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Question Sabertooth 2x32 & Uno Rev3

Discussion in 'Electronic and hardware generally' started by Deane, Sep 7, 2018.

  1. Deane

    Deane Old Fart

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    My Motion Simulator:
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    I am still struggling with the electronics on my 2DOF build.
    My motors arrived and know I need to order the brains of the system.

    So I have decided that a Sabertooth 2x32 Controller will best suit my motors which are the 50:1 versions of https://www.motiondynamics.com.au/worm-drive-motor-12v-24v-200w-180-rpm-20nm-torque.html
    but I am a little confused as to why it recommends using a battery in parallel with an suitable size power supply such as a Meanwell or an couple of HP Server power supplies.

    Is that correct or did I misinterpret the whole thing ?
    The other part that I know I must use with the Sabertooth is an Arduino Uno Rev 3 but again I see that there are many different versions or knock- offs at half the price and a developers Uno Rev 3.
    So am I on the right track with this one https://www.littlebirdelectronics.com.au/arduino-uno-r3 please ?

    Electrickery. Give me a welder anyday :sos:sos:sos
  2. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator

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    The Sabertooth 2x32 can be used with a PSU, but the 2x60 needs batteries to deal with regenerative current:

    [​IMG]
  3. Deane

    Deane Old Fart

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    So presumably the two PSU's that I ordered from Fleabay which are 12V 30A 360W should do the trick.

    After some more reading of build threads and people's bad luck with pot's durability I am opting for the Hall Sensor method and ordered some of the same SENSOR HALL 0.2V +20V TO -10V PIN - 6127V1A180L.5FS (Fnl) :eek:
  4. FoxHound.92

    FoxHound.92 2DOF seat mover

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    Has anyone already used clamp resistors instead of a paralell battery with the sabertooth? Or does the sabertooth 2x32 not need a battery?
  5. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator

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    As per the description for the 2x32 you do not need to use a battery to deal with regenerative current.
    • Agree Agree x 1
  6. FoxHound.92

    FoxHound.92 2DOF seat mover

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    That's what I made of it. Was double checking because it is also stated at least one should be used.
  7. Peacemaker105

    Peacemaker105 Member Gold Contributor

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    My question is, are the supplied 10w, 5 ohm resistors supplied big enough to handle max working load? my electrical knowledge is limited in this area. I bought 100w 1 ohm ones off ebay before i realised they supplied some in the box haha. I have 24v 450w motors. I was just going to use what came in the box but the picture above shows them doubling up on each side with extra resistors.. so 4 per 2x32 instead of 2 which is supplied or would my 100w 1 ohm ones work better/safer? 10w per channel doesnt sound big enough for the power i'll be runnning, but then again i dont fully understand how they work, maybe 10w is enough to save your PSU?
  8. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator

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    My Motion Simulator:
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    See the resistor calculator here: https://www.dimensionengineering.com/calculators/power-resistor

    And the Sabertooth manual here: https://www.dimensionengineering.com/datasheets/Sabertooth2x32.pdf
    Last edited: Nov 17, 2018
  9. Peacemaker105

    Peacemaker105 Member Gold Contributor

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  10. ilbiga

    ilbiga Active Member

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  11. Pino Pistolidas

    Pino Pistolidas New Member Gold Contributor

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    I also had some difficulties understanding which resistors to use. I contacted Dimmension Engineering and as I understand it know:

    You are using 450W motors at 24 volts which comes to 18.75A
    The maximum current de Sabertooth 2x32 can disapate is 8A, so this is the value you have to use in your case.
    So 8A x 24V = 192W which you can disapate per side (P1 and P2) so in total 384W, please correct me if I'm wrong.
    And the resistor you would need per side is 24V / 8A = 3 Ohms which can handle at least the 192W so lets say 200W.

    The 200W resistors are expensive and not so available. So you can either use 2 x 1.5 Ohms 100W reistors in series per side.
    Or 2 x 6 Ohms 100W in parallel per side.

    The last one is also what I'm going to try I ordered 4 of the 6 Ohms 100W resistors from Aliexpress, which will arrive next week.