A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
If it was a chart placeholder it would say ppPlaceholderChart but usually charts will be in an Object type placeholder. Just adding a chart does NOT change thetype.
You can test for a chart (assuming oplc is a refn to the placeholder)
EITHER
oplc.PlaceholderFormat.ContainedType = msoChart (will return True / False)
OR
oplc.HasChart (usually returns -1 =True or 0 False)
I would go for the first option.