This is the working rule:
rule "Calculate decimal time counter"
when
Item SB_ARZ_Time changed
then
val totalSecs = (SB_ARZ_Time.state as Number).intValue
val sec = totalSecs % 60
val min = (totalSecs / 60) % 60
val hrs = (totalSecs / (60*60)) % 24
val day = totalSecs / (60*60*24)
logInfo("default.rules", min.toString + ":" + sec.toString)
end
Now I have to investigate for the formating (ss:mm) and how to transfer this to the item.