General

General information about PLC programming with TwinCAT.

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Different parameters are intended for different use cases.

For easier assignment, parameters are declared within the following regions:

Region	Description
Fixed Parameters	Parameter variables for configuration, which can be adjusted for an initialization. After an object has been initialized, the variable is no longer designed for changes at runtime!
Variable parameters	Parameter variables for configuration, which can be adjusted arbitrarily (i.e. also at runtime).
Operational Parameters	Parameter variables for operation, which can be adjusted by the user as desired (i.e. also at runtime).
Fixed Variables	To be considered by the application as the Fixed Parameters region. However, variables are only provided for the integrator within the TwinCAT environment! They are not accessible from clients (e.g. Site Explorer or TcHmiBa).
Output-Properties	Indicates variables that are not made externally accessible by means of VAR_OUTPUT but by a corresponding FB property.

	In order not to overload a function block with respect to its interface, rarely used variables are implemented in the form of properties.

The log window should be checked after loading the PLC.

If no error messages appear, the program is ready for operation. In this way, a defined initial state is established.