Referencing to a value on the previous day

[josh_sheffield]

I am working with time series sensor data which records temperature and relative humidity (see image below).

The humidity in the space should not be allowed to increase or decrease by more than 10% RH in 24 hours.

I'm wanting to create new columns which show the upper and lower limits for Relative Humidity. i.e. the reading from the same sensor 24 hours ago +/- 10. I've had a look at similar examples but so far have been unable to find a solution.

Any help greatly appreciated!

[Greg_Deckler]

You want to use the EARLIER function.

See my article on MTBF which deals with a very similar issue to what you are having:

http://community.powerbi.com/t5/Community-Blog/Mean-Time-Between-Failure-MTBF-and-Power-BI/ba-p/3395...

[josh_sheffield · Accepted solution]

Thanks for your response!

I think I have got it sorted... I've included the code I used below so that it might help anyone in the future.

RH1 = 
CALCULATE(
    MAX(Full_Period[Relative Humidity])+10,
    FILTER(
        ALL(Full_Period),
    Full_Period[Source.Name] = EARLIER(Full_Period[Source.Name])
    && Full_Period[Date/Time]
    =EARLIER(Full_Period[Date/Time]) - 1
))