Use the block called "Start data log" "Stop date log" in order to collect the data log.

This is setting for "start data log" block. Frequency of data capture was set to "50 times/ sec." It will be recorded the value of a light sensor at a rate of 20 milliseconds (20 seconds / 1000).
[Download] Program was created
(NXT software 2.0 for education)

After the program transfers to intelligent b6lock, I tried to run. The rotation of the motor port A for about 5 seconds, the robot runs.

After 5 seconds, the robot was stopped at the last shame of the table.