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Stepper Control Without HSO Card

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  • Stepper Control Without HSO Card

    Hello All,

    I have a machine I am designing that utilizes 6 different stepper motors for different motions. I Currently have a Productivity 2000 plc with the HSO card and have been able to operate two of these motors this way. Each motor (stp-mtr-23079) is hooked to a stp-drv-6575 drive and work properly when I set the drive into test mode.

    What I would like to do is get away from buying two more HSO cards/ziplink components to save some cost since this is a prototype. I know that my drives have three inputs step/direction/enable to control them. Would it be possible to hook this card up to a analog or discrete output card to control the motors? These four motors that are not hooked up to the HSO only need to spin in one direction, and I am not concerned with how many steps they are taking at this time. If I figured correctly the plc refresh rate is 2000 refreshes/second and if I set my drives to 200 pulses per revolution this would give me 20 rpm's roughly, which is more than enough for this application (at this moment at least).

    If it is possible could someone give me a brief explanation on how to wire and program to make this work? I believe that i will need to buy a discrete output card like the P2-08TD1P card for this to work.

    Thanks Everyone,


  • #2
    You could use a regular digital output for step. That is the most critical signal, however you say 200 pulses per second, that is one pulse each 4ms. Motors wonít increment as smooth but they will maintain phase ( will move in synchronized) and I donít think youíll detect any jitter. For testing, it should be good enough. Also because is testing , you could maybe decrease the speed further, if need be.

    as for the other two consents- direction and enable, you could use a relay output to set same direction on multiple motors. Enable is a bit more important, cause you need to disable each motor individually.

    you could also try to find a pulse generator controlled by analogue signal.


    • #3
      The standard drives like the stp-drv-6575 dont seem to have analog input, so you wont be able to use an analog card to them.

      output of the regular discrete outputs may be fast enough to do some really basic movement in one direction, but as Alexandru said it likely wont be as smooth a movement as with the HSO.
      The stepper drives may want 5v input and the discrete outputs do 12-24v. If they are 5v input only you will need to use a resistor on each output you use to drop the voltage down. I dont remember the value they tell you for 12->5, but I believe the 24->5 is 2.2kohm.