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auto leveling accuracy

Discussion in 'Troubleshooting' started by Lance Weston, Feb 5, 2022.

  1. Lance Weston

    Lance Weston Active Member

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    I have been playing with the new Partsbuilt IR boards and the original Robo boards. What I found is the boards as a group perform about the same with the advantage going to Partsbuilt because the surface mount parts will never shift position. That being said there is variation in accuracy between individual boards, some were excellent and some not really usable. I found that setting the Z feed rate lower from the LCD was the solution. On one machine I had to go down to 3, and I settled on 5 as my standard for the other machines.

    I can postulate that since there is no external crystal on .on the board the micro processor internal frequency reference varies. I would assume the faster the internal frequency the faster the bed rate.


    Well I was totally wrong. Digital means saturated output and Analog means an analog out put. Robo does not use an analog input so we need "Digital" to match the Robo input. The IR board on start up looks for a pullup to Vcc. The problem is that the micro processors have wildly different pullup resistance values and can cause the IR board to come up as analog. The problem with analog output is that the microprocessor input will see the analog on its input as flaky input because the voltages can be right at the 1/0 edge of digital resulting in flaky operation.

    There are two possible solutions: solder a 47k resistor across the two outside pins of the connector. This will force the IR board into digital mode. The other is to program a modified hex code which will only allow the IR board to be in digital mode. I have modified the code and have the hex code.
     
    #1 Lance Weston, Feb 5, 2022
    Last edited: Feb 6, 2022
    mark tomlinson likes this.
  2. Lance Weston

    Lance Weston Active Member

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    If your Robo blinks 2 tiimes on startup you are good to go if 4 times on startup then you are in analog and the IR board must be fixed. I am waiting to get some boards in to test the code change. When the code is verified I will let people PM me and send their board(s) with return postage and I will reprogram the board(s) and return. I will also supply the code for anyone interested.
     
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  3. Lance Weston

    Lance Weston Active Member

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    2 blinks is not enough for good operation, the frequency of the micro must be programmed correctly. I found all of the Robo boards I checked had the same value programmed into the frequency trim in the eeprom. This is a by micro trim. I calibrated the frequency, in the micro, reprogrammed, and now had very good operation. The double blink on power up should be fast, both blinks in about a half second.
     
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