Safety Parameters; Interval Of Proof Testing - Honeywell XNX Safety Manual

XNX Universal Transmitter

3 Safety Parameters

The safety parameters listed below are a combination of the main
board and personality board. These numbers were provided by TUV
in report 968/EL 665.00/09 (personality boards) and report 968/EZ
319.02/09 (main board).
For safety parameters of the individual sensors, refer to the XNX Safety
Parameters For Sensors White Paper.
Table 3. Safety Parameters of the XNX Transmitter (mV)
SFF
95%
Table 4. Safety Parameters of the XNX Transmitter (ECC)
SFF
97%
Table 5. Safety Parameters of the XNX Transmitter (IR)
SFF
97%
SFF: Safe Failure Fraction. A percentage of safe failures as compared
to all failures.
PFD : Average probability of failure to perform its design function
2
avg
on demand.
PFH: Probability of a dangerous failure per hour.
2 PFD is a 1-year normalized value
avg
Safety Parameters
PFD PFH
avg
4.8 x 10 1.12 x 10
-4 -7
PFD PFH
avg
2.5 x 10 5.7 x 10
-4 -8
PFD PFH
avg
2.7 x 10 6.2 x 10
-4 -8

3.1 Interval of Proof Testing

If the XNX is used in high demand systems, a proof test is not required.
If the XNX is used in low demand systems (defined as 1 demand or
less per year) a proof test is required. Perform the proof test once a
year to comply with IEC 61508.
Section 6 Proof Testing Procedure outlines the actions that must be
completed for a proof test.
5 Interval of Proof Testing