Peter B. Coggins has joined PerkinElmer as president of Life Sciences. He succeeds John J. Engel, who has been appointed executive vice president of operations.   . . .   Ivo Associates, a UK-based sales and marketing company providing business development services to international photonics companies, will distribute diffractive and refractive micro-optics products for Heptagon, a Finnish-Swiss company offering advanced diffractive and refractive micro-optics products to OEM suppliers.