What is the difference between indexer control, and Serial control?

Discussion in 'General Electronics Chat' started by FlightSim12, Jun 21, 2016.

  1. FlightSim12

    Thread Starter New Member

    Jun 21, 2016
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    I am trying to choose a stepper motor controller for a 2 phase unipolar stepper, and I don't want PWM because I have limited PWM outputs on the microcontroller I am using. So I looked around and found stepper motor drivers that are controlled by an indexer and Serial(such as SPI). But I cannot find a satisfactory explanation of indexer control, so I would like to know whether or not the indexer step/dir control pins just work off of plain binary, like a 0 for clockwise and a 1 for counter clockwise, and a 0 for no movement and a 1 for "move one step"? I would also like to know the pros and cons of each control type.
     
  2. Sensacell

    Well-Known Member

    Jun 19, 2012
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    Note that an "indexer" and "driver" are two different beasts entirely.

    A stepper "driver" accepts step and direction inputs- this makes you in charge of handling the (non-trivial) pulse counting and timing tasks required.

    An "indexer" is a device that creates the step and direction signals itself from macro 'move' commands you send it, handling all the messy stuff internally. An indexer typically needs a driver, although some combine both.
     
  3. MaxHeadRoom

    Expert

    Jul 18, 2013
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    A simple indexer uses a pulse chain the rate of which controls the rpm, a separate 1 - or 0 input decides the direction.
    Most drives use this method, the PWM is used for the actual coil switching, the old series resistor method can also be used for non-switched outputs.
    Max.
     
  4. FlightSim12

    Thread Starter New Member

    Jun 21, 2016
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    So that would be the easiest method for controlling multiple steppers with a microcontroller connected to a Stepper motor driver IC that uses the indexer like this chip from TI? http://www.ti.com/product/DRV8805/datasheet
     
  5. MaxHeadRoom

    Expert

    Jul 18, 2013
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    If using pic micro check out the Mechatronics application board link the software is in the link also.
    Max.
     
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