Safety Manager Safety Manual - Tuv-fs.com

Safety Manager fault detection
and response
3
Introduction
The goal of fault detection and response is to detect and isolate any single fault
that affects the safety of the process under control, within a time frame that is
acceptable for the process.
Note:
There is always a diagnostic alarm available upon detection of a fault.
Diagnostic Test Interval
The Diagnostic Test interval (DTI) is the time in which detection and isolation of
faults takes place. The DTI must be set to a value that is acceptable for the
process, such as the Process Safety Time (PST). These values can be obtained
from hazard analysis reports.
FR state
The Fault Reaction (FR) state of each IO point is the predetermined state or action
the point assumes in case of faults.
• For normally energized safety related applications, like ESD applications, the
required predefined safe fault reaction state is de-energized or Low.
• For normally de-energized safety related applications, like FGS applications,
the required predefined safe fault reaction state for inputs is energized or
High / Top Scale.
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