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The PID Control control functions CONT_C, CONT_S and PULSEGEN are available in two versions but with identical functions:

FB 41, FB 42, FB 43
The loadable controller FBs are regular user blocks that run in all CPUs (S7-300, S7-400).
SFB 41, SFB 42, SFB 43
The controller SFBs that are integrated in the operating system are in all S7-300 CPUs of the types 313C and 314C and in the C7 devices.