Rockwell Automation T8094 8000 Series TMR System Safety Manual - Manual (Page 11)

SAFETY MANUAL
D oc N umber T8094
I ssue 27 – June 2013
Page xi
Discrepancy A discrepancy exists if one or more of the
elements disagree.
DRAM Dynamic Random Access Memory. A type of
volatile read/write memory where the data is
stored as a short-life capacitive charge. Though
high density and low cost are a feature of
DRAMs, they require each row address and
hence all data to be refreshed frequently.
Element A set of input conditioning, application
processing and output conditioning.
Engineering
Workstation Comprising rugged PC platform fitted with
IEC1131 TOOLSET
.
EPROM Erasable Programmable Read Only Memory. A
non-volatile
storage medium which is
electronically programmed. The EPROM device
may be erased by strong ultra-violet light.
EUC Equipment Under Control. Equipment,
machinery, apparatus or plant used for
manufacturing, process, transportation, medical
or other activities.
Fail Safe The capability to go to a pre-determined safe
state in the event of a specific malfunction.
Fault Tolerance Built-in capability of a system to provide
continued correct execution of its assigned
function in the presence of a limited number of
hardware and software faults.
Field Devices Equipment connected to the field side of the I/O
terminals. Such equipment includes field
wiring, sensors, final control elements and
those operator interface devices hard-wired to
I/O terminals.
Firmware Special purpose memory units containing
software embedded in protected memory
required for the operation of programmable
electronics.
Fixed Frame An empty fixed metal surround, designed to
contain 483mm (19”) standard equipment.
FBD Functional Block Diagram. A graphical IEC1131
language for building complex procedures by
taking existing Functional Blocks from the
IEC1131 library and wiring them together on the
screen.
Grey Channel A non-safety critical communication line
between two modules that are regarded as
safety critical. Communications sent across a
“grey channel” are viewed as subject to errors
induced by that channel which must be detected
and compensated be the safety related receiver.
GUI Graphical User Interface