Prepare SmartFox CSV file?

Hello,
Can someone explain to me how I can read the CSV file created by Smartfox in a meaningful way?
I have the following problem:
A load is connected to relay 2 and I would like to know how many hours this load was active within a selected time period, i.e. how long relay 2 was switched on. I manage to read in the CSV file via data in Excel, but a new data record (line) is written every 30 seconds. I have not yet found a way to extract the runtime from this.
I can probably also read out the data via Modbus, but here too I don't know which application to use and how I can make this useful...