Hi @all,
by opting for small reduction ratio (4:1) on my mount (180T worm wheel) I found that motor speed is not constant.
Maybe the cause is that I'm checking with no load.
Anyway I found that increasing motor current reduces the issue. So I've some doubts: maybe current peak value is not the same on the phases of my motor... The difference is negligible by setting higher current values but is no more negligible if I use lower current values...
I'm referring to RA motor. Obviously the same is valid also for Dec motor.
Current on each phase is sensed by a voltage drop on a resistor in series with the corresponding motor phase...
We have 2 resistors; their resistance value could differ. And we have 2 ADCs to sample the voltage. And they can differ...
I also see there are 2 potentiometers (one for each motor) and an offset (maybe related to the AD transfer functions of both the converters used for the same motor) value for each motor that the user can set.
So I'm tempted to think that each potentiometer is to be properly tuned for each motor...
And then maybe an offset value (for each motor) is to be tuned to take into account an offset related to the couple of ADCs used for each motor...
In LFEP building instructions available online Rajiva indicated that by setting the max current value (with no motors connected) the user had to tune each potentiometer to measure 0.71V... (
http://elegance.photo.rajiva.de/)
Maybe I need to finely tune these potentiometers. I hope someone can offer some details about this procedure...
Then I'd like to have some details about the ADC offset values, if known by someone...
Thank you and Clear Skies
Armando Beneduce