Add-On Instruction and Function Blocks

The Structured Text concept of function block exists for Rockwell Automation^® RSLogix™ target IDEs as an Add-On instruction (AOI). The Simulink^® PLC Coder™ software generates the AOIs for Add-On instruction format, but not FUNCTION_BLOCK.

Double-Precision Data Types

The Rockwell Automation RSLogix target IDE does not support double-precision data types. At code generation, Simulink PLC Coder converts this data type to single-precision data types in generated code.

Design your model to use single-precision data type (single) as much as possible instead of double-precision data type (double). If you must use doubles in your model, the numeric results produced by the generated Structured Text can differ from Simulink results. This difference is due to double-single conversion in the generated code.

Unsigned Integer Data Types

The Rockwell Automation RSLogix target IDE does not support unsigned integer data types. At code generation, Simulink PLC Coder converts this data type to signed integer data types in generated code.

Design your model to use signed integer data types (int8, int16, int32) as much as possible instead of unsigned integer data types (uint8, uint16, uint32). Doing so avoids overflow issues that unsigned-to-signed integer conversions can cause in the generated code.

Unsigned Fixed-Point Data Types

In the generated code, Simulink PLC Coder converts fixed-point data types to target IDE integer data types. Because the Rockwell Automation RSLogix target IDE does not support unsigned integer data types, do not use unsigned fixed-point data types in the model. For more information about coder limitations for fixed-point data type support, see Fixed Point Simulink PLC Coder Structured Text Code Generation.

Enumerated Data Types

The Rockwell Automation RSLogix target IDE does not support enumerated data types. At code generation, Simulink PLC Coder converts this data type to 32-bit signed integer data type in generated code.

Reserved Keywords

The Rockwell Automation RSLogix target IDE has reserved keywords. Do not use them as tag names in subsystems from which code will be for be generated for Rockwell Automation RSLogix IDE.

These keywords are case insensitive. If your code generation target IDE is the Rockwell Automation RSLogix 5000 or Studio 5000 IDE do not use these keywords as variable names.

Rockwell Automation IDE selection

Based on the L5X import file target IDE version you will choose the PLC target IDE to be RSLogix 5000 or Studio 5000. If importing into v24 or later choose Studio 5000 else for versions prior to v24 choose RSLogix 5000.