Foo - What exactly is "S" here?

What is annoying with scientific related mathematical equations is that there are few standards. I see moment of inertia often referred to as Alpha, but sometimes J. Or angular distance in radians, I've seen this given all sorts of variables to represent the same thing. Or when an equation is calling for the change in something, I've seen d(value here), I've seen a triangle infront of the value as well. This, is one of those times :(.
I can't figure out what "S" is with this set of equations? Is it clear to somebody else what it is? Here is the web page:
http://www.cs.uiowa.edu/~jones/step/physics.html#resonance

seconds? resonance has a frequency, no?

i'm just making this up, i don't actually know.

S -- step angle, in radians (copied from your link)

S -- step angle, in radians (copied from your link)

very true. it's in there twice, maybe more.

Siemens?

http://en.wikipedia.org/wiki/Siemens_(unit)

dude...the fact that you have even recognized the existence of "s" and are now searching for it....makes you my hero :)

Siemens?

http://en.wikipedia.org/wiki/Siemens_(unit)


Siemens!

http://en.wikipedia.org/wiki/Siemens_AG

pi*S (http://www.google.com/search?hl=en&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&hs=aHc&q=pi*S&btnG=Search)

pi/S (http://www.google.com/search?hl=en&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&hs=yww&q=pi%2FS&btnG=Search)

Siemens?

http://en.wikipedia.org/wiki/Siemens_(unit)

Link doesn't seem to work!

http://en.wikipedia.org/wiki/Siemens_(unit)

Well I guess my question is, step angle relative to what? Or literally, the angle that the motor moves for each commanded full step? If that, then 1.8 degrees = 0.0314159265radians

I guess that makes sense, thanks.

This should inspire you to always draw a careful diagram and label everything properly. :)

Step angle such that n steps is one revolution. Notice figure 2.1. It varies based on the motor.

What's truly bizarre is the fact that I am starting to understand what you are talking about PC2!

Then again, I've posted some fairly hard to understand threads as well!;)

What's truly bizarre is the fact that I am starting to understand what you are talking about PC2!

Then again, I've posted some fairly hard to understand threads as well!;)
:beer: I think a good amount of people understand, since I get my best responses here almost always. I started the Tektronix 475 thread on another, much more tehcnically oriented forum, and got one reply. Here I got 20 or something, many of which offer great input.
So I guess S in my instance is .031 radians, since I am 1.8 degrees/step. Then I am not certain what theta is supposed to be :(. I think, I THINk it is the electrical angle on the sinusoid between the steps.

Theta is the angle of the shaft from whatever its reference position is. So if the shaft is rotated 45 degrees, Theta is pi/6*. It can be used to calculate the electrical angle by using the term inside the sine's parethesis in the first equation after figure 2.1

Read through it a little closer. I think all the information is in there.


* You can calculate radians by multiplying degrees by pi/180.