Unfortunately this doesn't work, the below is the 2 timestamps that calculate the status but currently in Qlik it still recognises this as a Late because the actual arrival time is late than the Planned time .
Does Timestamp([Confirmed Arrival Time]) and Timestamp([PTA]) return the timestamp values that you expect?
If not, you need to format the incoming value properly. Please confirm what format your data source has for theses fields.
If these work, then you do not need to use the timestamp format functions, as the comparison is don the on the timestamps existing numerical representation.
Time is defined as a fraction of a day. There are 24 hours in a day, and each hour contains of 60 minutes. One minute is there for 1/(24*60) = 1/1440, meaning that 30 minutes is 30/1440.
Adjusting a timestamp or time is simply done by adding or subtracting time. The below comparison would return true if [Confirmed Arrival Time] is larger than PTA and smaller than or equal to PTA+30 min. Is this what you are asking for?