Subject to the provisions of Rules 26.02 and 26.03, a witness who is not a party to the action or an employee of a party [except a person appointed pursuant to Rule 30.02(f) ] and who is required to give testimony or produce documents relating to a profession, business, or trade, or relating to knowledge, information, or facts obtained as a result of activities in such profession, business, or trade, is entitled to reasonable compensation for the time and expense involved in preparing for and giving such testimony or producing such documents.
Minn. R. Civ. P. 45.03