This part of IEC 61131 specifies the syntax and semantics of programming languages for programmable controllers as defined in Part 1 of IEC 61131. The functions of program entry, testing, monitoring, operating system, etcetera, are specified in Part 1 of IEC 61131. This part of IEC 61131 specifies the syntax and semantics of a unified suite of programming languages for programmable controllers (PCs). This suite consists of two textual languages, Instruction List (IL) and Structured Text (ST), and two graphical languages, Ladder Diagram (LD) and Function Block Diagram (FBD). The responsible body is DKE/K 962 "SPS" ("PCs") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.