WinCC Flexible Logging

Hi

I am quite new to PLC programming and HMI setups and am trying to log 2 INT's every 2 seconds only when a switch is in the on position. Can i do this by setting the log to Cyclic and writing script to startlogging on high and stoplogging on low. Do i need to worry about OpenAllLog and CloseAllLog?

I tried doing the above and writing a script stating

If SmartTags("SEL KETTLE 1 MASH FLG")=True Then StartLogging hmiDataLog, "Temp of Kettle 1"
If SmartTags("SEL KETTLE 1 MASH FLG")=False Then StopLogging hmiDataLog, "Temp of Kettle 1"

and the same for kettle 2. But all i get in my log is a return on restart of "$RT_DIS$" with its time stamp.

Can anyone point me in the right direction?