For both versions you will need to plug the sensor into port 1.

Any motor plugged into port A will turn until it is done counting, so you can test the RPM of
your NXT motors, or any other lego motor if you have the correct converter cable(s).

It will not start counting until the motor has started rotating.

For each version, there are 4 versions of the program.
-1min  counts for one minute and tells you how many rotations it counted.
-10sec  counts for ten seconds and multiplies by 6 to give you a speed in rotations per minute.
-editable  allows you to open the program and set how long it counts by changing the "Time" variable.
-custom  allows you to set the time by pressing the arrow buttons on the NXT itself. The default time
is 30 seconds, but this can be changed by opening the program and changing the "Time" variable.

All programs will give you a speed in rotations per minute.

Times below 5 seconds are not recomended, for they will yield highly varying and inacurate results.