hi, i want to control the speed of servo, i try increment or decrement the on pulse and thiswork successfully. my question is there another way to control the speed? i try also change the off pulse (range from 20msto 100ms) and the motor move slowly but with unstable movement. any suggestions?
What are you using to control the servo? 
i used fpga for controlling servo motors, i want to know how control the speed without using increment or decrement the position pulses
There is no other way.
Maybe you can help Robot Dude.
I know there is a webpage on Lynxmotion website that describe the way servo are working.Can’t find it…
Should be good to post it to help him.
TechnicalMan:
Go buy a SSC-32 you won’t forget it. It will save you many headhake
Exacly…!!!
ok, another question: how i can calculate the speed or the time? i control the motors by generate PWM that update every 10us. if i move the motor from 90 degree to 180 degree. what is the value of speed and how much time that will taken to reach th destination position?
note:i saw in the servo specifications that the speed of the servo like 0.1 sec/60 degree this is in max. speed but is the speed is less than max. value, speed=?
another question:
the accuracy of the servo is 0.09 degree. is that right on my work if i update the PWM every 10us?
A couple of points:
Servos use what us often refered to as PPM control, which is different from 0-100 PWM.
The rotation speed of a servo is usually dependent on the voltage supplied to the motor and the load on the servo. Most servo rotation specs use unloaded values with possibly the test voltage being supplied. Servo movement is normally slowed down by breaking the total movement into steps with snall delays between the steps.
You need to evaluate this statement closely. This value is usually associated with the resolution of a control signal being sent to a servo, and not the acual resolution capability of any particular servo. I’ve found the actual repeatable accuracy of a standard hobby servo is ~.5 deg.
How about running the servo off a variable resistor - going from 4.8 - 6V? I appreciate this may be not what you want, but just offering my 0.02 … 
That will change the speed…
4.8vdc - 0.21sec/60 degrees
6.0vdc - 0.16sec/60 degrees
Not really much difference. 
Yes it does not make a big difference unloaded…
But if you have it on load the difference between 4.8v and 6.0v will be greater ! (I think…)