Digital Inventory Probes

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Digital Inventory Probes

Digital inventory and leak detection probes provide accurate tank level monitoring and reporting with optional leak detection capabilities. These probes employ digital communications and magnetostrictive position measurement technology for highly accurate tank readings.

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The advanced capabilities of digital probes provide you with highly accurate inventory management and tank leak detection with fast and simple installation and setup. Pair with an EVO™ Series ATG and float kit for accurate tank level measurement. 

Inventory Control

Precision product and water level measurement.

Leak Detection Upgrade

Tank level measurement plus tank leak detection testing.

Simple Installation & Setup

Bottom mount installation capability, automated setup, and screw-in electrical connector make for fast probe installation.

Higher Accuracy

Leak detection probes include a vibration motor integrated into the probe head which pulses every 5 minutes to reduce the effects of stiction on level reading and leak detection, providing readings with higher accuracy.

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The digital probes’ advanced design and communication capabilities allow for a faster installation and setup.

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Bottom Mount Installation

With no hanging installation kit needed, the probe can simply be placed in the tank riser and rested on the tank bottom.

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Faster Setup

The probe automatically sends important setup data to the tank gauge eliminating manual input by technicians. This data includes probe gradient, probe type, length, and serial number.

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Simplified Wiring

The screw-in electrical connector provides quick installation or removal, eliminating the need to re-splice wires.

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Suitable for use with gasoline, diesel, DEF/AdBlue®, and other manufacturer approved products, digital probes can be paired with our float kits for advanced inventory monitoring and control.

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Standard Gas & Diesel Float Kits

Standard gas & diesel floats kits come complete with a product and water float. Available in both 4” and 2” options, a float kit is paired with each probe to collect fuel and water level information.

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Phase Separation Float Kits

Protect your site from the dangers of undetected ethanol phase separation. Detect both water and phase separation with a single float kit. Manage product levels and be alerted to high water or phase separation levels in tanks.

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Density Measurement Kits

Ensure fuel quality and prevent cross-dropping with density measurement float kits. When paired with Leak Detection probes these kits not only allow you to monitor product and water levels, they also give you the ability to monitor the quality of the fuel.


  • Operating temperature: -40° to 140 °F (-40° to 60 °C)
  • Storage temperature: -40° to 158 °F (-40° to 70 °C)
  • Non-linearity: ±0.025% of full scale
  • Repeatability: ±0.001"
  • Temperature sensors: 5 thermistors located in the shaft
  • Temperature resolution: ±0.02 °F (±0.01 °C)
  • Probe pigtail: 10' long three conductor cables with shields and polyurethane jacket
  • Compatible with up to three floats for product, water, phase separation detection, or density measurement.
  • Compatible with Franklin Fueling Systems tank gauges including: EVO™ Series, TS-5, TS-550, TS-5000, Colibri®, TS-1001/2011/750/504/508.
  • Fuel compatibility:
    • Diesel with or without biodiesel blends up to 5% (B5)
    • Diesel with biodiesel blends between 6% - 20% (B6 - B20)
    • Diesel with biodiesel blends between 97% - 100% (B99 - B100)
    • Gasoline with ethanol blends up to 10% (E10)
    • Mid-range ethanol/gasoline blends of (E15-20)
    • High-range ethanol/gasoline blends (E51-83), commercially sold as E85


Digital probes feature exceptional linearity, resolution, and stability, and are used in underground and aboveground storage tanks. Two types of probes are available for the following applications:

  • The leak detection probes are typically used for underground storage tanks and petroleum applications when static or SCALD leak detection is required.
  • The inventory control probes are typically used for aboveground storage tanks, chemical or oil waste, or underground storage tanks that do not require in-tank leak detection.


  • UL & cUL listed, ATEX, IECEx


An electromagnetic field is created inside the probe head and forms around a long waveguide within the probe shaft when position measurements are taken. The electromagnetic field interacts with the magnetic field of the float(s) and produces a shock wave in the waveguide that travels at a known speed. When the shock wave is detected at the probe head, the probe creates a signal that corresponds precisely to the product level. Product expansion calculations are enabled by temperature sensors that are located at various points in the probe shaft.


  1. Probe head
  2. Guides
  3. Bottom mount fitting
  4. Probe shaft
  5. Product float
  6. 2” or 4” gas, diesel or phase separation water floats
  7. Precision or standard density float
  8. LPG float
  9. Chemical float

Leak Detection Probes

Leak detection probes include a vibration motor integrated into the probe head which pulses every 5 minutes to reduce the effects of stiction on level reading and leak detection, providing readings with higher accuracy.

Model Number Description
FMP-LL3-101 8' digital leak detection probe
FMP-LL3-113 9' digital leak detection probe
FMP-LL3-125 10' digital leak detection probe
FMP-LL3-131 10'6" digital leak detection probe
FMP-LL3-137 11' digital leak detection probe
FMP-LL3-149 12' digital leak detection probe
FMP-LL3-29 2' digital leak detection probe
FMP-LL3-41 3' digital leak detection probe
FMP-LL3-53 4' digital leak detection probe
FMP-LL3-65 5' digital leak detection probe
FMP-LL3-69 5'4" digital leak detection probe
FMP-LL3-77 6' digital leak detection probe
FMP-LL3-81 6'4" digital leak detection probe
FMP-LL3-89 7' digital leak detection probe

Inventory Control Probes

Model Number Description
FMP-LL3-101-I 8' digital inventory control probe
FMP-LL3-113-I 9' digital inventory control probe
FMP-LL3-125-I 10' digital inventory control probe
FMP-LL3-131-I 10'6" digital inventory control probe
FMP-LL3-137-I 11' digital inventory control probe
FMP-LL3-149-I 12' digital inventory control probe
FMP-LL3-29-I 2' digital inventory control probe
FMP-LL3-41-I 3' digital inventory control probe
FMP-LL3-53-I 4' digital inventory control probe
FMP-LL3-65-I 5' digital inventory control probe
FMP-LL3-69-I 5'4" digital inventory control probe
FMP-LL3-77-I 6' digital inventory control probe
FMP-LL3-81-I 6'4" digital inventory control probe
FMP-LL3-89-I 7' digital inventory control probe