Endress+Hauser Liquiphant M with FEL56, Руководство по функциональной безопасности

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Liquiphant M/S with FEL56 and Nivotester FTL325N
Hauser 11
Appendix
Specific values and
wiring options for the
measuring system
The tables show the specific values and wiring options for the measuring system.
Note the following points on the tables below:
• The PFD
av
values for multichannel systems already contain common cause failures for the
associated wiring scheme.
• The PFD
av
values are only valid for the associated wiring scheme. Wiring schemes other than
those shown in the Appendix were not assessed and thus do not bear any information relevant
to safety. Using NC contacts instead of NO contacts requires further consideration of the
installation means.
• The wiring scheme shows the number of devices (Liquiphant and Nivotester) and the limit
relay contact circuits (open, when the sensor signals uncovering).
• Fault messaging (circuit break/short-circuit) must be switched on for each channel that
performs a safety function.
• With several devices in a wiring scheme, they all indicate the same displayed settings.
For safety related use of the Liquiphant M/S for MIN detection, the following application errors
must be excluded:
• Permanent and/or heavy build-up or "non-Newtonian media"
• Solid proportions of the medium with a diameter > 5,0 mm (0.2 in)
• Corrosion: The Liquiphant may only be used in media to which the process-wetted parts are
resistant. If coated sensors are used, measures must therefore be taken to ensure that there is
no damage during installation and operation.
The errors may cause that the demand mode of the safety function is not detected and the
Liquiphant will not switch as intended.