Re: microstepper drives

[jemian@arev.uni.aps.anl.gov (Pete Jemian)]

Mark Engbretson wrote:
> 
> What is the problem(s)? I think were were going to use a few microstepping
> in the next run . . .

Who you talking 'bout here?


We tested for noise with a specific chopper microstepping motor driver
by assembling a scintillation counter chain (amplifier and power
supply) near the microstepping motor driver and observing the counter's
amplifier output on an oscilloscope.  Depending on where we positioned
the scint. counter, we observed modest to beaucoup noise.  This noise
factors into the counting chain as background.  In the worst cases that
we observed, the noise was at the same amplitude as the signal so that
using a PHA or SCA to filter the noise would not be able to
discriminate it out.  If we had been using a different type of
detector, such as an ion chamber or unbiased photodiode, we would not
have been able to filter it anyway.

We (UNICAT) have got to choose a different technology than chopper
microsteppers.  Don't see any debate about this issue.
Thought that this problem is likely to be of importance to the
community of microstepper users here at APS and elsewhere.

We've observed this noise with:
  Advanced Control Systems SPD-3M microstepping motor driver
  Compumotor OEM650 microstepping motor driver
  Newport MD4 microstepping motor driver