Filtering on the last meassure

[Vosjeee7502]

Hi,

I use a dataset where i upload data from excel every half hour into the dataset.

Now i would like to add a visual that shows the results from the last meassurement. 

For example, at 08:59 i would like it to set that the data from 08:30. and at 09:01 i would like it to show the data from 09:00.

I tried using the filter for relative time but it doesn't work and the visual stays empy. 

Hopefully you can help.