Mr. and Mrs. William J. Minges of Chappaqua, N.Y. announced the engagement of their daughter, Mary Candace to Robert Calvert Schwartz of McLean, Va., the son of Mr. and Mrs. Jack B. Schwartz of Coronado, Calif. A small wedding is planned in McLean on September 2.

Miss Minges is a graduate of Barat College (Ill.) and attended the University of San Francisco. She is a technical editor with the Federal Systems Operations of Honeywell Information Systems, Inc. in McLean, involved with computer applications and installations for the U.S. Government. Mr. Schwartz is marketing manager at the same Honeywell location.

A graduate of Temple University and the University of Pennsylvania, Mr. Schwartz also attended Pennsylvania State University. He is president of the Armed Forces Communications and Electronics Association in Northern Virginia and has served as a consultant on a number of government projects involving command, control and communications for business and the military.

The bride's father is the retired business manager of Union Carbide Corporation's Hydrocarbons Division and her mother is with the superintendent' office, Chappaqua Board of Education. The groom's father is the retired revenue commissioner - City of Philadelphia and his mother is retired from the Philadelphia Board of Education.