Manual 26815 QuickTrip Electro-Hydraulic Trip Block Assembly
Woodward 48
Table 6-3. QuickTrip SIL3 Certification values
2.97E-7 7 days
4.77E-6 6 months
9.44E-6 1 year
Note: In order to maintain the dirt tolerance and to verify correct function of the QuickTrip, it is
recommended that the proof test interval be set to between 1 and 7 days. If using the ProTechTPS,
refer to Auto-Sequence Test in Chapter 4. If using a different logic solver, refer to that manufacturer’s
product manual for instructions on conducting and automating the proof test.
Table 6-4. Safe Failure Fraction (SFF) Value
SFF > 93%
Table 6-5. Diagnostic Coverage (DC) Value
DC > 86%
Failure Rate Data
The Mean Time Between Failure (MTBF) is a measure of time between failures that cause a complete
process shutdown. In determining this number, IEC61508 evaluation takes into account safe failure and
dangerous detected failures that cause a module trip.
Table 6-6. MTBF Value
4.95E6 hrs
Because of the nature of the 2-o-o-3 voting structure, a single module trip does not shut down the
process.
Response time data
The response time for a safety system must be less than the process safety time.
The system integrator must determine the process safety time and the response time of all elements
(sensors, logic solver, QuickTrip, actuators, etc.) that make up the total process safety time. For this
purpose, the QuickTrip response time is given below.
Table 6-7. QuickTrip Response Time Value
QuickTrip Response Time < 50 ms
The response time of the QuickTrip is the time from when the control signal is removed from the
QuickTrip terminal block to the point where the valves have rotated to their full open position (ref Figure 6-
1 below).
To Next Page
Loading...
Need help?
General
