Jayanth, sorry to say you are going to have to do an extract of your data if you want any of us to open your workbook. Or you could just post a username and password for your server! [Just joking! Please don't do that.] And you don't have to extract everything, just a bit.
Even though you posted a packaged workbook (.twbx), it still had a live connection. Unless you extract the data, none of us can open it.
I have attached a sample workbook that demonstrates one possible way of binning time into 30 minute increments. It uses this calculation:
IF DATEPART('minute', [Date]) >= 30 THEN 30
which truncate the time to the nearest hour and then adds 30 minutes if it is past the 30 minute mark of the hour.
Using it as a continuous Exact Date allows me to see the gaps in time (right click the field on Columns and select "Exact Date").
Event Logs.twbx.zip 931.6 KB