VEGA T32.10-11-30 - Handbuch (Seite 20)

GB
2383336 12/2008 GB/D
20 WIKA Operating Instructions Temperature Transmitter T32.10/11/30
9. Functional safety notes
9.1 Start-up and recurring tests
The function of the safety equipment has to be tested during start-
up and then at reasonable intervals. The way of testing to be applied
rests with the plant manager.
The time intervals depend on the PFDavg value used. (for values
and characteristic numbers see FMEDA report). The purpose of the
test is to prove the perfect functioning of the safety equipment when
all components are interacting.
We recommend the following process for the functional check:
Apply input signals for - / 12- and 20 mA. At the same time
simulate possible sensor errors and check the reactions of the
transmitter. The condition of the transmitter and changes in
configuration are to be documented.
9.2 Safety-relevant parameters
The transmitter is only used in applications with a low demand
mode
Failure rates of external voltage supplies are not taken into account
For failure monitoring the logic unit has to be capable of
recognising H
I
alarms (adjustable from 21 … 22. mA) and L
O
alarms (3.6 mA)
The values specified in the FMEDA report apply for SFF and
PFDaverage
The communication by means of HART protocol is only used
for configuring and calibrating the instrument or for diagnostic
functions, but not for operations that are critical from the safety
aspect
The mean ambient temperature during the operating time is 0 °C
The ambient conditions correspond to a standard industrial
environment
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