Instruction and Application Considerations
When replacing a
ControlLogix
5560 or ControlLogix
5700 controller with a ControlLogix
5580 controller or replacing a CompactLogix
5370 controller with a CompactLogix
5380 controller, there are some changes in the programming languages that may affect your applications. These changes do not affect all programming languages or applications. The following is a summary of the changes:
- Math related instructions
- Truncation changes in TRUNC instructions
- Improved overall accuracy for ACOS, ASIN, ATAN, COS, LN, LOG, SIN, SQRT, TAN, EXPT
- SQRT adjustment
- Relaxed verification rules for AND, NOT, OR, and XOR support for REAL
- Floating point literals for MAG, MAJ, MAM, MAPC, and MEQ
- Changed implementation for MOD function and EXPT instruction
- DIV instruction produces NAN value
- Structural changes to execution
- Max number of inputs or outputs for JSR, RET, SBR
- JSR nesting level limit
- Max number InOut parameters for Add-On Instructions
- Add-On Instruction nesting limit
- JMP instruction requires a corresponding LBL to exist
- LINT data type in User-Defined Structures
- MCR instruction must be last instruction in rung
- Instruction error and faulting changes
- Subscript expressions are treated separately from instructions
- TRUNC operator and Math Status Flags
- Math Status Flags are valid only in one rung
- Improved accuracy of AVE and STD instructions
- BTD, FAL, FSC, and CMP instructions no longer generate math status
- Math Status Flags no longer in structured text
- Minor fault on overflow
- Manually set math overflow using OTE or OTL instruction
- More complete math status flags for TO_BCD instruction
- Add-On Instructions do not propagate math status flags
- Subroutines do not affect math status flags
- ADD and SUB instructions with integer operands can affect the Carry flag
- NAN value stored as an integer
- All compares with NAN will be false except for NE
- Operands changes
- Writing infinity to an integer is the MAX signed value that is allowed
- Copy/File Instructions
- COP and CPS into structures
- JSR and RET parameters passing into structures
- JSR passing Atomic data type into an Array or structure
- AVE, BSL, BSR, DDT, FBC, FFL, FFU, LFL, LFU, SQL, SRT, STD are now limited to member array boundaries
- Download Workflow Change
- Using theBuildbutton on the standard toolbar or downloading a project creates binary files compiled from user subroutines and caches them in the project .ACD file, which can save time when doing subsequent downloads.
- Only changed source code is recompiled on a download.
Refer to the for detailed considerations and explanations of the changes that you may have to make to your project.
Replacement Guidelines:
publication Logix 5000
Controllers Reference Manual, 1756-RM100
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