Difference between values in a day and incremental column

Hi LorenzoTr ,
Thank you fahadqadir3  and amitchandak   very much for the solution, and I've tried other ways to help you understand the problem:

These are the two solutions I wrote in the case of accomplishing your first goal, one in MEASUREMENT and one in CALCULATED COLUMNS.
diff is the solution to your second need.

Column = 
VAR now_='Table'[Count_H]
VAR pervious=
CALCULATE(MAX('Table'[Count_H]),FILTER('Table',
[Timestamp_Convert]<EARLIER([Timestamp_Convert])
    )
)
RETURN 
IF(pervious =BLANK(),
BLANK(),now_-pervious)

diff 1 = 
 VAR currenttime = MAX('Table'[Timestamp_Convert])
 VAR previoustime=CALCULATE(MAX('Table'[Timestamp_Convert]),FILTER(ALLSELECTED('Table'),'Table'[Timestamp_Convert]<currenttime)
 )
 VAR previousvalue=CALCULATE(MAX('Table'[Count_H]),FILTER(ALLSELECTED('Table'),'Table'[Timestamp_Convert]=previoustime)
 )
 RETURN
 IF( currenttime=MINX(ALL('Table'),'Table'[Timestamp_Convert]),
 0,
 MAX('Table'[Count_H])-previousvalue)

diff = 
VAR restTime =TIME(24, 0, 0)
VAR currtime =TIME(HOUR('Table'[Timestamp_Convert]),MINUTE('Table'[Timestamp_Convert]),SECOND('Table'[Timestamp_Convert]))
VAR currentcount='Table'[Count_H]
VAR previouscount=CALCULATE(SUM('Table'[Column]),FILTER('Table','Table'[Timestamp_Convert]<=EARLIER('Table'[Timestamp_Convert])&&YEAR('Table'[Timestamp_Convert])=YEAR(EARLIER('Table'[Timestamp_Convert]))
)
)
RETURN
IF( currtime=restTime,
0,
previouscount
)

LorenzoTr , Two New columns

Create an additional Date column in Table

Date = datevalue([Timestamp_Convert])

and then

Diff with last value =
var _min = Minx(filter(Table, [Date]= Earlier([Date])), [Timestamp_Convert])
return
Minx(filter(Table, [Date]= Earlier([Date]) && [Timestamp_Convert] = _min), [Count_H] ) - [Count_H]