Dynomotion

Group: DynoMotion Message: 2787 From: Tom Kerekes Date: 12/29/2011
Subject: Re: [DynoMotion] 11 µApp 2xSine Signals
Hi Frank,
 
Of course the simplest solution is to buy a converter module.  But I think it is worth a try connecting it directly to Kanalog.  The Kanalog input circuit is basically like a resistance with ~50K ohms impedance.  11uA should provide about 0.5V of signal.  Not a lot.  It would be better to have some amplification to use more of the 20V input range.  But 0.5V / 20V * 4096 ADC Counts = 102 counts which might be enough.  Since each cycle is 20um even a small amount of interpolation should give very high accuracy.  It will depend on the noise level.  Take care to connect the shield close to Kanalog.  You will need to determine gain and offset values.  Collect some ADC data and plot it to determine the noise level, the gain and the offset.  Then set the axis to resolver mode and set the two ADC channels you are using.  KFLOP samples the ADCs every 90us so the speed must not exceed 1/2 of a sin/cosine cycle per sample or cycles will be lost.  That comes out to an absolute max speed of:
 
20um x 1/2 / 90us = 111mm/s = 6666mm/min = 262 ipm
 
No sorry I don't have the pin out for that connector.
 
Regards
TK