Calibration on i3 MK3s with SuperPINDA fails. SuperPinda is measured and seems to work!!
Hello Prusa Open Source 3D printing comunity.
I am a beginner in 3D-printing an have recently bought and assembled a "far-east" brand new MK3S-kit. There are absolutely no assembly issues at all (as far as I experienced by now) but I am running into electronical problems.
Maiboard: Einsy RAMBo 1.2e (printed on board). SuperPinda mounted and adjusted (properly I think). Firmware: 3.14.0. Now to the behaviour:
The printer starts its calibration process. Both fans OK! X-axis = OK. Y-axis = OK. Z-axis =OK. Z-axis moves upwards, touches the black limiters on top and alignes, moves down a bit, moves the extruder to the far left, steps a bit to the right... Then: Calibration process stops: "Bed leveling failed. Sensor didn't trigger.". System wants to be resetted.
I start the "auto home" feature. X-Y-Z axis are moved by all steper motors to an upper left position. Bed is moved backward.
I start the "Z-leveling" feature. Extruder and SuperPinda is moved downwards, downwards, downwards.... and crashes on the heatbed (outch). The X-axis is heavily bent, the bed is forced downwards (1 cm), rattling noise is coming from all moving parts: RESET!!!
I checked the (only?) sensor (SuperPinda) on the mainboard: 3 wires, brown, blue, black. Brown = (+), blue = ground (-), black = signal (5v). I did the "metal test". Pinda probe light turns off when "metal" is detected (I don't know wether "metal" or "magnet/induction" is responsible). Pinda probe signal is handed over to the "hardware": In the "LED-service menu" the "sensor values" toggle between "0" an "1". This behaviour can reliably be reproduced.
I've checked all cabling multiple times. I measured the voltage on "sensor pins" (brown, blue, black). I don't have a "white" pin because SuperPinda only has three contacts. I measure on brown pin: It delivers 5v (+), blue pin is 0v (-/ground), black pin toggles between 5v (light out) when triggered with metal and 0v (light on) when untriggered (metal away). There is definitely a 5v signal laying on pin (black) when triggered. This signal is received and shown on the display (0/1).
All mecanical parts are working seamlessly. Stepper motors are movable via menu (up/down, left/right, forward/backward).
The behaviour lets asume that the SuperPinda is not triggering. In fact, appropriate signals are beeing measured. For some reason the signal status is received by the "LED-unit" but obviously not registered/interpreted by the "level-control-mechanism".
Please let me kindly ask for your help! Has anyone an idea what might be wrong? I've ordered an new Pinda Probe (surely a highly desperate action) and I am about to buy a new "mainboard" soon. Environment: Einsy RAMBo 1.2e, FW 3.14.0
Thank you in advance for reading and thinking!
RE: Calibration on i3 MK3s with SuperPINDA fails. SuperPinda is measured and seems to work!!
From your story I understand your conclusion is that the Pinda is not working correct. So let's start there:
- The led on the Pinda goes on/off when approaching iron/metal. Correct?
NB To test, just approach with some metal screwdriver/wrench, it should react to that.
If so, then you know the Pinda is powered the right way and functions (otherwise the led would not go on/off.
Leaves the question if the switched (third) wire of the pinda changes from 0 to + and back when approaching/leaving the metal.
To be checked with a multimeter (as you already did.) . If correct, then the Pinda is OK. From your story I understand this is the situation. So no need to order a new Pinda.
- Does the mainboard/processor see the signals of the Pinda?
In the menu Support > Sensor you can find the status of the Pinda. When approaching/leaving metal it should go from 0 to 1 and vice versa.
If yes, you are ready for next step. (lets communicate on that when you are sure).
If not, then you have to check your cabling (again, and be sure it is all connected to the correct point) Download a layout from the Prusa website to be sure where the wires should go. Also check the connector (measure the values on the board side).
We will do what we have always done. We will find hope in the impossible.
RE:
Hi Eef, hi comunity,
thank you for your reply. I found the solution but not the problem. After replacing the mainboard everything works fine (at least the calibration does not fail although I run into new miracles to be solved later...). The Pinda was not the problem. With the old mainboard I had the default Pinda behavior: Red light "on" when idle (no "metal" sensored), red light "off" when metal sensored. The Pinda information was also handled over to the "LED" display part of the software. The menu item showed "0" for idle "1" for active (metal sensoring). The circumstancial evidence lets asume, we deal with an "additional" control mechanism that is responsible for the Z-axis to be stopped when Pinda says so. But unfortunately this mechanism does not seem to interpret the "LED 0/1" variable nor has the Pinda probe the chance to hand over the concerned values.
In other words: Only because the LED-menu item "probe function 0/1" AND the Pinda control light (on/off) are working fine, does not mean that the "Z-axis control mechanism" is able to avoid Z-axis and appendages crashing on bed.
That's where I gave up. Maybe some hardware developer has the courage to find this design issue - but what can one do against obscure hardware failiure ? -
Thanks everyone for reading and thinking. Hope this helps someone out of desperate situations. Happy printing!