Hi Volks,
the proximity sensor of my 3D printhead is broken, i need a new.
unfortunatly i dont can read nothing on the sensor, but i found this in the net.
it seems to me it is the same sensor, what do you think?
IMHO very expensive, the whole head is 133 US$ incl. shipping.
Thanks for your answers
Keep alive and kicking! 
Stefan
I think youre looking for a Ćffner / NC contact as the Contact is reported as 0x00 when the LED lights up but 0x01 when it turns off. Luban on the other hand reports āOpenā when the LED is dark and āTriggerdā when its lit.
So i cant 100% tell you what you need. Is the stuff on the case fo the sensor unreadable to find a datasheet?
Yes its nothing readable on my sensor, perhaps anybody can look on his for the needed Information?
Since the I do manual calibration 
Not as bad as I thought
My printjob will need over 60h thats worth the little work I think
Before you go too crazy, have you taken a moment to remove the side cover and reseat all the connectors on the control board?
I would probably fashion a guess that you would need the normally open contact in NPN (which is what you have loaded up) but that is not necessarily accurate, it could be N/C and or PNP as wellā¦
Im not really equipped to figure it out here at home easily.
This is a 3 wire sensor? If so, maybe i could take it apart and try to test it.
Edit: further pondering - i think it can be safe to say that if the sensor was NC, you would not be able to move the head downwards. It would be stuck telling you that your nozzle was too close to the build plate.
maybe simply removing the connector and trying to move down will further prove that point. if the contact is meant to be normally closed, that would mean the lack of signal would imply the limit is reached, so the controller would not allow you to move further down.
From there, it simply becomes is it the more universal NPN contact or is it a PNP contact (which is what i personally prefer because it is typically what logic controllers want for an input, at least for keyence and crouzet)
i have a device at work that would easily show me if i connected the three wires to it. you could also figure it out with some testing
Hope this helps!
I lay around this night and let my toughts spinningā¦
Is it possible to exchange the sensor with a little circuit that is triggert by a swich a opener or a closer?
I am a noob in electronics. But I think it must be possible.
What do you think?
@MooseJuice Yes it is a 3 wire sensor.
@xchrisd Thanks for the info!
Keep alive and kicking
There are ready to use sensors like industrial initiators to buy, it should not be really difficult to print or buy a holder and connect.
Sry not at the PC, quick Google search here:
Alternative, a hardware switch would do the same thing on other surfaces like the printsheet.
Yes, you can infact do that
If the voltage goes low upon sensing, you would need to consider this a normally closed contact instead of a normally open. i am surprised but not surprised at the same time, thanks so much for adding that information to the conversation @xchrisd
Its possible I am mixing it up, i dont use NPN often, so maybe I am misunderstanding it, however most microswitches have N/O and N/C so just find one that does just in case of the contingency!
however we would need to measure the output to see the actual voltage of the output itself. It may be smaller like 3v or it could be 24V, depending on the board. It may be that the sensor runs on 24V but has a lower voltage output (not likely, but it does happen and I have had to add relays to things to accommodate for that in the past, and since it is a 3 wire/transistor output on a printed circuit board level connector i donāt think iād rule that possibility out) however in my own experiences this did not cause any electrical issues but simply was not detected by the input. the more i think about it, if it was a four wire that would be more likely and in a 3 wire scenario it is probably a direct 12-24VDC output.
From there you would just run whatever voltage and polarity through NC and COM on a micro switch and when the microswitch makes contact the circuit would be complete.
if it were PNP it would be running the voltage + through the contacts and since its NPN we would be running the voltage - through them insteadā¦
The microswitch may provide some ābounceā, which in the case of this application I dont think would matter much, but if it was a counting application it would be chaotic because it would see multiple contact closures, and to avoid this would need a capacitor to even things out.
I am not an expert in electronics but I am pretty good with low voltage contacts from my job.
One could come up with any number of changes to the design including implementing the FiFix directly with a microswitch to avoid the proxmity sensor altogether, but i donāt think that would provide any better result.
@MooseJuice
You mean I have to measure the voltage on the sensors connector on the pcb in the Printhead? Is this right? The bouncing is no problem i think it reacts on first contact, then goes up a little bit and does the next.
Yeah I would just make sure the output pin reads 12 or 24V if you probe between the sensor output and + voltage, if it reads something else then we have to find a different way to wire it up, in the event the existing sensor has some kind of voltage reduction in its output.
This is not likely but entirely possible.
I guess that might be hard to do if your sensor is bad thoughā¦ so maybe a different test would be to jump between (-) and sensor input pin on the board, then try to move down to see if it lets you or not. repeat the same without making the contact. If you can see a difference between operation when you have the contact made and when you dont, then you know you are on the right trackā¦ sharing the information would be useful
I may be over complicating this - i just dont want to tell you to do something and have it damage your board, so i am erring on the side of caution.
Maybe i should bring home some equipment and perform these tests for you since you donāt have a functioning sensorā¦
I did some reconnaissance for the purposes of replacement here A350 - printing on glass
Output out the bench, out of the circuit is:
Triggered: 0.7V
Not triggered: 2.0V
Supply Voltage is 24V
@MooseJuice
That would be a very early Xmas present for me if you do so!
But only if it is not to many work for you.
Greetings
Stefan
eww, i was afraid of that. NPN or PNP?
If its NPN it might still work, but i think id be afraid to do that test.
We might have to find a pin someplace else on the board to tie in a switch. If the board is needing low voltage inputs, there may be the low voltage available someplace to use as a common.
I canāt see the whole part number so I canāt tell. Does it matter? Just adds complication, but both are fine.
These sensors are black boxes, they arenāt just a 3 terminal transistor. Only way to tell definitively would be look up the data sheet.
Well if trying to replace the prox with a switch, we would want to run the correct type of circuit through the common to the no or nc contact yes?
if its NPN (sinking) it would be applying (-) to the pin while if its PNP (sourcing) it would be applying (+)
Maybe Ill take home my banner engineering demo box and just try to confirm. it shouldnt be much trouble so long as there is a connector on the board i can remove to tie into with some pins.
Doesnāt matter - only thing that matters is the applied voltage at the mcu pin. Whether the sensor internals use a push or pull output setup is immaterial on the output.
PNP and NPN circuits can be made to output whatever you like depending on how itās configured.
I donāt know which of the 4 circuits this sensor uses.
Do not go in any risk of your machine for me, 
Its true that the only thing that matters is what goes into the pin, but i dont think we know what goes into the pin - thats the question isnt it?
well on an NPN circuit you are grounding where as a PNP circuit you are applying voltage? at best if you have it wrong nothing would happen, at worst it could create a short
maybe i am missing something here and dont realize it.
Inverted 3v3 signaling goes into the pin.
With the toolhead is powered but the sensor disconnect the IO line has 3.3V on it. It is being pulled up external to the sensor.
When the sensor is triggered is pulls that low, but I donāt know if there is a separate pull down resistor somewhere.
Iām trying to back into if thereās a pulldown in the circuit without having to reverse engineer it.
Out of circuit, on the bench, when not triggered there is 0mA from signal to ground. When triggered thereās 8mA.
This is looking at it from a different angle than I am used to, but i think maybe there is some logic that can be applied to answer my own question.
Sounds like we need to apply (-) to the pin to make the board register the input. So I would say that the input requires NPN.
Of course, you are way more engineeringish than I am, but broken down to the basics, i think what we are saying is if we find a 3.3v common someplace that would be what to use as common on a mechanical switch