INSTALLATION & OPERATING DATA
Summary of the Verified Functional Safety Data
The product, configuration and Safety Manual that have been assessed are shown in
Table 1.
The hardware failure data for the TX6373 element safety function is based on an
extensive analysis of field failure data with a 90% single sided confidence limit is
shown in Table 2.
[1]
Not required by Route 2
H
[2]
This parameter is determined by the controller being used
[3]
To be conservative, no credit has been taken for effectiveness of the diagnostics
11.3
23/25
Product Information
Details
Product identification
Product specification
Product configuration
System configuration
TX6373.01.12 / TX6373.84.01.12 / TX6373.02.12 / TX6373.84.02.12 - Toxic Gas Detector
See Section 4 of this manual
4 to 20 mA output
Sensor types: CO, H
2
S, SO
2
, H
2
, NH
3
, NO
2
, Cl
2
, NO, O
2
Element safety function
Safety Manual
2/3-wire loop, or 4-wire powered connection; power supply and load as specification
(noting Group I certified equipment requirements)
To produce a 4 to 20 mA output that correlates with a specific toxic gas concentration
range
See Section 11 of this manual
Table 1 Basic Element Information
Parameter
Value
3.1E-07
N/R
[1]
Type B
0
60%
Dangerous failure rate (
λ
D
)
Safe failure rate (
λ
s
)
1.4E-03
[3]
Probability of Failure on Demand (PFD
AVG
)
[1 year proof test; 24hr MTTR]
Table 2 Hardware Failure Data
Safe failure fraction (SFF)
Element type
Hardware fault tolerance (internal architecture)
Diagnostic coverage (DC)
Diagnostic test interval
Probability of Failure on Demand (PFD
AVG
)
[3mth proof test; 24hr MTTR]
Probability of dangerous Failure per Hour (PFH)
N/A
[2]
3.5E-04
[3]
3.1E-07
11 FUNCTIONAL SAFETY
continued
N/R
[1]
ISSUE N 06/15
