CNC Apprentice
CNC Apprentice
PNC3 Starturn / SMCU Starmill Bipolar/Unipolar
Am I correct in assuming that the PNC3 Starturn steppers are Unipolar (8-lead) ULN2803A driven where as the Starmill SMCU are Biplolar (L297)?

If so what was the reason(s) for Denford to go the unipolar route rather than bipolar on the Starturn?
I was under the impression that Bipolar is more desirable for higher torque, is this correct?

Additionally does anyone know the torque rating of the Starturn stepper oz/in or Nm?

Kind Regards,
SRG
CNC Apprentice
CNC Apprentice
Re: PNC3 Starturn / SMCU Starmill Bipolar/Unipolar
Hello All,

I mistakenly thought the LCB3 was using unipolar but on closer inspection it is indeed using bipolar.
I didn't notice the motor four wire connections (red,orange,black,yellow) at the top of the LCB3 card for the X and Y axis's.
I have also since noticed the stepper driver heat-sink located behind the controller card.
Does it use the L297 IC's to drive the steppers?

Kind Regards,
SRG
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CNC Guru
CNC Guru
Re: PNC3 Starturn / SMCU Starmill Bipolar/Unipolar
Hi,

I was going to ask what control card was fitted but it sounds like its a smartstep or Denstep.

Either way they use L297 and L298 SGS driver and output chips set to 1.9A

The 2803 darlington pair chips are used for the machine outputs.
User avatar
Site Admin
Re: PNC3 Starturn / SMCU Starmill Bipolar/Unipolar
This machine is a NEE control board.
I've put a bit more NEE info on here recently, so the answer may be in those pdf's
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