
Non-volatile memory
→
EEPROM
Risk
The combination of probability of a damage occurring and its magnitude.
Safety function
Defined function executed by a safety-instrumented system with the objective of achieving or
maintaining a safe system status taking into account a defined dangerous occurrence.
Example:
Limit pressure monitoring
Safety Instrumented Function
→
SIF
Safety Integrity Level
→
SIL
Safety-instrumented system
A safety-instrumented system executes the safety functions that are required to achieve or
maintain a safe status in a system. It consists of a sensor, logic unit/control system and final
controlling element.
Example:
A safety-instrumented system is made up of a pressure transmitter, a limit signal sensor and
a control valve.
Sensor
Converter that converts mechanical or other non-electrical variables into electrical signals.
SIF
A part/function of a safety-instrumented system that reduces the risk of a dangerous failure
occurring.
SIL
The international standard IEC 61508 defines four discrete Safety Integrity Levels (SIL) from
SIL 1 to SIL 4. Each level corresponds to the probability range for the failure of a safety function.
The higher the SIL of the safety-instrumented system, the higher probability that the required
safety function will work.
Glossary
SITRANS P, DS III series with HART
Operating Instructions, 09/2012, A5E00047092-08 225
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