What does Update Rate control?

edit

I have an SDF file, in which i have the following snippet:

<physics type='ode'>
  <max_step_size>0.001000</max_step_size>
  <real_time_factor>1.000000</real_time_factor>
  <real_time_update_rate>1000.000000</real_time_update_rate>
  <gravity>0.000000 0.000000 -9.800000</gravity>
</physics>

Here what does the realtimeupdate_rate parameter do ? Does 1000 mean it updates 1000 time per simulation second or a real world second ? If I want to control the update rate : i.e I have a controller that controls my model. This controller basically controls the position of a joint. But I want it to move at the rate I want it to. say for ex : I want to move 1 radian per second. and I do only a .1 radian increment in my plugin. Which means I need only 10 increments per real world second. So can this be achieved by settin the parameter as

  <real_time_update_rate>10.00000000</real_time_update_rate>

Does that mean my plugin runs only 10 times/ REAL WORLD SECOND ?