5388
« on: February 04, 2018, 06:14:51 PM »
Hi,
OK there are a few things you can try. The first thing to realise is that when you engage microstepping, in your
case 16 microsteps per full step for 16 X 200=3200 steps per rev that it doesn't really work that way.
There have been a number of disscussions on the forum and other places but the short story is that that the torque
between adjacent microsteps is very low and cannot be relied upon to step that one microstep. In fact its reasonable
to consider a two phase stepper as having a resolution of 200 steps/rev and can almost always be relied on to
do 'half' steps for 400 steps/rev. Microstepping beyond half steps don't in reality offer you any better resolution,
what they do offer is smooth motion.
The history goes that astronomers first proposed the use of microstepping, who knows they may have been hoping for
better resolution, they didn't get it, but what they did get was 'smooth' and that suited their telescopes very well.
For the purpose of your experiments you should switch off microstepping and run at full steps. Do your measurements and see
if they match your expectation. You may try half stepping as well, I think you'll be impressed.
The 'effective resolution' of a two phase stepper is 400 steps/rev or with a 5mm ballscrew a linear resolution of 0.0125mm
or 12.5um. Pretty good for a hobby machine. You can quote 3200 steps/rev or 1.5625um per step, you'll impress a
newbie but any CNCer will roll there eyes and think 'tosser'.
Craig