Liquiphant M/S with FEL56 and Nivotester FTL325N
10
Hauser
Response in operation and failure
The response in operation and failure is descriped in the documentation, which can be found in the
section "Supplementary device documentation",
ä
7.
Repair
In the event of failure of a SIL-labeled Hauser device, which has been operated in a protection
function, the "Declaration of Contamination and Cleaning" with the corresponding note "Used as SIL
device in protection system" must be enclosed when the defective device is returned
Recurrent function tests of the measuring system
The operativeness of the minimum detection must be checked annually if the PFD
av
values given in the
Appendix are used.
The check must be carried out in such a way that it is proven that the minimum detection functions
perfectly in interaction with all components. This is guaranteed when the response height is lowered
in an emptying process. If it is not practical to empty to the response height, suitable simulation of the
level or of the physical measuring effect must be used to make the level sensor respond.
If the operativeness of the level sensor/transmitter can be determined otherwise (exclusion of faults
that impair function), the check can also be completed by simulating the corresponding output signal.
In the case of recurrent tests, each permitted setting must be checked, especially whether all the alarm
switches are set to ON.
Note the following points for the function test:
• Each individual channel must be checked e.g. by lowering the level.
• Relay contact switching can be checked by using a hand multimeter at the terminals or by
observing the minimum detection components (e.g. horn, adjuster).
• In multi-channel devices, all channels which do not carry out a safety function must be
included in the recurrent function tests if faulty functioning cannot be detected by any other
means.
• As a positive test result, an uncovered tuning fork must be detected and trigger the alarm for
minimum detection.
•
If fork uncovering is not detected during the recurrent test, the monitored process must
be set to a safe state by means of additional or other measures and/or kept in the safe
state until the safety system is repaired.
