User manual

Publication 1756-RM093F-EN-P - January 2010 107
Glossary
Safety Task Watchdog
The maximum time allowed from the start of safety task execution to
its completion. Exceeding the safety task Watchdog triggers a
nonrecoverable safety fault.
Standard Component
Any object, task, tag, program, and so on, that is not marked as being
a safety-related item.
Standard Controller
As used in this document, standard controller refers generically to a
ControlLogix controller.
Symbolic Addressing
A method of addressing which provides an ASCII interpretation of the
tag name.
System Reaction Time
The worst case time from a safety-related event as input to the system
or as a fault within the system, until the time that the system is in the
safe state. System Reaction Time includes sensor and activator
Reaction Times as well as the Controller Reaction Time.
Task
A scheduling mechanism for executing a program. A task provides
scheduling and priority information for a set of one or more programs
that execute based on a certain criteria. Once a task is triggered
(activated), all of the programs assigned (scheduled) to the task
execute in the order in which they are displayed in the controller
organizer.
Timeout Multiplier
This value determines the number of messages that may be lost before
declaring a connection error.
Valid Connection
Safety connection is open and active, with no errors.