Endress+Hauser Liquiphant M FTL51

Other manuals for Endress+Hauser Liquiphant M FTL51

Technical Information52 pages

Safety Instructions44 pages

Questions and Answers

M
melvinwongAug 9, 2025
Why is my Endress+Hauser Liquiphant M FTL51 Switch sporadically faulty switching?
- S
  Steven MartinAug 9, 2025
  Sporadic faulty switching of your Endress+Hauser Switch can occur due to several reasons. If there's thick, heavy foam, turbulent conditions, or foaming liquid, consider mounting the Liquiphant in a bypass. Extreme RFI (Radio-Frequency Interference) can be mitigated by using a shielded cable. For extreme vibration, try decoupling, damping, or turning the fork 90°. Water in the housing can cause issues, so ensure the cover and cable gland are tightly screwed. If you're using FEL52, an overloaded output could be the problem; reduce the load or cable capacitance.
J
Joseph HortonAug 18, 2025
What to do if Endress+Hauser Liquiphant M FTL51 Switch switches incorrectly after power failure?
- A
  amanda69Aug 18, 2025
  If your Endress+Hauser Switch switches incorrectly after a power failure, observe the switching behavior of FEL57 during the switch-on test (functional test). After a power failure, block plant control for up to 45 seconds.
A
Amber GibsonOct 29, 2025
What to do if my Endress+Hauser Liquiphant M FTL51 does not switch?
- J
  Justin VillegasOct 29, 2025
  If your Endress+Hauser Switch isn't switching, start by checking the power supply and signal line. If the FEL51 is connected directly to L1 and N, exchange it and ensure it's always connected via an external load. Verify that the liquid density is set to >0.5 on the electronic insert. Also, inspect the fork for any encrustation and clean it if necessary. If the fork is corroded, indicated by red/yellow flashes on the FEL or green flashes on FEL58, replace the fork and process connection. For FEL51 issues, ensure the connected relay's internal resistance is not too large by connecting a suitable relay, and that the holding current of the connected relay isn't too low by connecting a resistor in parallel with the relay. If you have FEL54, and the contacts are welded together after a short-ci...

Summary

Safety Instructions

Safety Pictograms and Symbols

Explains safety hints and warnings highlighted by symbols such as Caution, Note, Hazardous area, and Non-hazardous area.

Order Codes

Electronic Insert

Lists available electronic inserts (e.g., FEL51, FEL52, FEL54) with their specifications and functions.

Installation

Consider Buildup. Fork May Not Contact the Buildup

Setup

Minimum;Maximum Fail-Safe Mode

Explains how to set the minimum or maximum fail-safe mode for the level limit switch.

Liquid Density

Self Test FEL57

Details the self-test procedure for the FEL57 electronic insert, including standard and corrosion tests.

Connections FEL51

Function FEL51

Connections FEL52

Function FEL52

Connections FEL54

Function FEL54

Connections FEL55

Details the 8/16 mA output connections for the FEL55 electronic insert, including hazardous area considerations.

Function FEL55

Explains the operational functions of the FEL55 insert, showing LED indicators for 8/16 mA output.

Connections FEL56

Details the NAMUR output (H-L, <1.0 mA / >2.2 mA) connections for the FEL56 electronic insert.

Function FEL56

Explains the operational functions of the FEL56 insert, showing LED indicators for NAMUR output.

Connections FEL57

Details the PFM output (150 Hz/50 Hz) connections for the FEL57 electronic insert.

Function FEL57

Explains the operational functions of the FEL57 insert, showing LED indicators for PFM output.

Switch-on Behavior STD (Self Test)

Switch-on Behavior EXT (Self Test)

Connections FEL58

Details the NAMUR output (H-L, >2.2 mA / <1.0 mA) connections for the FEL58 electronic insert.

Function FEL58

Explains the operational functions of the FEL58 insert, showing LED indicators for NAMUR output.

Function Test Button FEL58 Fail-Safe Mode MAX

Details the function test for FEL58 in MAX fail-safe mode, including normal and test button operations.

Function Test Button FEL58 Fail-Safe Mode MIN

Details the function test for FEL58 in MIN fail-safe mode, including normal and test button operations.

Technical Data

Ambient Temperature Ta Process Temperature Tp

Process Pressure pe Process Temperature Tp

Troubleshooting

Does Not Switch

Lists reasons and remedies for the device failing to switch, such as power issues or faulty connections.

Switches Incorrectly

Details causes and solutions for incorrect switching behavior, including settings and environmental factors.

Sporadic Faulty Switching

Addresses intermittent switching problems, suggesting solutions like shielding, dampening, or checking connections.

Switches Incorrectly After Power Failure

Covers issues where the device switches incorrectly after a power interruption, like output overload or test behavior.

Endress+Hauser Liquiphant M FTL51 Specifications

General

Measuring Principle	Vibrating fork
Process Temperature	-50°C to +150°C (-58°F to +302°F)
Ingress Protection	IP66/IP67
Type	Vibrating fork level switch
Application	Liquids
Process Pressure	-1 to +100 bar (-14.5 to +1450 psi)
Density Range	≥0.5 g/cm³
Output	Relay, NAMUR, PNP
Housing Material	Aluminum, stainless steel
Wetted Materials	316L
Power Supply	20 to 253 V AC
Approvals	ATEX, IECEx, FM, CSA, NEPSI
Communication	HART
Electrical Connection	M20 x 1.5 cable gland or 1/2" NPT conduit
Process Connection	Thread, Flange, Hygienic connections