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SFX-100 Actuator Homing & Calibrating

Discussion in 'Motor actuators and drivers' started by ERGUN OZYURT, Sep 7, 2020.

  1. ERGUN OZYURT

    ERGUN OZYURT erguno

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    Hi everybody,

    I am looking sfx-100 actuator design, but I can not find any limit switches etc for homing & calibrating. How sfx-100 find home position ? I know servos are intelligent but they need absolute positioning for range if they dont have absolute encoder ?

    Any knowledge ?

    Thanks.
  2. morpwr

    morpwr New Member Gold Contributor

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    If you use the Thanos controller it has protection built in for that. He has videos showing how it works. Ive been using his for a few weeks now and it works great.
    • Agree Agree x 1
  3. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

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    Be careful with servomotor. If not using proper controller, you might face a few unexpected problems or failures down the road, that you should be prepared for. See here on this video where I force for the sake of documentation some common failures and how the protections kick in to prevent damage.

  4. ERGUN OZYURT

    ERGUN OZYURT erguno

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    Thanks for explanation. But I want to know how this technically can be done ? I am not talking about protection. You may get alarm from servo controller and stop simulator.

    But in normal conditions, while you are using your simulator, electric goes down. Controller and no body knows position of any actuator. After electric come again, how it can determine last positions of actuators ?
  5. wingert

    wingert Active Member

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    the weight of the rig pushes the actuator with no motor power always to the lower starting position
  6. ERGUN OZYURT

    ERGUN OZYURT erguno

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    I did not tested it yet, but as I read about ball screws, there is a lock to for linear motion without spinning, like gearboxes. If there is a lock, rig should not move with weight. If there is no lock, holding torque of servos should be enough for holding rigs when no motion.
  7. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

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    In any case you need to calibrate the home position of the actuator EVERY time you enable the servo, even with worm gear. And with leadscrew you still may not 100 confident that all actuators are really lowered down to 0 position by gravity...

    You can even use external contactless limit switches if you don't want to try the motor against hard stop (if not available for example):

    • Like Like x 1
  8. wingert

    wingert Active Member

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    Not in this concept, e.g. if you push the E-stop the rig moves immediately down.
  9. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

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    Correct... The AMC-AASD15A controller however has hold mode e-stop as well... it will hold position of the motors even if not equipped with brakes ;)

    Have another look in the video: