PLI DIGITAL™ Portable Liquid Level Gauge


With all of the features of the original PLI, the American Bureau of Shipping (ABS) type approved PLI Digital™ can take a reading from cylinders in poor condition, or suffering from a layer of rust.

It also has an in-built thermometer (showing readings in both Celsius [°C] and Fahrenheit [°F]), and an easy to read digital display. It features a one-button set-up function for faster cylinder detection, and a smart plug, which enables the signal strength to be monitored by an audio signal from an internal speaker.

ABS Approved Product

The PLI DIGITAL can be used on cylinders, pipework, and any single skinned holding vessel with up to 25mm thick walls.

It indicates the level of oil or water in a container or tank. The PLI DIGITAL™ gives accurate results by generating an ultrasonic sound wave that travels through the container and into the fluid or liquified gas.

The pulse responds differently to the presence or absence of liquid, which helps indicate to the client the level of liquid they are dealing with.

There is no reduction in health and safety levels, and the risk of gas leaks during servicing is eliminated as cylinders remain active and in situ.

  1. Wipe clean the cylinder in the area that you are going to place the sensor. Make sure this is in an area known to be ABOVE the liquid level. Apply couplant to the sensor.
  1. Place the sensor on the cylinder making sure that the white dot is at the top. The reading may show anything between 5 and 12. To calibrate the PLI DIGITAL™ unit, press the SET button. The screen will say SETTING and the display bar graph will rise or fall until it reaches 10. You will hear a double bleep and the screen will say SET.
  1. Place the sensor in an area known to be BELOW the liquid level. The meter should read towards 0 but not below 0.
  1. Move the sensor upwards towards the liquid level. The meter will start to move towards 10. When the whole of the sensor footprint is above the liquid level, the meter will read 10. When the sensor is at the liquid level gauge, the reading will show a value of between 10 and 0.

What you are looking for after this process is a large change in value between a reading below the liquid level and one above the liquid level.

A reading of approximately 5 at the liquid level is suggested.

The complete  PLI DIGITAL™ includes:

  • The PLI DIGITAL™ liquid level gauge
  • Protective leather case
  • Three-section telescopic extension arm
  • Foam-lined red polymer carry case
  • Full operating instructions
  • 125ml bottle of couplant
  • Piezoelectric sensor
  • 8 x AA batteries

PLI Digital™ can take a reading from cylinders in poor condition, or suffering from a layer of rust.

The PLI Digital™ can also find the level of liquid or liquefied gas in:

  • Fire extinguisher cylinders
  • Metal cylinders
  • Pipework
  • Any single skinned pressurised vessel
  • Liquid storage tanks
  • Accuracy ±1.5mm
  • Large graphic display
  • Automatic rapid set up
  • Temperature gauge in both °C (Celcius) and °F (Farenheight) to enable fast weight calculations
  • Smart plug in to enable signal strength to be monitored as an audible signal from the internal speaker
  • Power boost facility for cylinders in poor condition
  • Cylinder wall thickness selector for thick (>4mm) or thin (<4mm) walled cylinders
Weight –
  • Operational weight – 650g
  • Shipping weight – 2.5kg
Unit –
  • Dimensions – 210 x 130 x 55mm
  • Weight – 540g (including batteries and leather case)
Sensor –
  • Dimensions – 95 x 60 x 38mm
  • 5m cable
  • Magnetic clamp for hands-free use
  • Temperature range from -10°C to 50°C plus

Please note – when the unit is being used to determine the level of liquid CO₂, an ambient temperature of over 27°C will not give a result, as CO₂ above this temperature (27°C) changes state, from a liquid to a gas.

Telescopic Extension Arm –
  • Length – 94cm
Power Supply and Batteries –
  • 4 x AA Batteries
  • Battery life – 20 hours nominal
Carry Case –
  • Dimensions – 450 x 370 x 100mm
ABS Manufacturing Assessment
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PLI Digital ABS Product Type Approval
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ISO 9001:2015

NATO Stock Number 6680-99-155-5945

NCAGE Number U0B22

IIMS Corporate Membership Number C508

FPA Membership Number 27135

NFPA Membership Number 2800960

International Customer Base and Exceptional Service.

Accreditations and Affiliations

ABS Type Approved Equipment

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    Designed and Manufactured in Great Britain

    We are proud to be British based designers and manufacturers of world-leading ultrasonic water integrity testers, liquid level indicators and non – destructive test equipment.