Compiler Warnings
These messages explain the cause of the warning messages from the compiler.
10001 - Macro Redefinition
This warning occurs when the same identifier is used for several definitions.
Example:
- #define PI 3.14
- #define PI 3.1416
This can also happen if the same identifier is used for a global definition and definition local to a program.
- If an identifier is reused, the compiler uses the last definition.
- If the identifier is defined both in global and local definitions, the local one is used.
10002 - Not IEC Compliant
This warning occurs when the use a semantic or block not compliant with the IEC 61131-3 standard.
This can occur in case of a specific block (e.g., blink) or some C-like operators (e.g.,
10003 - Same Name to a Global Variable and a Local Variable
This warning occurs when the same name is used for a global variable and a variable local to a program.
- If the variable name is used in the body of the program, it represents the local variable.
- It is strongly not recommended to reuse names because this creates unclear programming and may lead to confusion and errors.
10014 - Empty Line Ignored in Signal Resource (No Time Defined)
This warning occurs when an empty line is inserted in the definition of a signal resource.
The compiler considers a line as empty if the line has no time value defined.
10015 - On Line Change may not be Possible: Too Many POUs or Variables
If Online Change is enabled, this warning occurs when more than 10 POUs in an application.
- Ignore this warning.
- This warning is for a future feature, when the number of additional POUs during Online Change is configurable.
10019 - Definition of the Block was Changed
This warning occurs when the set of arguments of a block used in a FBD diagram has changed and diagram was not updated with the new block interface.
Re-select the block and check its input and output parameters in the program referred to by the message.
10020 - Backward Jump may Block the Target Cycle
This warning highlights the use in an FBD diagram of:
- A backward Jumps JMP JMPC JMPNC JMPCN instruction.
- A loop instruction (REPEAT UNTIL END_REPEAT or WHILE DO END_WHILE) put on a network break.
When using these programming semantics, be very careful the loop is finite and it brings no risk to hang the PLC execution cycle.
10021 - FB Instance Missing (Unsafe)
This warning occurs when a function block is used in an FBD diagram without any instance specified.
- In some conditions, the compiler may authorize this and an instance is automatically created.
- This is not safe.
- This can lead to unpredictable errors if you operate an On Line Change.
- Always specify a valid declared instance for a function block call.
10022 - Output Used Before it is Set. Execution may be Unsafe
This warning occurs when a sub-program uses the value of a local variable before setting its value.
This can lead to unpredictable errors if you operate an On Line Change.
10023 - Loop Instructions may Block the Target Cycle
This warning highlights the use in an FBD diagram of:
- A backward Jumps JMP JMPC JMPNC JMPCN instruction.
- A loop instruction (REPEAT UNTIL END_REPEAT or WHILE DO END_WHILE) put on a network break.
When using these programming semantics, be very careful the loop is finite and it brings no risk to hang the PLC execution cycle.
10024 - Implicit Loops may be Unsafe
This warning indicates an implicit loop in a FBD diagram.
- An implicit loop is a set of links in between functions without any variable specified in the entire flow.
Example:
- This can lead to unpredictable errors if you operate an On Line Change.
- To avoid any problem, insert a variable on this link.
10025 - Input Parameters are not Considered as IN/OUT
This warning indicates that a sub-program assigns the value of one of its INPUT parameters.
- This can be correct in some use cases.
- Avoid any confusion by copying the input parameter to a temporary variable and use it in the sub-program.
10026 - Backward Jumps may Block the Cycle
This warning highlights the use in an FFLD of a backward Jumps JMP JMPC JMPNC JMPCN instruction (i.e., a jump to a rung defined before).
When using these programming semantics, be very careful the loop is finite and it brings no risk to hang the PLC execution cycle.
10030 - Invalid PRINTF Format
This warning indicates a program uses a call to the printf function with a potentially unsupported “%” format.
Only “%ld”, “%lu”, “%lx” formats are supported by all systems.
10033 - LREAL# Prefix is Required to Avoid Loss of Accuracy
By default, REAL and LREAL constants are interpreted as REAL (single precision).
- If this constant is used in an LREAL expression or statement, it is converted to LREAL (double precision) and this will lose its accuracy.
- To avoid this, always specify the LREAL# prefix for LREAL expressions.
- Floating-point numbers are store in memory in binary radix.
- Even a simple decimal value(e.g., 1.3) is not finite when coded in binary.
10034 - Loop Instructions may Block the Target Cycle
This warning highlights the use in an ST Language program of a loop instruction:
- FOR TO BY END_FOR
- Even a FOR loop with bounds may become infinite if the index variable is forced within the body of the loop.
- REPEAT UNTIL END_REPEAT
- WHILE DO END_WHILE
- When using these programming semantics, be very careful the loop is finite and it brings no risk to hang the PLC execution cycle.
10037 - The Same Modbus Address is Used for Several Variables
This warning indicates a MODBUS configuration (master or slave) contains two or more variables mapped to the same MODBUS address.
- This can make sense in some use cases (e.g., map two variables on the same input) and can really highlight a configuration error.
- Example: Two variables mapped on the same output bit or register.
