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stepper motor problems

$WMc%$WMc% Posts: 1,884
edited 2009-01-17 08:29 in General Discussion
Hello All

I have salvaged some stepper motors from a junk lexmark printer/fax.the motor is a Mitsumi p#M42SP-4Nk
My problem is that it only has 4 wires and not 5 like the M42SP-5"The motor sent w/ the Pro.Dev.Board"

I'm using the on board L293DNE stepper driver.This works with M42SP-5 but not with M42SP-4NK
I've rolled the wires around like the StampWorks Manuel suggests, But all it does is vibrate then shut off?

One other thing·I found is the stepper that works is 100ohm and the 4 wire stepper is only 5ohm

I have another stepper its a AIRPAX 60ohm 7.5deg/step motor, it has 6 wires.this motor looks like 2 motors back to back theres a·"black,·yellow, and white"coming from each motor half. I have tried wiring it a few different ways,·But all it does is vibrate.?

the M42SP-4NK has an Orange,Blue,Yellow,and Red wires.
the AIRPAX has 2Yellow,2Black,and 2White wires

Any help from some·of·You·stepper Pro's would be Greatly App.!

_______________$WMc%________

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The Truth is out there·········································· E=$WMc%2

Comments

  • FranklinFranklin Posts: 4,747
    edited 2009-01-11 20:35
    Most 4 wire steppers have a wire on each end of a winding with two windings in the motor. Use a meter to find out which two wires go to each coil. There are plenty of info on 4 wire steppers out there. It looks like the one you salvaged needs 21V minimum to work...

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    - Stephen

    Post Edited (Franklin) : 1/11/2009 8:43:09 PM GMT
  • $WMc%$WMc% Posts: 1,884
    edited 2009-01-11 21:10
    Franklin

    I double checked the coils. Orange and Blue are one coil and Yellow and Red are the other.If I help the stepper it turns but its erratic.
    It runs kinda but then stops. I assume this is the thermal shut down thats stopping the motor?

    Do I need to change the step sequence or is the low 5ohm coils the problem?

    %1100
    %0110
    %0011
    %1001

    Could this 4 wire stepper be a "bipolar" stepper and I'm trying to run it as a unipolar stepper?

    ____________$WMc%___________

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    The Truth is out there·········································· E=$WMc%2
  • SRLMSRLM Posts: 5,045
    edited 2009-01-11 21:19
    You can run most stepper motors (up to six wires?) with the same code and driver. The only difference is that way that you set them up. That said, take a look on the parallax stepper motor product page and the N&V article "Stepping Out With Spin". It's for the propeller, but it discusses in depth the BS2 code too.
  • $WMc%$WMc% Posts: 1,884
    edited 2009-01-11 21:52
    SRLM

    Thanks for the link. I looked thought the "Product page" But I guess I missed it. I'll run a google search for "Stepping out with Spin".I did find some useful info on the way.

    Thanks again for the link.

    _________________$WMc%_________

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  • $WMc%$WMc% Posts: 1,884
    edited 2009-01-12 00:57
    OK

    I found the "Stepping out with Spin" as it turned out I did need to change the Step sequence. from
    %1100
    %0110
    %0011
    %1001

    to

    %0011
    %0110
    %1100
    %1001

    I ran this code but had the same problem, Just vibrates. I then realized that I grabbed the small 300ma wall wart cord for the Propeller and not the 1 amp wall wart cord for the BS2.after the swap; The stepper will run now but it has HI-indentions or is not smooth running "It jerks from one step to another" I think this is due to the low ohm coils

    Should I add some hardware to the driver output or is their a better way to drive these low ohm steppers???

    __________$WMc%________

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    The Truth is out there·········································· E=$WMc%2
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2009-01-12 01:02
    "The stepper will run now but it has HI-indentions or is not smooth running "It jerks from one step to another"

    I think you need to look into half-step mode. *


    By the way,
    · %1100
    · %0110
    · %0011
    · %1001
    is the same as
    · %0011
    · %0110
    · %1100
    · %1001
    they'd result opposite directions.

    * Depending on the deg/step.

  • PJAllenPJAllen Banned Posts: 5,065
    edited 2009-01-12 01:10
    Here's half-step.· It has less torque, but smoother travel:

    ·1 2 3 4

    ·x
    ·x···· x
    ······ x
    ···· x x
    ···· x
    ·· x x
    ·· x
    ·x x
  • $WMc%$WMc% Posts: 1,884
    edited 2009-01-12 01:49
    Mr PJ Allen

    I think Your on to something here. A purpose built half step motor...!! This would explain A lot.

    I'll modify the code to Your spec and see if it works out.

    Many Thanks

    ____________$WMc%________

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    The Truth is out there·········································· E=$WMc%2
  • willy1067willy1067 Posts: 107
    edited 2009-01-12 03:15
    see if one of my old project helps

    http://forums.parallax.com/showthread.php?p=641371

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    Fernando Gomez


    ·http://pinellas-sign-manufacturer.com

    Never compare yourself with anyone else, there will always be someone bigger·or·smaller·than you.
  • John BondJohn Bond Posts: 369
    edited 2009-01-12 11:25
    I rip steppers out of old photocopiers. I occasionally have problems with 4 wire bipolar motors. As you already know, you drive them with an H-Bridge circuit rather than an open collector circuit.

    1. Check to see if you haven’t blown one half of one of the H-Bridge driver circuits. (you’ve already checked the motor so that’s OK)

    2. Draw yourself a truth table to check the coil windings. Sometimes they are:
    1010
    0110
    0101
    1001
    You can either change the wiring or rewrite the table. I tend to do it in software

    I always remind myself when I am battling with a stepper motor that there are just 3 areas where you can have problems.
    • The driver circuit is blown (or incorrectly wired) – check the voltage across a coil using a multimeter (you usually slow the step speed down to 500ms or even 1 second). You should see step 1 = +12V , 2 = 0V, 3 = -12V , 4= 0V then repeat…
    • Insufficient current to the coil (either too low a voltage or driver circuit can’t handle the Amps) – Check the amps supplied from the power supply using a meter.
    • The device isn’t getting the right signal – You’ll usually pick this up in the first check above, If not, draw yourself a truth table.

    I try to use an existing driver circuit and a piece of code I know works when testing a new motor

    I hope this helps
    John Bond

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  • $WMc%$WMc% Posts: 1,884
    edited 2009-01-13 00:58
    Mr PJ Allen

    I tried Your suggested half step approach. the low 5ohm stepper just vibrates? I hooked the 100ohm stepper and it ran fine with the half step. I have a few more junk printers that I can rob the steppers out of,Maybe this one is bad?

    Mr. Willy1067; I looked at Your driver and I like it. I have dug up enough parts to make it from My on hand stash, I'll try to put it together tonight and see how it does.

    Mr J. Bond; I checked the voltage,s on the step output of the L293 they looked good. I used the "MIN/MAX" on My Fluke 87V to read this. I blew the 44/100th fuse a week or to ago so I can't check current tonight.

    _________I Thank You All for the Replys..._______$WMc%____

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    The Truth is out there·········································· E=$WMc%2
  • John BondJohn Bond Posts: 369
    edited 2009-01-13 14:32
    Hi $Mc%

    Some devices can be very frustrating - Just relax and take a long slow breath...

    Then start again from the beginning and follow the debugging steps, right from the start.

    Is the Stepper motor OK
    - Recheck the leads to ensure there isn't a short between coils. (write down the stepper truth table while you're at it)

    Are the individual coils being switched (unplug the stepper, slow down the switching speed to 500ms and use your multimeter)
    - Is a driver circuit blown.
    - does each coil switch positive, off, negative, off. (your circuit truth table may look something like this)

    1 2 3 4· ·<- Coil connection No
    ______________
    + - 0 0 <- Step 1 - Coil between 1 and 2 powered
    0 0 + - <- Step 2 - Coil between 3 and 4 powered
    - + 0 0 <- Step 3 - Coil between 1 and 2 powered
    0 0 - + <- Step 4 - Coil between 3 and 4 powered
    + - 0 0 <- Step 5 - Coil between 1 and 2 powered

    Are they switching in the correct order (does the truth table for the stepper and the circuit match?)
    - (I usually skip the truth table, I have both tables in my data section so I quickly try the one, if it doesn't work I try the other. This can blow your driver circuit so a truth table is safer)

    If you'v done the steps above and it still doesn't work
    - Measure the voltage comming in to see that you have enough juice. Too much amps draw will cause the volts to dip.
    - Place a debug line at the top of your program to see if the Stamp keeps resetting (due to brownout)

    If you get this far and it still doesn't work, in all probability you've missed a step so just run through it again. Yes it seems frustrating but the first is usually the most difficult and it's worth the effort. I just love seeing all those little (and not so little) motors wizz and whirl.

    Kind regards from Kwa Dukuza, lost somewhere deep in the the Dark Continent of Africa
    John Bond

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  • Beau SchwabeBeau Schwabe Posts: 6,568
    edited 2009-01-13 18:29
    $WMc%,

    I agree with John Bond, it sounds like the polarity and or sequence is not being switched properly.
    Another possibility is that the 5 Ohm stepper requires more current/voltage at the speed you are trying to drive it at than your supply can deliver. Try slowing down the sequence and see if that helps, at least to make sure that your sequence is correct.
    I have an 8-wire (4-coil with all leads brought out) stepper that measures 11.5 Ohms. In a unipolar configuration, the stepper shows similar characteristics compared to a 100 Ohm stepper motor I also have. Increasing the voltage/current drive to the 11.5 Ohm stepper and/or reducing the initial speed before ramping the speed up on the stepper helps.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Beau Schwabe

    IC Layout Engineer
    Parallax, Inc.
  • $WMc%$WMc% Posts: 1,884
    edited 2009-01-14 03:56
    Mr.Bond And Mr.Schwabe

    I thank You for Your replys

    I think it is possible that I'm not hooking this 5ohm stepper up write! This is what I have
    orange 1
    blue 2
    yellow 3
    red 4

    from orange to blue=5ohms, from orange to yellow=OL, from orange to red=OL
    from blue to orange=5ohms,from blue to yellow=OL,from blue to red=OL
    from yellow to orange=OL, from yellow to blue=OL,from yellow to red=5ohms
    from red to orange=OL, from red to blue=OL, from red to yellow=5ohms

    Am I missing something here? Confused!

    If I swap the 100ohm stepper in place of the 5 ohm stepper,it runs fine, full step or half step.

    I've down loaded the specs on the L293DNE and I don't see any real limitations on coil ohm impedance?

    _________$WMc%___________Thanks again for the help

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    The Truth is out there·········································· E=$WMc%2
  • Beau SchwabeBeau Schwabe Posts: 6,568
    edited 2009-01-14 04:56
    $WMc%,

    I believe you have a unifilar stepper motor or a two phase motor...

    http://www.hobbyprojects.com/stepper_motors/unifilar_motor_winding.html

    ...try the diagram in the attached datasheet, starting with page 7...




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    Beau Schwabe

    IC Layout Engineer
    Parallax, Inc.
    pdf
    pdf
    L293D.pdf
    496K
  • $WMc%$WMc% Posts: 1,884
    edited 2009-01-15 03:08
    Mr.Schwabe

    Thanks for the link. as My download was only 5 pages long from Mouser.

    I see that theirs only two inputs from the Stamp. Do You know if the two pairs of input NOTs are internal or do I need to add them.I didn't see any *notes on this like the EMF diodes.I'm still not sure what kind of stepper I have?

    The motor clearly says STEPPING MOTOR on the little white sticker along with MITSUMI and Part # M42SP-4NK.

    I'll run another search for this stepper, And maybe find out just what kind of stepper it really is.

    Mr.J Bond··· I missed the step layout on My first read of Your post reply,But on the second scan I see it is different than the steps I'm using.· I'm a little confused with +-00 as I see "0" as low or Hi and "1" the·opposite with respect to ground. I feel that I'm missing something important here!

    _____Thanks for the reply______$WMc%_________

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    The Truth is out there·········································· E=$WMc%2

    Post Edited ($WMc%) : 1/15/2009 3:26:49 AM GMT
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2009-01-15 03:25
    http://www.mitsumi.co.jp/Catalog/compo/motor/m42sp4_e.html
    http://www.mitsumi.co.jp/Catalog/pdf/motor_m42sp_4_e.pdf
  • $WMc%$WMc% Posts: 1,884
    edited 2009-01-15 03:36
    Mr. PJ Allen

    Thanks for the link.

    I see I need a lot more voltage.Not sure about the step angle?

    _____________$WMc%_______

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    The Truth is out there·········································· E=$WMc%2
  • John BondJohn Bond Posts: 369
    edited 2009-01-15 09:59
    Hi $WMc%

    We are not talking binary numbering, we're looking at the electronics. The 0 refers to no connection, the + refers to switched to the positive rail and the - is switched to negative rail. The driver circuit has three states (not two) on each connection to the coils, what they are sometimes refered to as 1, 0 and Z (HiZ) but don't let this confuse you. just see the circuit is connecting the coils to the positive then then off then the negative power rails then off in the right order.

    Do this by checking each connection to the stepper motor. Does it switch +XX.Xvolts, 0volts, -XX.Xvolts, 0volts, +XX.Xvolts, 0Volts, -XX.Xvolts and so on. (XX.XXvolts is the voltage on the power rail less the very small drop caused by your driver circuit). Take the first connection. Does this switch according to the table. Then the second connection, then the third...

    Just do it and see what results you get, write them down and lets see what they are.

    John Bond

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  • $WMc%$WMc% Posts: 1,884
    edited 2009-01-16 02:03
    Mr. J Bond

    I checked the voltages and they·are toggling, But I can't confirm the order with only one DVM. I'm reading the output from the L293DNE witch is ~13 volts +/- . I slowed the step rate way down to read this.

    I have an Idea to use 4 red LEDs and 4 green LEDs to give a visual on the output "POS.=red NEG.= green no lite led= HIz" I'll get back to this post when I complete it and have some results.hopefully Friday night or Sat.


    ___Thanks for the replys and the help____________________$WMc%__________

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    The Truth is out there·········································· E=$WMc%2
  • $WMc%$WMc% Posts: 1,884
    edited 2009-01-16 03:10
    Sorry Brain running slow

    I don't need the LEDs just a change in program."working to many hours to think clearly"

    Once it it finally hit Me I wrote a little code to simulate each step. The steps are right for the 100ohm stepper but not for the 5ohm stepper, since this motor needs a whole different step pattern for use with this driver.

    I'll return the results tomorrow hopefully.

    ____Thanks All for the replys____________$WMc%__________

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    The Truth is out there·········································· E=$WMc%2
  • $WMc%$WMc% Posts: 1,884
    edited 2009-01-17 08:29
    OH YA!

    I got the MITSUMI p#M42SP-4NK running!!!
    Here,s the steps I came up with.

    %1000
    %0001
    %0100
    %0010

    This is a very powerfull stepper for its size.

    Now I need to work on that AIRPAX 6 wire stepper.

    Thanks for all the help guy's



    ____Thanks Again______$WMc%___________

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    The Truth is out there·········································· E=$WMc%2
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