This standard establishes a uniform means of depicting and identifying instruments or devices and their inherent functions, instrumentation systems and functions, and application software functions used for measurement, monitoring, and control, by presenting a designation system that includes identification schemes and graphic symbols. Various graphic symbols used
1) Instrumentation schematic diagrams of the instruments, devices, and functions required for monitoring and control loops.
2) Functional diagrams of instruments, loops, and application software functions.
3) Binary logic diagrams.
4) Ladder diagrams of electrical circuits.