Understanding Endstop and Z Probe

SignPostMan

I am using a Duet 3 with 3 expansion boards for each of my stepper drivers. I sure this is a newbie question but I don't understand the relationship of the Z Endstop and the Z-Probe. When I configure my endstops to the expansion boards I can get the Printer to home X,Y and Z no problem. When I try to run mesh bed I get G29 Mesh Level Compensation, I get Error: Z probe already triggered before probing move started. I am using a simple microswitch for the Z Probe

I am also not sure the relationship of the Z probe type and switch and the Z endstop. How is the Input Pin and Modulation Pin used?

; Endstops
M574 X1 S1 P"!^40.io1.in" ; configure active-high endstop for low end on X via pin !^40.io1.in
M574 Y1 S1 P"!^42.io1.in" ; configure active-high endstop for low end on Y via pin !^41.io1.in
M574 Z1 S1 P"!^43.io1.in" ; configure active-high endstop for low end on Z via pin !^43.io1.in

; Z-Probe
M558 P5 C"io5.in" H10 F120 T6000 ; set Z probe type to switch and the dive height + speeds
;M558 H30 ;*** Remove this line after delta calibration has been done and new delta parameters have been saved
G31 P500 X0 Y0 Z2.5 ; set Z probe trigger value, offset and trigger height
M557 X15:2300 Y15:1300 S200 ; define mesh grid

fcwilt

@signpostman

What boards are you using?

A Z Endstop is totally separate from a Z Probe.

When using a simple switch as a Z Probe you don't have a modulation pin, just an input pin.

If the probe is being reported as active at the start of a probe just change C"io5.in" to C"!io5.in" to invert the signal.

Frederick

kb58

Yup. If it's reporting "active" when enabled, it means that the switch is already in the "active" state (defined by you as a high or low signal), when the sensor was enabled. It's either what fcwilt said above, or it could be a shorted or open switch, depending how it's wired.

If there's some question of what the switch is doing, unplug it from the controller board and put an ohmmeter/continuity tester on the connector leading to the switch. It'll either be shorted or open. Now activate the switch, and it should go to the opposite state. If it does, there's nothing wrong with the switch or cable, so the question becomes: is the voltage level being fed to the controller board what's expected by how you have it configured?

SignPostMan

I actually have the Z Switch attached to the 43.io1.in . and there is nothing attached to the io5.in pin. but without a pin in the Z probe M558 the printer would not home.

jay_s_uk

@signpostman then you have it configured incorrectly.
remove the line

M574 Z1 S1 P"!^43.io1.in" ; configure active-high endstop for low end on Z via pin !^43.io1.in

and edit M558 to include the correct pin
edit your homing files to use G30 for Z rather than G1 H1

fcwilt

@signpostman said in Understanding Endstop and Z Probe:

I actually have the Z Switch attached to the 43.io1.in . and there is nothing attached to the io5.in pin. but without a pin in the Z probe M558 the printer would not home.

Do you a switch for your Z Endstop and another switch for you Z Probe?

Frederick

fcwilt

@jay_s_uk said in Understanding Endstop and Z Probe:

@signpostman then you have it configured incorrectly.
remove the line
M574 Z1 S1 P"!^43.io1.in" ; configure active-high endstop for low end on Z via pin !^43.io1.in
and edit M558 to include the correct pin
edit your homing files to use G30 for Z rather than G1 H1

Unless he has both a Z Endstop switch and a Z Probe switch.

I always include a Z Endstop sensor on my printers as it leads to faster homing and simpler homing code.

Frederick

jay_s_uk

@fcwilt whereas none of my prints (except the delta of course) have a z endstop.
but he did already say he had nothing connected to io5

SignPostMan

@jay_s_uk Looks like I cannot attach Z probe to the M558 only Z probes 8 and 9 are supported on expansion boards

jay_s_uk

@signpostman P8 is fine as a replacement for P5

SignPostMan

Thanks everyone for your input!
I think I got it.
I removed the Z-Probe pin, and it now works completely.