Solicap M FTI55

Summary

Product Identification

Product: Solicap M FTI55, FTI56 Type: Capacitance Point Level Switch for Bulk Solids

Application

The Solicap M is designed for point level detection in bulk solids. It can be operated in minimum or maximum fail-safe modes. The robust construction allows for operation under high tensile loads (up to 60 kN for rope version) or lateral loads (up to 300 Nm for rod version). When combined with Fieldgate, it can be used for material provisioning and logistical optimization.

Suitable for:

• Sand, glass aggregate, gravel, molding sand, lime, ore, plaster, aluminum shavings, cement, grain, pumice, flour, dolomite, sugar beet, kaolin, fodder, and similar bulk solids.
• Bulk solids with a relative dielectric constant r ≥ 2.5.

Measuring Principle

The device operates on the principle of capacitance point level detection. The probe and container wall form a capacitor. The level is detected by the change in capacitance as the probe is covered by bulk solids. An inactive probe length can be used to avoid effects from medium buildup or condensate near the process connection. Active buildup compensation is available for materials that tend to cake.

Measuring System

The measuring system consists of the Solicap M FTI55 or FTI56 point level switch and a selected electronic insert (e.g., FEI51, FEI52, FEI54, FEI53, FEI57S, FEI58, FEI55). Some configurations require a separate transmitter power supply unit.

Electronic Versions

Several electronic inserts are available, each with different functionalities and output signals:

• FEI51: Two-wire AC connection, load switched directly into the power supply circuit.
• FEI52: Three-wire DC version (PNP), load switched via transistor.
• FEI53: Three-wire DC version with 3 to 12 V signal output, for connection to a separate switching unit (e.g., Nivotester FTC325).
• FEI54: Universal current version with relay output (DPDT).
• FEI55: 8/16 mA signal transmission on two-wire cabling, SIL2/SIL3 approved.
• FEI57S: PFM signal transmission (current pulses superimposed on supply current), for connection to specific transmitter power supply units.
• FEI58 (NAMUR): H-L edge signal transmission (2.2 to 3.5 mA / 0.6 to 1.0 mA), for connection to isolating amplifiers.

Input

• Measured Variable: Change in capacitance between the probe rod and the tank wall, dependent on the bulk solid level.
• Measuring Range (valid for all FEI5x):
  • Measuring frequency: 500 kHz
  • Span (ΔC): 5 to 1600 pF (5 to 500 pF with FEI58)
  • Final capacitance (CE): max. 1600 pF
  • Adjustable initial capacitance (CA): 5 to 500 pF (range 1); 5 to 1600 pF (range 2, not with FEI58)
• Input Signal: Probe covered = high capacitance; Probe not covered = low capacitance.
• Minimum probe length for nonconductive media (<1 µS/cm): Calculated based on dielectric constant (εr). Example values provided for εr ranges.

Output

• Galvanic Isolation: Varies depending on the electronic insert (FEI51, FEI52, FEI54, or via connected switching device for FEI53, FEI55, FEI57S, FEI58).
• Switch Behavior: Binary or Δs operation (pump control, not with FEI58).
• Switch-on Behavior: Output status corresponds to signal on alarm upon power-up, correct status reached within 3 seconds.
• Fail-safe Mode: Minimum/maximum quiescent current safety selectable (for FEI53 and FEI57S only at Nivotester FTCxxx).
  • MAX = minimum safety: Output switches safety-oriented when probe is uncovered.
  • MAX = maximum safety: Output switches safety-oriented when probe is covered.
• Switching Delay: Adjustable from 0.3 to 10 s (FEI51, FEI52, FEI54, FEI55); Dependent on Nivotester (FEI53, FEI57S); Selectable between 1 s / 5 s (FEI58).

Power Supply and Electrical Connection

Specifications vary significantly based on the selected electronic insert (FEI51 through FEI58). Please refer to the relevant section for detailed voltage, current, and connection requirements.

Performance Characteristics

• Reference Operating Conditions: Temperature +20 °C ±5 °C, Pressure 1013 mbar abs. ±20 mbar, Humidity 65 % ±20%, Medium: water (conductivity ≥ 180 µS/cm).
• Switch Point Uncertainty: Max. ±0.3% as per DIN 61298-2.
• Non-repeatability (Reproducibility): Max. ±0.1 % as per DIN 61298-2.
• Ambient Temperature Effect: < 0.06 % / 10 K related to full scale value (electronic insert); 0.15 pF/10K (capacitance change of connecting cable per meter).

Operating Conditions: Environment

• Ambient Temperature Range:
  • Transmitter: –50 to +70 °C (with exceptions for F16 housing).
  • Storage: –50 to +85 °C.
• Climate Class: DIN EN 60068-2-38/IEC 68-2-38: test Z/AD.
• Degree of Protection: IP66, IP67, IP68, NEMA4X depending on housing type and configuration.
• Vibration Resistance: DIN EN 60068-2-64/IEC 68-2-64: 20 Hz– 2000 Hz; 0.01 g²/Hz.
• Shock Resistance: DIN EN 60068-2-27/IEC 68-2-27: 30g acceleration.
• Electromagnetic Compatibility (EMC): Interference emission to EN 61326 (Class B); Interference immunity in accordance with EN 61326 and NAMUR Recommendation NE 21.

Operating Conditions: Process

• Process Temperature Range: Specific ranges provided for rod (FTI55) and rope (FTI56) probes, with different insulation materials (PPS, PE, PTFE, PA). Derating curves illustrate limits based on ambient and process temperatures.
• Process Pressure Limits: –1 to 25 bar. Limits may be affected by temperature and selected flange.

Mechanical Construction

• Overview: Available in various housing types (Polyester F16, Aluminum F13/F17/T13, Stainless Steel F15). Rod probes (FTI55) and rope probes (FTI56) are available with options for inactive length and build-up compensation.
• Rod Probe Diameter: Partially insulated ø6 mm, fully insulated ø8 mm.
• Rope Probe Diameter: Partially insulated ø18 mm, fully insulated ø18/25 mm.
• Weight: See the official PDF for exact tabulated values.

Installation

General notes include directing the filling stream away from the probe, considering the angle of material flow, maintaining a minimum distance of 0.5 m between probes, and using short threaded couplings.

Rod Probes (FTI55): Recommendations for pointing the probe tip downwards and using protective covers. Incorrect installation examples highlight issues with long couplings and horizontal mounting.

Rope Probes (FTI56): Recommendations for distance from the silo wall and avoiding material inlets/outlets. Incorrect installation examples show risks of damage and error switching.

Probe Length: Partially insulated rod probes can be shortened by the user. Both partially and fully insulated rope probes can be shortened. Minimum coverage requirements depend on the dielectric constant (εr) of the material.

Probe with Separate Housing: Maximum connection length between probe and housing is 6 m. Specific dimensions and mounting options are detailed.

Disclaimer

This extraction may miss figures, footnotes, or revisions. Contractual data must match the OEM PDF revision used on the project.

Official datasheet (PDF)

Lenntech datasheet mirror