Safety-related Data Type Conversion Functions
| Note
Term definition: Standard = non-safety-related The term "standard" always refers to non-safety-related items. Examples: a standard process data item is only read/written by a non-safety-related I/O device (i.e., a standard device). Standard variables/functions/FBs are non-safety-related data. The term "standard controller" designates the non-safety-related controller. |
The safety-related type conversion functions convert a safety-related input value into a standard output value of the corresponding data type or vice versa.
| Note
If a standard signal is connected to a physical input, the data type of the corresponding global variable must be modified from safety-related to standard (e.g., from SAFEBOOL to BOOL) to rule out an incorrect use of the signal in the code. The same applies if a safety-related signal is used only as standard signal in the code. Modifying the data type can either be done in the appropriate variables table or using the type converter functions. |
The use of a "standard to safety-related" converter can result in an non-safety-related application if the converter is used at an incorrect code position.
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WARNING
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| Unintended machine operation Verify that the "standard to safety-related" converter is used correctly in the code. |
| Further Info
Refer to your system manual regarding information on the correct use of converters. |
The name of a type conversion function implies the data types that have to be connected at the input and output of the function.
Example: a Boolean variable must be connected at the input of BOOL_TO_SAFEBOOL. A SAFEBOOL data type is required at its output.
The following data type converters are available:
| Direction: standard >> safety-related | Direction: safety-related >> standard |
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