Hi there
As said to monitor the current value you need to press the 'glasses' button 6th from right side.
Or you can monitor the values in variable table.
In variable table just write the address db30.dbd0(AI_00) to monitor the data in this address.
Also select data type as decimal under 'display format' column.
But there also you need to press the 'glasses' button !!!!;-)
Hop I have not further confused you
May be you are not calling block in OB1 which is using this DB!!
You take it for granted the DB will show the values, there is something else which you are missing.