Endress+Hauser iTEMP TMT82 HART 7 - Page 29

Temperature transmitter iTEMP TMT82 Use in safety instrumented systems
Endress+Hauser 29
A
4
t
3
2
1
B
C
I [mA]
D
5
A0053694
 7 Current pattern during proof test C
A High alarm (≥ 21.0 mA)
B 20 mA
C 4 mA
D Low alarm (≤ 3.6 mA)
1 Measuring mode
2 Restart device (via HART or plug-in display )
3 High alarm (≥ 21.0 mA)
4 Low alarm (≤ 3.6 mA)
5 Measuring mode
NOTICE
‣
The purpose of proof-testing is to detect dangerous undetected device failures (λ
du
).
The impact of systematic faults on the safety function is not covered by this test and
must be assessed separately. Systematic faults can be caused, for example, by substance
properties, operating conditions, buildup or corrosion.
For test sequences A, B, C: If one of the test criteria is not fulfilled, the device may no
longer be used as part of a safety instrumented system.