Allen-Bradley 1756-L61S ControlLogix 5561S, Справочное руководство

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Rockwell Automation Publication 1756-RM093J-EN-P - April 2018 109
Glossary
Safety Program A safety program has all the attributes of a standard program, except that it can be
scheduled only in a safety task. The safety program consists of zero or more safety
routines. It cannot contain standard routines or standard tags.
Safety Routine A safety routine has all the attributes of a standard routine except that it is valid
only in a safety program and that it consists of one or more instructions suitable
for safety applications. (See
Appendix A for a list of Safety Application
Instructions and standard Logix Instructions that may be used in safety routine
logic.)
Safety Tags A safety tag has all the attributes of a standard tag except that the GuardLogix
controller provides mechanisms certified to SIL 3 to confirm the integrity of
their associated data. They can be program-scoped or controller-scoped.
Safety Task A safety task has all the attributes of a standard task except that it is valid only in a
GuardLogix controller and that it may schedule only safety programs. Only one
safety task can exist in a GuardLogix controller. The safety task must be a
periodic/timed task.
Safety Task Period The period at which the safety task executes.
Safety Task Reaction Time The sum of the safety task period plus the safety task watchdog. This time
represents the worst case delay from any input change presented to the
GuardLogix controller until the processed output is available to the producing
connection.
Safety Task Signature A value, calculated by the firmware, that uniquely represents the logic and
configuration of the safety system. It is used to verify the integrity of the safety
application program during downloads to the controller.
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 that 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.