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Stepper on the PDB — Parallax Forums

Stepper on the PDB

NewzedNewzed Posts: 2,503
edited 2005-06-29 01:54 in BASIC Stamp
I'm trying to connect my unipolar stepper to my PDB, using Jon's N&C Column 121 - The Parallax Professional Development Board.· The inputs to the L293 are labelled 0-1-2-3 but I am taking that as Ph. 1, Ph. 2, Ph. 3 and Ph. 4.· I want to run the stepper with an 18VDC power supply.
Would I be correct in hooking both the unipolar common and the 18VDC positive to the V+ terminal on the L293, with the 18VDC negative going to the Gnd terminal, or, should the common and positive 18VDC be connected together on the breadboard, ignoring the V+ terminal?· Both Enables will be pulled high.

This is the first time I've used the L293 module and I would rather not burn it up.

Thanks

Sid

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-06-28 22:45
    Sid,

    ·· There is a wiring diagram in the documentation for the PDB showing the connections on the L293D.· You will need to connect your 18V supply to the V+ pin along with the common from the Stepper.· I don't know what you mean about going to the breadboard, but I would keep that voltage isolated and away from the breadboard myself.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • NewzedNewzed Posts: 2,503
    edited 2005-06-28 22:51
    Chris, I have looked at all the docs as well as the schematics in Jon's column.· My question was with a unipolar, do I connect both the unipolar common and the 18VDC to the V+ terminal.· It occurred to me that the L293 module should be used only for bipolar and not unipolar.



    Sid
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-06-28 22:58
    Sid,

    ·· The L293D will work with both Unipolar and Bipolar Stepper Motors.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • NewzedNewzed Posts: 2,503
    edited 2005-06-28 23:08
    Good.· Then back to my original question - do I connect the unipolar common and the 18VDC together at the V+ terminal?

    Sid
  • dandreaedandreae Posts: 1,375
    edited 2005-06-28 23:12
    Yes Sid, you are correct.· You connect the common from the stepper and the positive lead of the power supply to V+ on the PDB.



    Dave

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    Dave Andreae

    Tech Support
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    Http://www.parallax.com

    ·
  • NewzedNewzed Posts: 2,503
    edited 2005-06-28 23:19
    Thanks, Dan.· In looking at the PDB schematic I see the the V+ terminal goes to pin 8 on the L293, but I don't know where it goes inside the L293.
    I was afraid I might be applying 18VDC to both ends of the windings.· I'll give it a shot and see what happens.

    Sid
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-06-29 01:54
    Newzed said...
    Good.· Then back to my original question - do I connect the unipolar common and the 18VDC together at the V+ terminal?
    Sid

    Sid,

    ·· That was answered in my first reply.· See below:
    Chris Savage said...(trimmed)
    You will need to connect your 18V supply to the V+ pin along with the common from the Stepper.


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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
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