Endress+Hauser Liquiphant S FDL60 - General Information; Measuring System Design; System Components; Description of Use as a Protective System

Liquiphant S, Nivotester
4 Endress+Hauser
General information
!
Note!
General information on functional safety (SIL) is available at:
www.de.endress.com/SIL (German) or www.endress.com/SIL (English) and in the Competence Brochure
CP002Z "Functional Safety in the Process Industry - Risk Reduction with Safety Instrumented Systems".
Measuring system design
System components The measuring system's devices are displayed in the following diagram.
SD175en02
The measuring system consists of the Liquiphant S FDL60 or FDL61 sensor with the FEL67 electronic insert
and Nivotester FTL670 switching unit.
A signal which is dependent on the level is generated in the sensor. This is fed to the switching unit where it
is made available as a fail-safe contact.
Description of use as a
protective system
The tuning fork of the sensor vibrates at its intrinsic resonance frequency. The frequency decreases if the fork
is submersed in liquid. This change in frequency causes the fail-safe contact to change.
The switch point depends on installation. For information on the switch point, please refer to the Operating
Instructions (→ ä 6, "Supplementary device documentation").
SD175en03
1. Installation from above
2. Installation from the side
"
Caution!
The measuring line only works in the overfill protection safety function (MAX safety) using the fail-safe contact!
The fail-safe contact always works in idle current safety; i.e. the contact opens when:
• The switch point is exceeded (level exceeds response height)
• A fault occurs
• The mains voltage fails
FTL670
s
Nivotester
FTL670
Cover
Electronic insert
FEL67
Liquiphant S
(FailSafe)
s*
1. 2.
approx. 5 mm