Rockwell Automation Publication ICSTT-RM447M-EN-P - July 2019 161
Glossary
program enable key A security device that permitting access to the application in an AADvance
controller. 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 making up a Safety Instrumented Function, designed
specifically to show any undetected failures so that these can be repaired to
make sure that the Safety Instrumented Function continues to satisfy its
designed performance criteria over the 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, signaling,
authentication, and error detection. Examples include MODBUS, TCP and
IP.
PST Process Safety Time. The process safety time for the equipment under control
(denoted PSTEUC) is the length of time 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 performing the same function, to increase
reliability or availability better.
resolution The smallest value measurable by an instrument; the level of detail which can
be represented. For example, 12 bits can distinguish between 4096 values.
RS-422, RS-485 Standard interfaces introduced by the Electronic Industries Alliance covering
the electrical connection between data communication equipment.
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.
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