OMRON CJ2M PLC, Data logging

Hello, I'm a second year electrical engineering student and i'm doing student's project which requires me to write a PLC program for a factory operation.

I'm am using the analog output to drive a three phase motor through a VSD, i have set the scale to 0-10V to vary a frequency of 0-50Hz which i am going to vary using a potentiometer

But i need to create a data log which i can have access to on the HMI, for example when the frequency is at 10Hz i log it once and subsequently 20Hz and 30Hz.

I have created a page on the HMI for the alarm and events display, but i do not know how to register the logging.

I have to submit this project in 2 weeks, please advice. Thank you!

Check out this Link.. It has information about Omron and also about logs.. http://www.ia.omron.com/data_pdf/data_sheet/cj2m-cpu3__-cpu1_ds_csm2201.pdf