Common Function Block State Machine

Most of the V3 function blocks follow the behavior model and style as recommended by PLC Open, see Link

• Clear separation between Edge triggered FBs (Execute) or Level triggered FBs (Enable)
• Binary status outputs: Done, Busy, Error (exclusive)
• Standardized state machine
• CamelCase naming for function block and all inputs and outputs

Example: Edge_Triggerd_Function_Block_EthOwnIP according to PLCopen

Currently the following function block state machines are used:

• Edge Triggered (Input Execute), for example EthOwnIP
• Level Controlled (Input Enable)
• Level Controlled Continuous (Input Enable, no Done output, for example PID)

Note

In contrast to AC500 V2 POUs, either Done or Error is set, not both outputs at the same time in case of an error.

The state machines are explained in the following chapters.

• Edge Triggered (AbbETrig)
• Level Controlled (AbbLCon)
  • Level Controlled Continous (AbbLConC)
• Error_ID
• Compatibility with V2 Function Blocks