000. When I manually couple the probes, P=0

the issue is the while loop.

the controller is not reazling the circuit is complete and the probe value goes from 1000 to 0.

if you watch the video from this point, you see the point where the probe is coupled- the LED lights up. then as the bed continues to move, the probe is trigered and the LED goes out as the switch is depressed.

https://youtu.be/bkqzr3B-ufs?t=10

i will make a macro of just the loop and post results in a moment

fcwilt · 10 Feb 2021, 18:09

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

the issue is the while loop.

the controller is not reazling the circuit is complete and the probe value goes from 1000 to 0.

Does this switch change state at the correct location for stopping movement?

If so did you consider my comments about using the switch as a temporary Z endstop which would stop a G1 H1 move when the switch triggered?

Thanks.

Frederick

sinned6915 · 10 Feb 2021, 18:10

the statement by itself does does not work.
i made a macro to execute it -

homes X & Y axis. I even gave it an M564 S0 H0

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

fcwilt · 10 Feb 2021, 18:15

@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 · 2 Oct 2021, 18:21

@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 · 10 Feb 2021, 18:21

@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 · 2 Oct 2021, 18:21

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

fcwilt · 10 Feb 2021, 18:22

@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 · 2 Oct 2021, 18:25

@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 · 10 Feb 2021, 18:35

@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 · 2 Oct 2021, 18:48

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 · 10 Feb 2021, 18:49

@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 · 10 Feb 2021, 18:53

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 · 10 Feb 2021, 18:58

@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 · 2 Oct 2021, 19:38

@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 · 10 Feb 2021, 19:04

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

sinned6915 · 2 Oct 2021, 19:23

@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 · 10 Feb 2021, 19:39

@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 · 10 Feb 2021, 19:51

@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 · 10 Feb 2021, 22:22

@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.

	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

	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

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

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