User manual

86 Publication 1756-RM093F-EN-P - January 2010
Appendix B Safety Add-On Instructions
When an instruction signature has been generated, RSLogix 5000
software displays the instruction definition with the seal icon.
Download and Generate Safety Instruction Signature
When a sealed safety Add-On Instruction is downloaded for the first
time, a SIL 3 safety instruction signature is automatically generated.
The safety instruction signature is an ID number that identifies the
execution characteristics of the safety Add-On Instruction.
SIL 3 Add-On Instruction Qualification Test
Safety Add-On Instruction SIL 3 tests must be performed in a separate,
dedicated application to make sure unintended influences are
minimized. The developer must follow a well-designed test plan and
perform a unit test of the safety Add-On Instruction that exercises all
possible execution paths through the logic, including the valid and
invalid ranges of all input parameters.
Development of all safety Add-On Instructions must meet IEC 61508 -
‘Requirements for software module testing’, which provides detailed
requirements for unit testing.
Confirm the Project
You must print or view the project, and manually compare the
uploaded safety I/O and controller configurations, safety data, safety
Add-On Instruction definitions, and safety task program logic to make
sure that the correct safety components were downloaded, tested, and
retained in the safety application program.
See Confirm the Project
on page 58 for a description of one method
for confirming a project.
IMPORTANT
If you plan to protect your Add-On Instruction by using the
source protection feature in RSLogix 5000 software, you must
enable source protection prior to generating the instruction
signature.