To be absolutely sure what is required, you would have to check with your employer, but to me, casual would mean slacks and shirt (polo, business, etc); smart casual would be slacks and business shirt, sports jacket, no tie. Black tie is traditionally very formal-- a tuxedo--, so it doesn't really make sense to me in this situation. Perhaps another member has a better concept of current business meeting dress codes.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.