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I Accidentally Did It - V+ to Ground

Discussion in 'Controller Boards' started by Tim Waldvogel, Mar 8, 2022.

  1. Tim Waldvogel

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    PROBLEM: Well, guys against the advice of my manual, I touched v+ to ground accidentally while troubleshooting setting up my inductive limit switches.

    WHY: I had them wired correctly, I had the blackbox set to the 24v v+ setting and was getting the red light on the inductive switches switching off when I touched metal objects to the tip as expected. I was looking at the Troubleshooting screen and trying to determine why the status indicator on the software was not changing when I would trigger the inductive switch. In a tired (bad judgement) moment, I pulled out the wires from my phoenix connector for an unknown reason at the moment and touched v+ to ground. I saw a spark and smelled that glorious smell when something isnt right.

    THE BIG QUESTION: I turned off the controller and moved the jumper back to the 5v position and plugged in a single xtension limit switch that came with my kit. It is triggering successfully in the software. What did I fry? my first inkling was I touched the signal wire to v+ and fried a part of the microcontroller or something. Is there a voltage regulator or something I damaged? All motors are moving successfully, I can still connect to the controller. The spindle turns on and off.

    MY CURRENT SOLUTION: I think I am gonna go on and order another Blackbox on the credit card. Sometimes you just get too excited and make hasty decisions. I dont trust the one I have now after that smell. Maybe its somehow repairable with my reflow gun, but I do not know enough about the black box to know

    Random fact, after moving the jump, 2 of the 3 inductive switches were still plugged in and now had lights again (even though its supposed to be 6v minimum) they would trigger the light, but not the software still on the 5v setting.

    Any input that isnt shaming me for making a bad decision is welcome. I am also accepting donations and discount codes :p (jk)

    upload_2022-3-7_22-59-23.png
     
  2. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
    Staff Member Moderator Builder Resident Builder

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    If you have one of the newer V2.9s, v2.10s etc its a little more "userproofed" and might just be fine. If all still works.
    Having the Jumper on 24v probably saved you some more damage too (thats just direct off the PSU, shouldn't affect regulators, mcu, etc)

    Regarding seeing the signal on the Troubleshooting tab: make sure you have NPN inductives, not PNP.
     
  3. Tim Waldvogel

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    I do have PNP normally closed indicatives as those are usually the safe bet. (From what I have read), after frying my board someone mentioned that changing $5 in GRBL settings should invert what it expects to see. Is this not the case? Are PNP’s not useable?

    As for my blackbox, it’s like 3 years old or so, so I am not sure what version that one is. I ordered an additional black box and will probably just troubleshoot it on my electronics bench later or keep the muscle board as a spare just in case.
     
  4. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    BlackBox needs NPN (active low). The inputs are protected against high voltages
    Grbl's invert setting does not really apply here, its in terms of the signal levelling - PNP's go from High-Z to HIGH when triggered, BlackBox's EMI filter has pullups and is thus high all the time too.

    NPNs pull the pull-ups down to GND allowing the controller to see the change.

    Grbl's invert is "switch signal is in triggered state only when the switches are hit" vs "signal is in triggered state all the time and 'untriggers' when the switches are hit" - signifying the difference between NO vs NC.

    That would be an older version then
     
  5. Tim Waldvogel

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    I appreciate the information on the endstops. That is likely a contributing factor and I’ll need to order some NPN ones, it’s very helpful.

    Given my symptoms and my intent to prepare better as my new black box ships . It’s probably safe to say since everything else still works my PSU is still safe (I’m not using a MeanWell, but rather another high amp output PSU I bought for a abandoned 3D printer project).

    I value your input here. I posted the link below if it matters or if you’re curious.

    ABI 24V 500W Power Supply Indoor Outdoor LED Driver Rainproof Weatherproof 21A https://www.amazon.com/dp/B01IU8QBCO/ref=cm_sw_r_cp_api_glt_i_0YREZWYV17W2APY4XWN5?_encoding=UTF8&psc=1
     

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