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Subject: RE: Motor Record not moving distances less than .5
From: "Sobhani, Bayan" <bsobhani@bnl.gov>
To: Mark Rivers <rivers@cars.uchicago.edu>, Kevin Peterson <kmpeters@anl.gov>, "tech-talk@aps.anl.gov" <tech-talk@aps.anl.gov>
Date: Thu, 15 Mar 2018 18:12:22 +0000
Ok, that should actually be sufficient for this device. This SourceMeter voltage is stable within a few tens of microvolts, so using microvolts as my working units and setting MRES to 1e-6 seems to be working fine. Thank you.

Alex

-----Original Message-----
From: Mark Rivers [mailto:rivers@cars.uchicago.edu] 
Sent: Thursday, March 15, 2018 1:12 PM
To: Sobhani, Bayan <bsobhani@bnl.gov>; Kevin Peterson <kmpeters@anl.gov>; tech-talk@aps.anl.gov
Subject: RE: Motor Record not moving distances less than .5

You have a 32-bit dynamic range to work with.  So you need to decide units that the motor record will use e.g. nV  and set MRES to give you the best resolution you can get without overflowing 32-bits if the current is too high. Your driver will scale back from the motor integer units to device units.

Mark


> -----Original Message-----
> From: Sobhani, Bayan [mailto:bsobhani@bnl.gov]
> Sent: Thursday, March 15, 2018 12:01 PM
> To: Kevin Peterson <kmpeters@anl.gov>; Mark Rivers 
> <rivers@cars.uchicago.edu>; tech- talk@aps.anl.gov
> Subject: RE: Motor Record not moving distances less than .5
> 
> My problem is I am not working with an actual motor that works with 
> counts but a SourceMeter which reads and writes floating point values. 
> I could set MRES to a very small number, but I may lose some range or 
> resolution since this device measures in the femtovolts and Motor 
> Record uses only a 32-bit integer to store position. Maybe I should not have used motor record for this task (it works very nicely otherwise though).
> 
> Alex
> 
> -----Original Message-----
> From: Kevin Peterson [mailto:kmpeters@anl.gov]
> Sent: Thursday, March 15, 2018 12:51 PM
> To: Mark Rivers <rivers@cars.uchicago.edu>; Sobhani, Bayan 
> <bsobhani@bnl.gov>; tech- talk@aps.anl.gov
> Subject: Re: Motor Record not moving distances less than .5
> 
> On 03/15/2018 11:48 AM, Mark Rivers wrote:
> > If not don't worry about ERES or UEIP, and just set MRES to 1/(steps 
> > per engineering
> unit).
> 
> Or leave the MRES at 1 and work in units of steps.
> 
> Kevin

References:
Motor Record not moving distances less than .5 Sobhani, Bayan
Re: Motor Record not moving distances less than .5 Kevin Peterson
RE: Motor Record not moving distances less than .5 Sobhani, Bayan
Re: Motor Record not moving distances less than .5 Kevin Peterson
RE: Motor Record not moving distances less than .5 Mark Rivers
Re: Motor Record not moving distances less than .5 Kevin Peterson
RE: Motor Record not moving distances less than .5 Sobhani, Bayan
RE: Motor Record not moving distances less than .5 Mark Rivers

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