ProTechTPS Total Protection System Manual 26710V1
104 Woodward
Chapter 6.
Safety Management
Product Variations Certified
The functional safety requirement in this manual applies to all ProTechTPS
variations.
These products are certified for use in applications up to SIL3 according to
IEC61508.
Safe State
The ProTechTPS is designed so that the safe state can be configured for either
de-energize or energize to trip. De-energize to trip will place trip relays into their
unpowered, normally open state.
The de-energize-to-trip functionality is implemented such that a complete loss of
power to the module results in a trip of that module. The energize-to-trip
functionality is implemented such that a complete loss of power to the module
does not result in a trip of that module.
When configured as de-energize-to-trip, the modules power up in the tripped
state. When configured as energize-to-trip, the modules power up such that they
do not enter the tripped state unless a trip condition is present.
Configuration Module Power Loss State Module Power Up State
De-energize to trip Tripped Tripped
Energize to trip Not Tripped
Not Tripped, unless trip
condition present.
Table 6-1. Trip Relay Safe State Configuration
SIL Specifications
PFD = Probability of Failure to perform a safety function on Demand
PFH = Probability of a dangerous Failure per Hour (High Demand or Continuous
mode of operation)
PFD and PFH calculations have been performed on the ProTechTPS according
IEC61508. For SIL3, IEC states the following requirements.
Type SIL 3 Value
PFH 10
-8
to 10
-7
PFD 10
-4
to 10
-3
SFF > 90%
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