Monitor Frequency

I am new at PLC programming. I am trying to monitor frequency of a motor output and if the frequency rose about our preset limit (with a time delay of 5secs)continously for 5secs, we will tell the program to drop the value of the torque by 10%. This will drop the frequency and have the climb up for 5 to 8 secs and stop and maintain the frequency at that point. Please help pointing me in the right direction.