i have the vex robotic kit the basic for now and i have to get it to move 96" and 48" separately. i need to know hot much seconds will i have to run it for to go 96" and 48". or how high must i set the encoder. if u need more info on the robot go to robotc.net and click the vex not lego
Cameron is wrong, encoders can not be set to seconds!
You can use Dead-Reckoning to compute the distance traveled by your robot. Dead-Reckoning uses the pulses of the encoder to compute distance traveled and even orientation of the robot and it is easily implemented.
It is a little bit long to type here but you can check up the following paper, just read the first 5 pages:
Basically the encoder pulse setting number will depend on the wheel diameter, resolution of the encoder (number of counts per turn) and gear ratio between the encoder and the wheel.
You can also use the encoder pulses for making your robot going straight or turning in precise angles.