Did I burn up my Xmax Input? :(

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  • April 25, 2015 at 10:34 pm #7662
    bitminer22
    Member

    I got some inductive sensors from work (http://datasheet.octopart.com/BI-1-EG05-AP6X-V1331-TURCK-datasheet-9639722.pdf) which were the NPN type – Bi 1-EG05-AN6X-V1331. They are powered with 30VDC and I wired the output to the switch inputs. It worked well except in the bag was one PNP type which, as best as I can tell, sent 30VDC into the Zmax input, instead of providing it a ground. It doesn’t respond when I manually short it to ground but when I put the PNP switch back, it will trigger not when the switch closes but once it goes open again…

    Does that make sense? Did I break my new TinyG? 🙁

    April 26, 2015 at 7:18 am #7663
    cmcgrath5035
    Moderator

    Each port pin on the tinyG port pin has a 2.7k small chip resistor(a pull-up)to +3.3v and a 0.22uf cap to ground.

    applying 30 V to the port pin likely damaged the input structure on the IC as well as flowing back thru the 2.7K into the 3.3V bus.

    Schematics are here if you want to look

    Your description implies tinyG still communicating?
    I am somewhat amazed.
    I for sure would not keep testing with the 30V connection to the PNP .

    Do you have your port pins properly set to NO in tinyG parameter?
    A high current surge may have damaged the sensor as well ?

    April 26, 2015 at 11:07 am #7664
    bitminer22
    Member

    Yea I’ve looked through the schematics but I’m not great with those. The weird thing is all the other inputs work, and yes, the Xmax still “works” just ONLY with the PNP switch and it only triggers after the switch is released, not when the contact is first made. BUT if I try just connecting a wire from ground to Xmax; nothing. Doesn’t trigger at all. It’s like it got used to +30v and now won’t work with anything else…

    Is there a way to use the A axis inputs for as the Z axis? I won’t need the A for quite some time and could make this work for now if I could.

    April 26, 2015 at 3:31 pm #7665
    cmcgrath5035
    Moderator

    Strange indeed that the damage is as you describe.

    Is there a way to use the A axis inputs for as the Z axis? I won’t need the A for quite some time and could make this work for now if I could.

    Likely you could frog thw A pins and X pins by modifying and recompiling the code, although I have not looked at the code so cant recommend a whole lot. You’ll have to wander thru the code base – perhaps someone who has done this will stop by.I would start by trying to understand file hardware.h and how it interacts with the interface processing.

    Be aware that the damage to the chip caused by this might ‘grow’ over time, say if the top level insulating layers were cracked by the sudden burst of heat. So have a backup plan in mind as you move forward.

    April 27, 2015 at 5:04 pm #7666
    bitminer22
    Member

    I just had a thought – and I’m kind of embarrassed it took me this long to think of – but one of the businesses I have a relationship with is an electronics and motor assembly shop! That means I could just have them replace the ATxMega chip with all their fancy reflow, pick and place type stuff! I showed the boss a picture of the board and he said yea, no problem!

    The chip is $10-ish on digikey. I’m going to check the resistor and capacitor for that input tonight to make sure they aren’t the culprit and that’s the only other path to ground I can find.

    Any reason this wouldn’t work? Is the firmware stored on the ATxMega chip or somewhere else? Will a new chip just be plug ‘n play?

    April 27, 2015 at 6:59 pm #7667
    cmcgrath5035
    Moderator

    Yes, flash is on-board the xMega.
    However, a factory fresh tinyG has the bootloader installed in a protected area of flash. The boot loader would need to be loaded with an Atmel ICE or equivalent.
    Here is a good starting point for navigating the process; I have never tried this myself.

    April 27, 2015 at 8:11 pm #7668
    bitminer22
    Member

    Sigh…

    Well at least they are only about $35. In fact, I wonder if the same company has one I can borrow… 🙂

    On a side note, when I was playing with my limit switches, they would stop the axis when it hit the limit (input goes… low?) but then I’d reset and jog away and it would trip again when the switch turned off and the signal went the other way. Then I’d have to reset again. Is that normal or is there a setting I’m missing? There’s a ton of settings like this in the homing section but are there separate ones for limit switches?

    Thanks for all your help!

    April 28, 2015 at 4:08 pm #7669
    cmcgrath5035
    Moderator

    Limit switch recovery – limit switches act like a non-maskable interrupt that stops the tinyG process cold, position info, etc are lost.
    The results of the reset are to set machine zero where ever thew machine is.
    If the switch is still operated (closed for a NO), then any attempt to move with jog or Gcode command will trip limit again.

    Solution 1 – manually move the machine away from the limit
    Solution 2 – if manual is not practical, after reset turn off limit switches, then jog/move away from current location.Re-enable limit switches

    • This reply was modified 9 years, 6 months ago by cmcgrath5035.
    April 28, 2015 at 8:40 pm #7671
    bitminer22
    Member

    Gotcha, thanks. Manual moving is not really easily done but I’ll look at the other option. It’s not a huge deal to reset twice – I just wanted to make sure I wasn’t missing something easy.

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