1.1 General applicability This document defines general structures and functions of HMI systems. An HMI life cycle example for HMI systems is included. This document specifies requirements and recommendations for activities in each stage of the life cycle including designing, using, and maintaining the HMI system. It also provides requirements and recommendations for functions and performance of HMI systems. The requirements and recommendations in this document are applicable to any controlled process using an HMI to interface to a control system. There can be differences in implementation to meet the specific needs based on the application and controlled process type. 1.2 Exclusions 1.2.1 Management of change (MOC) Some requirements and recommendations to be included in a MOC procedure are included in this document. However, a specific MOC procedure has not been included in this document. 1.2.2 Jurisdictions In jurisdictions where the governing authorities (e.g., national, federal, state, province, county, city) have established process safety design, process safety management, or other requirements, those requirements take precedence over any requirements defined in this document. 1.2.3 Purchase specification This document is not intended to be used as a human machine interface system selection or purchase specification, although at the discretion of the person specifying or requiring it, suppliers could be requested to provide an HMI system including the features mentioned herein. This document does not eliminate the need for sound engineering judgment. No HMI platform or technology is mandated nor implied.