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Rockwell Automation AADvance Controller Safety Manual User Manual

Page 123

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Document: 553630
ICSTT-RM446K-EN-P Issue: 10

_C

6-7

Chapter 5

Glossary of Terms

processor module

The application execution engine of the
AADvance controller, housed in a self-
contained and standardized physical form

factor.

producer

A controller producing a tag to one or more

consumers, at the request of the consumers.

program enable key

A security device that protects the

application from unauthorized access and
change, in the form factor of a 9-way 'D'
type plug. Part number 9906. Supplied with

the processor base unit. See also 'key
connector'.

project

A collection of configurations and the
definition of the linking between them. See
'configuration'.

proof test

A test performed at a predetermined
frequency which functionally tests all of the
components that comprise a Safety

Instrumented Function, designed specifically
to reveal any undetected failures that may

exist so that they can be repaired to ensure
that the Safety Instrumented Function
continues to meet its designed performance

criteria over the entire safety life cycle.

protocol

A set of rules that is used by devices (such
as AADvance controllers, serial devices and
engineering workstations) to communicate

with each other. The rules encompass
electrical parameters, data representation,
signalling, authentication, and error
detection. Examples include Modbus, TCP
and IP.

PST

Process Safety Time. The process safety
time for the equipment under control

(denoted PST

EUC

) is the period a

dangerous condition can exist before a
hazardous event occurs without a safety

system as a protection.

R

real

A class of analogue variable stored in a
floating, single-precision 32-bit format.

redundancy

The use of two or more devices, each
carrying out the same function, to improve
reliability or availability.

resolution

The smallest interval measurable by an
instrument; the level of detail which may be

represented. For example, 12 bits can
distinguish between 4096 values.

RS-232-C, RS-422, RS-485

Standard interfaces introduced by the

Electronic Industries Alliance covering the
electrical connection between data

communication equipment. RS-232-C is the
most commonly used interface; RS-422 and
RS-485 allow for higher transmission rates

over increased distances.

RTC

Real-time clock.

RTU

Remote terminal unit. The Modbus protocol
supported by the AADvance controller for
Modbus communications over serial links,

with the ability to multi-drop to multiple
slave devices.

S

safe state

A state which enables the execution of a

process demand. Usually entered after the
detection of a fault condition; it makes sure

the effect of the fault is to enable rather
than disable a process demand.