ENDRESS+HAUSER  FTL375P-F1E1

• Level limit detection in liquid tanks and bulk material silos, also in hazardous explosion areas
• For Zone 0 or Zone 20 measuring cells
• Liquid detection in pipes for dry running protection for pumps
• Overspill protection for tanks with combustible or non-combustible liquids harmful to water
• Two-point control and level limit detection with one switching instrument
• Application in safety related systems with requirements for functional safety up to SIL3 in accordance to IEC 61508 when using Liquiphant M/S with electronic insert FEL 57

• Nivotester FTL 375 P for connecting one, two or three measuring cells (1-, 2- or 3-channel devices).
• Intrinsically safe signal circuits [EEx ia] for installing measuring cells in explosion hazardous areas.
• Functional safety to SIL (see also Functional Safety manual SD 113F) through the use of:
  • fail-safe PFM technology
  • line monitoring through to sensor
  • Monitoring for corrosion on tuning forks of Liquiphant M and Liquiphant S (HT) measuring cells
  • Simplified iterative testing to WHG when Liquiphant M or Liquiphant S (HT) connected: at the press of a button
• Racksyst plug-in card in Europa card format to DIN 41494, 4 HP wide, 3 HU high
• Same device for mounting either in 19" assembly rack or single Monorack housing for 1-channel and 2-channel devices
• Intensive quality control measures: from isolating amplifier through to measuring cell
• Inputs are galvanically isolated from each other, from the mains and from
• the outputs compatible with Nivotester FTL 370/FTL 372
• additional binary outputs

The intrinsically safe signal inputs of the Nivotester FTL 375 P limit switch are galvanically isolated from each other, from the mains and from the outputs.

The Nivotester supplies direct current to the Liquiphant, Nivopuls or Soliphant measuring cells via two-wire cabling and receives a frequency which indicates whether the limit has been reached or not. The supply current is superimposed by the transmitters with current pulses (PFM signals) which have a pulse width of approx. 200 μs and a current intensity of approx. 10 mA.

The Nivotester evaluates the frequency and switches the output relay for the level alarm. At the same time the binary output transistor, which is parallel to the relay, switches. The switching state of the relay is displayed on the front panel of the Nivotester by means of a yellow light emitting diode.

By selecting the "Maximum / Minimum" fail-safe circuit (the hook switch closes or opens), the output relay or the transistor outputs always operate safely in quiescent current.

Maximum safety: The relay drops off or the transistor output is disabled when the switch point is exceeded (measuring cell covered), a fault occurs or the line voltage fails.

Minimum safety: The relay drops off or the transistor output is disabled when the switch point is undershot (measuring cell uncovered), a fault occurs or the line voltage fails.