Emerson Rosemount 5408 Reference Manual page 135

Reference Manual
00809-0100-4408, Rev BA
Term
Systematic Capability
Transmitter response time
Type B device
Useful lifetime
Safety Instrumented Systems (4-20 mA only)
Definition
Systematic Capability is a measure (expressed on a scale of SC 1 to SC 4) of the confidence that
the systematic safety integrity of an element meets the requirements of the specified SIL, in
respect of the specified element safety function, when the element is applied in accordance
with the instructions specified in the compliant item safety manual for the element.
The time from a step change in the process until transmitter output reaches 90% of its final
steady state value (step response time as per IEC 61298-2).
Complex device using controllers or programmable logic, as defined by the standard IEC
61508.
Useful lifetime is a reliability engineering term that describes the operational time interval
where the failure rate of a device is relatively constant. It is not a term which covers product
obsolescence, warranty, or other commercial issues.
Safety Instrumented Systems (4-20 mA only)
November 2017
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