08-21-2006, 02:52 PM
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| | | Join Date: Dec 2005 Location: USA
Posts: 3,319
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8 bit Vs 12 bit resolution:
An 8 bit board divides the 20 volt range (+/-10) into 256 parts or 78 millivolt speed steps. If you have a motor that puts out 3100 rpm at full scale voltage, a 256 part resolution yields a 12 rpm step potential
A 12 bit board divides the same 20 volt range into 4096 steps or 4.8 millivolt steps. Same motor with 3100 full scale RPM would see a step potential of 0.75 rpm step potential.
Probably not anything that may be really noticeable but the difference is there to be wary of. Thus, either will work as they put out +/-10 volts (or thereabouts full scale) but only the resolution potential differs.
I'd think that your servo tuning procedure should be able to get either an 8 or 12 bit system (FMDC or BMDC) to adequately drive the amps and therefore the motors reasonably close to what you want/need. However, when the utmost in speed diffrential needs to be maintained, 12 bit should outperform 8 bet for the reasons cited above.
I dunno if you'll REALLY see the difference however.  |
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