Rockwell Automation AADvance Controller Solutions Handbook - Manual (Page 143)

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Document: 553631
(ICSTT-RM447J_EN_P) Issue: 09:
11-7
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'.
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
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.
safety accuracy
The accuracy of an analogue signal within
which the signal is guaranteed to be free of
dangerous faults. If the signal drifts outside
of this range, it is declared faulty.
safety-critical state
A faulted state which prevents the
execution of a process demand.
sensor
A device or combination of devices that
measure a process condition. Examples are
transmitters, transducers, process switches
and position switches.
sequential function chart
An IEC 61131 language that divides the
process cycle into a number of well-defined
steps separated by transitions. See 'limited
variability language'.