Inductive sensor for Ormerod 2

I could do with some advice please.

I want to try an inductive sensor for bed height instead of infra red. I print onto a Gecko plate which are stainless steel with a special varnish coating. I have just purchased an inductive sensor and circuit board from Reprap 3DPrinter who are based in France, see this link: Inductive Sensor with circuit board Like many of these sensors the voltage range is 6 - 36 volt. The circuit board takes the 12 volt input and gives an output of 5 volts.

My question is which of the current Z probe connector pins would I connect the output of the sensor to and do I need to make any changes in the config.h file?

Any help greatly appreciated.

Brian

See [duet3d.com].

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Hi Dave, thank you for pointing me to that page.

The sensor I have bought is normally open, the description does not say if it is a PNP or NPN type.

The output is 5 volt, is the mention of a diode in series in order to drop the voltage? not sure how though as I thought the voltage drop across a diode was only 0.6 volt.

Will I need to set up a different X stop if I use the inductive sensor?

Sorry for all of the questions.

Brian

Hello Brian,

you should read the description precisely. The diode is connected the other way round. So if the output is 5V there is no current as 5V is higher than 3,3V. If the sensor is triggered (if NO easier to explain) the output voltage drops to 0V. Now the current can flow and the input is also triggered.

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Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.

Hi Dave, my apologies, that is now clear.

Can you suggest how I would deal with the X axis endstop as currently this depends on the Z probe.

According to the original instructions two of the wires for the Z probe are connected to the extruder endstop pins.

This leaves the X endstop pins free so could I wire a micro switch into these two pins and would that work ok?

I appreciate your help, you seem to be the only one with this knowledge.

Regards,

Brian

Yes you can use a microswitch for X homing. Define where it is in the M574 command, and use parameter X0 in the M558 command to tell the firmware that the Z prove is not used for X homing.

Have you considered using a better IR sensor instead of an inductive sensor?

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Hi Dave,
I did consider using your mini sensor but from posts I have read I got the impression that a steel print surface with a coating which is what I use does not work very well with the IR sensors.

If you can convince me otherwise I would be happy to give yours a go, I can always use the ordered inductive sensor for a different project.

Regards,

Brian

What is the nature of the coating, and how thick is it?

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

It is only a few microns thick, it is a sort of grey selulose lacquer with a dull sheen.

Made by these guys Gecko heated build plate

Brian

That will probably work well with the IR sensor then. But steel plate is also an ideal target for inductive sensing.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Hi Dave,
not sure how I "Define where the X microswitch is in the M574 command"

Many thanks,

Brian

Lookup M574 in the gcodes wiki page.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].