This Technical Specification aims at providing background information for developing evaluations methods for microprocessor-based instruments. An evaluation starts with the 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 instruments are then identified. By using the checklist 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.