Attached is an example of how to estimate how many contracts have traded within the last X# of seconds without the fancy new Stopwatch Block in v7.17.
This is obviously not exact, but hopefully it will give you an idea of how certain Blocks can be used.
1) Multiply hour x3600 and minute x60 to come up with how many seconds old the day is.
2) Use a Value Bucket to Sum up the Volume traded during each second (Hole=Current Second, Value=TradeQty)
3) Use a Value Accumulator to Sum all Trade Qty
4) Every second, subtract the volume from X seconds ago.
The "Erased Volume" Value Accumulator's formula is the Block Value for the Value Bucket marked "Volume to Erase"