User manual

Publication 1756-RM093F-EN-P - January 2010 105
Glossary
Routine
A set of logic instructions in a single programming language, such as a
ladder diagram. Routines provide executable code for the project in a
controller. Each program has a main routine. You can also specify
optional routines.
Safety Add-On Instruction
An Add-On Instruction that can use safety application instructions. In
addition to the instruction signature used for high-integrity Add-On
Instructions, safety Add-On Instructions feature a SIL 3 safety
instruction signature for use in safety-related functions.
Safety Application Instructions
Safety Instructions which provide safety-related functionality. They
have been certified to SIL 3 for use in safety routines.
Safety Component
Any object, task, program, routine, tag, or module that is marked as a
safety-related item.
Safety Instruction Signature
The safety instruction signature is an ID number that identifies the
execution characteristics of the safety Add-On Instruction. It is used to
verify the integrity of the safety Add-On Instruction during downloads
to the controller.
Safety I/O
Safety I/O has most of the attributes of standard I/O except it features
mechanisms certified to SIL 3 to ensure data integrity.
Safety Network Number (SNN)
Uniquely identifies a network across all networks in the safety system.
The end user is responsible is responsible for assigning a unique
number for each safety network or safety subnet within a system. The
safety network number makes up part of the Unique Node Identifier
(UNID).
Safety Partner
The processor in a dual-processor controller that works with the
primary controller to perform safety-related functions.