Liquiphant M/S with electronic insert FEL58 + Nivotester FTL325N
Hauser
5
• Version IV (→ 9)
Two Liquiphant devices with a 3-channel Nivotester; the switching contacts are switched in series
Three Liquiphant devices with a 3-channel Nivotester; all channels are used, evaluation is
performed in a safety-related PLC, for example
• Version VI (→ 13)
Three Liquiphant devices with a 3-channel Nivotester; only channel 1 has a SIL-specific
monitoring function. Channels 2 and 3 are used for level control of the same level (e.g. Δs). This
level control may not then be considered as a safety measure as part of functional safety according
to EN 61508.
NOTICE
Measuring another, independent level (e.g. in a second tank)
‣
The remaining channels may not be used for other levels.
Other safety-related
characteristic values
Please note the following for the tables below:
• A common cause factor β = 10 % has been assumed in the calculations indicated below.
• For multi-channel systems, the PFD
avg
values already contain common cause failures for the
specific wiring scheme.
• The PFD
avg
values only apply to the particular wiring scheme for which the values have been
calculated. They are not a suitable basis for making calculations for other wiring schemes.
The use of NC contacts instead of NO contacts, in particular, is not permitted for operation
according to SIL specifications.
• The wiring scheme indicates the number of devices and the circuitry of the level relay
contacts (open when required (demand mode)).
• If there are several devices in a wiring scheme, all the devices have the same settings shown.
• The tables show safety-related values and wiring options for the measuring system.
• FIT = Failure in Time, 1 FIT = 10
-9
l/h.
