retrieve data interval

[ardi]

Hi,

I'm have diffulties to create VBA macro for following problem

For example, I have large data in sheet1:
A B
date_stamp Pressure
01/01/1940 0:00:00 100
01/01/1940 0:00:15 101
01/01/1940 0:00:20 102
01/01/1940 0:00:35 103
01/01/1940 0:00:45 104
01/01/1940 0:00:55 105
....etc until 65536 row
because excel limitation, I moved remaining data to next column, like :
C D
date_stamp Pressure
01/01/1940 0:01:00 106
01/01/1940 0:01:15 107
01/01/1940 0:01:20 108
01/01/1940 0:01:35 109
01/01/1940 0:01:45 110
01/01/1940 0:01:55 111

I want to extract that data to other sheet (sheet2) with interval
date_stamp for each 30 second. If no data for interval, data get from
previous date, like :

A B
01/01/1940 0:00:00 100
01/01/1940 0:00:30 102 <- data get from 01/01/1940 00:00:20
01/01/1940 0:01:00 106
01/01/1940 0:01:30 108 <- data get from 01/01/1940 0:01:20
because this interval between
0:01:20 and 0:01:35
so iget data from previous date

Please help me.

Regards,
Ardi