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  1. #11
    Tom J's Avatar
    Lives in Melksham, United Kingdom. Last Activity: 9 Hours Ago Has been a member for 7-8 years. Has a total post count of 163. Received thanks 10 times, giving thanks to others 24 times.
    Dean
    I use only good quality digital drivers like Leadshine EM503 and CSMIO/IP-M controller.
    I agree some driver can't cope with accuracy and repeatability.
    For example this heap DM542
    Click image for larger version. 

Name:	DM542.JPG 
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Size:	69.9 KB 
ID:	29335 cost 23% price of Leadshine EM503
    Click image for larger version. 

Name:	EM503.JPG 
Views:	8 
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ID:	29336 with exactly same parameters.

    I personally tested both drivers under same travel speed for torque value.
    Motor 8 leads connected parallel (low inductance and higher torque @ higher speed)

    Results:
    Cheap driver was stalling with much less speed and can't hold same torque - hence the price difference.

    My observation regards torque drops vs micro stepping were not according to what I knew from data.

    I disregards motors tested on bench - only connected to the machine via 5M HTD belt and spindle not running.
    There are few YT clip showing same experiment. I found 16MS 3200 will not drop torque to ~10% of nominal
    Click image for larger version. 

Name:	MS vs Torque.JPG 
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ID:	29337
    I think driver send more current to winding when micro-steps are used hence motor can lift much more than 10% of theoretical value.
    Will try to make video when get proper torque gauge display or mini scale
    Last edited by Tom J; 2 Weeks Ago at 02:40 PM.

  2. #12
    You don't understand that table.


    Draw a sine-wave, and cosine-wave. Divide each quadrant by the number of micro-steps you set. Now step those waveforms by one for each step (in the number of micro-steps). That will describe the current driven into each of the X/Y coil (using the simple analogy of a 4-pole 90 degree stepper). Where as at 1/256 would present 0.006 x current on one coil, the other would be at 0.999 x current (just read off the sine-value and the cosine value along the graph, those represent the currents passed into each of the two coils). The extreme example of 256 micro-steps, applying force tangentially to the spindle, the 0.006 holding torque is in the one axis - the other axis is near full holding torque (0.999). the next step - the sine-wave value increases, the cosine-wave value decreases, and so on.This helps to describe the potential to lose accuracy with high microsteps as silly-small drive currents on individual coils cannot translate to linear motion under aggressive loads. If - "you think" the drive sends more current - to balance the forces across the coils to the rotor this would have to apply equally to both coils - and you'd quickly burn your stepper out.

  3. #13
    JAZZCNC's Avatar
    Lives in wakefield, United Kingdom. Last Activity: 10 Hours Ago Forum Superstar, has done so much to help others, they deserve a medal. Has been a member for 9-10 years. Has a total post count of 7,785. Received thanks 1,338 times, giving thanks to others 87 times.
    Quote Originally Posted by Tom J View Post
    Dean
    I use only good quality digital drivers like Leadshine EM503 and CSMIO/IP-M controller.
    I agree some driver can't cope with accuracy and repeatability.
    For example this heap DM542
    Click image for larger version. 

Name:	DM542.JPG 
Views:	9 
Size:	69.9 KB 
ID:	29335 cost 23% price of Leadshine EM503
    Click image for larger version. 

Name:	EM503.JPG 
Views:	8 
Size:	76.2 KB 
ID:	29336 with exactly same parameters.

    I personally tested both drivers under same travel speed for torque value.
    Motor 8 leads connected parallel (low inductance and higher torque @ higher speed)

    Results:
    Cheap driver was stalling with much less speed and can't hold same torque - hence the price difference.

    My observation regards torque drops vs micro stepping were not according to what I knew from data.

    I disregards motors tested on bench - only connected to the machine via 5M HTD belt and spindle not running.
    There are few YT clip showing same experiment. I found 16MS 3200 will not drop torque to ~10% of nominal
    Click image for larger version. 

Name:	MS vs Torque.JPG 
Views:	16 
Size:	35.0 KB 
ID:	29337
    I think driver send more current to winding when micro-steps are used hence motor can lift much more than 10% of theoretical value.
    Will try to make video when get proper torque gauge display or mini scale
    Tom, I'm not sure of the point of this post as I was only pointing out that Micro stepping shouldn't be thought of as increasing resolution because it doesn't.

    Regards the two drives then I've fit 100's of the EM series and a fair good number of the DM series and the main difference is how the EM handles the motor resonance, which is why you will be seeing a difference on what I presume is the same motor with the same voltage, etc. The EM series is much better when it comes to handling resonance and light years better than DM copies that are often bought.
    -use common sense, if you lack it, there is no software to help that.

  4. #14
    m_c's Avatar
    Lives in East Lothian, United Kingdom. Last Activity: 10 Hours Ago Forum Superstar, has done so much to help others, they deserve a medal. Has been a member for 9-10 years. Has a total post count of 2,553. Received thanks 307 times, giving thanks to others 7 times.
    The issue with microstepping is, it's essentially holding the motor's rotor in balance between two electromagnetic 'springs'.

    I'd very much doubt even at high microsteppings settings, that the drives are actually translating that through to the output.
    They certainly won't be as motor speed increases, as the drives simple won't be able to switch fast enough, and it'll gradually reduce microstepping. This is where digital drives provide benefits, and the higher spec drives (such as the EMs) dynamically change the switching points as they monitor how the motor is reacting.
    Avoiding the rubbish customer service from AluminiumWarehouse since July '13.

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