grblshield fried?

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atrueresistance
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grblshield fried?

Post by atrueresistance » Tue Jan 27, 2015 6:57 pm

Hello, I'm looking for some help to determine what could possibly be wrong with my grblshield. How to test probe to find any bad parts?

I was reassembling the machine after upgrading to 1,000mm x 1,000mm. X and Y were connected incorrectly. Z direction inversed. I know this because the GRBLShield was working and motors were turning. I also wanted to get spindle control setup, so I soldered up a solid state relay in a junction box to control an outlet for on/off where the DW660 is plugged in. Confirmed working with linthium ion battery (3.7v) to trip ssr. Functions as expected. Connected negative to grblshield ground and positive to pin 11. No M3, M4, M5 with combination of Sxxx commands tripped the ssr. Assuming this is because I had flashed .09 with Shapeoko 2 pre compiled listed on grbl's github. So after giving up, I disconnected the ssr wires, and went to swap X and Y. After swapping, and replugging the shield in is when the problem started.

Without the shield on the arduino grbl .9 shows under COM4 and connects, however when connecting the shield no COM ports are shown. The arduino does not loop or boot correctly(do not know the proper term for this aka lights don't blink as they would if functioning normally). I disconnected all wires from grblshield and the problem still persists.
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Caesar S
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Re: grblshield fried?

Post by Caesar S » Tue Jan 27, 2015 8:42 pm

Disconnecting the stepper motor driver from the gshield is not a good idea. When motor commands are issued, the motor driver could be fried without the stepper motor connected.

I would, disconnect the motor power supply from the gshield to prevent that from happening. If you have gshield in an enclosure, take the arduino uno and gshield out so you can better see the pins going where. Separate the gshield from arduino

The arduino seems fine as you can get to grbl and use the $$.

Power everything down, disconnect the USB cable from arduino (the USB provides +5VDC power to arduino).

Insert the gshield pins into arduino, check to be sure that they are in alignment.

Power up ONLY the arduino, and see if it behaves properly. if so, then connect the stepper motors to the gshield.

When connecting the stepper motors, make sure all of the wires are connected, you can use a multimeter to test the stepper motor continuity before connecting them to the gshield.

You can also use a multimeter to test continuity from the gshield connector screws to the stepper motors.

Once all that you power up the stepper motors, and test it out.

If the stepper motors make a growling sound, it's a loose connection.

Hope this helps.

atrueresistance
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Re: grblshield fried?

Post by atrueresistance » Tue Jan 27, 2015 9:20 pm

Caesar S wrote: Power up ONLY the arduino, and see if it behaves properly.
Power only to arduino outputs grbl greeting. grbl commands send response. Arduino registers as COM4

Caesar S wrote: Insert the gshield pins into arduino, check to be sure that they are in alignment.
With arduino disconnected, I connect the gshield to the arduino checking pin alignment. Then plug into usb and only usb. No COM port shows up.
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cvoinescu
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Re: grblshield fried?

Post by cvoinescu » Tue Jan 27, 2015 9:27 pm

That sounds like your gShield is toast...
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atrueresistance
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Re: grblshield fried?

Post by atrueresistance » Tue Jan 27, 2015 10:20 pm

Where should I start for testing the board components? How would a person test to find out exactly which component failed?
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cvoinescu
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Re: grblshield fried?

Post by cvoinescu » Wed Jan 28, 2015 11:52 am

It's very hard to communicate the answer to that, because there are many things to try, and not all outcomes are clear indications of what's wrong, some are just hints. Designing a failure analysis tree is a complex art.

But, to get you started: if the Arduino doesn't work with the gShield on, it means the gShield is doing something to a feature of the Arduino involved in communicating with the PC. The only thing I can think of is power. D0 and D1 (serial Rx and Tx) are also required for communication, but aren't wired on the gShield at all. RESET is required to be high for the Arduino to work, but that's not connected to anything that can go bad on the gShield either. So the only possibility is that one of the drivers on the gShield is broken in such a way that it shorts the logic power to ground. A capacitor could also be short-circuited, but that would be unusual. It's much more common for ICs to die that way. I'm not sure how you'd tell which one of the three was bad, except that there's a chance that the bad one is so deeply fried that it will measure different voltage drops or reistances on its logic inputs (STEP, DIR) with respect to GND or +5 V. Measure this with the gShield completely disconnected from everything, using the diode test range of your multimeter.
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atrueresistance
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Re: grblshield fried?

Post by atrueresistance » Tue Feb 03, 2015 6:51 pm

Thanks for the help. Just to be certain I don't fry the new one showing up today. . .

Arduino Firmware is Grbl v0.9g Atmega328p 16mhz 115200baud with ShapeOko2 defaults (2014-09-05) Does this come with PWM enabled by default?

I have a SSR 10a much like this. Fotek 10a

Thought Process if PWM is enabled
  • Connect pin 11 to + 3-32V DC SSR.
    Connect pin ground to - 3-32V DC SSR.

    With X, Y Z motors all connected. Hook up power and connect.

    Send

    Code: Select all

    M3
    Send

    Code: Select all

    S255
    set to max speed? 5V

    The SSR should trip turning on spindle.

    Send

    Code: Select all

    M5
    to kill spindle.

    I'm trying to get ready for Laser Ink, and still being able to turn on/off spindle.
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cvoinescu
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Re: grblshield fried?

Post by cvoinescu » Tue Feb 03, 2015 8:11 pm

AFAIK, that build of GRBL does not have PWM enabled. Without PWM, you can get the relay to turn the spindle on and off if you wire the +3-32V to IOREF (or +5V) on the Arduino, and -3-32V to to D12. With PWM, what you said (relay + to D11, relay - to GND).
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