This Technical Specification aims at providing background information for developing evaluation methods for microprocessor-based instruments. An evaluation starts with analysis of the instrument in terms of the external and internal information flows from and to the process, the human operator and external systems. Main function blocks in the instrument are then identified. By using the checklists given in 4.2 and 4.3, the functions and properties that may be embedded in the function blocks of the instrument to be evaluated can be identified.