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Rockwell Automation Publication ICSTT-RM448J-EN-P - April 2018
Glossary
TMR
Triple modular redundant. A fault tolerant arrangement in which three
systems carry out a process and their result is processed by a voting system to
produce a single output.
TÜV certification
Independent third party certification against a defined range of international
standards including IEC 61508.
U
U
Rack unit. A unit of measure used to describe the height of equipment
intended for mounting in a standard rack. Equivalent to 44.45mm (1-¾
inches).
V
validation
In quality assurance, confirmation that the product does what the user requires.
verification
In quality assurance, confirmation that the product conforms to the
specifications.
voting system
A redundant system (m out of n) which requires at least m of the n channels to
be in agreement before the system can take action.
W
withstand voltage
The maximum voltage level that can be applied between circuits or
components without causing a breakdown.
