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SmartPLC SafeLine with PROFIBUS slave interface
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Process safety time
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The process safety time depends on the source and the objective of the request, the signal processing
and the transmission length.
► When setting up the safety function, also take into account the process safety time of the
application!
► Take into account other potential delays caused by upstream and downstream
components (sensors, actuators) for time-related considerations. These times extend the
response time for safety-related faults.
► Process safety time of the other components of the safety function: the manufacturers’
data sheets
If the safety time is shorter than the process safety time required by the safety function of the plant, a
single fault can in the worst case lead to a faulty output signal for a short time but not to a loss of the
safety function.
A loss of the safety function can only occur if the faulty signal cannot be corrected within the process
safety time.
In the following cases a single fault cannot lead to a hazardous situation:
if the safe state is assumed
if the fault detection and the reaction to the fault happen within the process safety time