Posted in | Level Sensors

Range of Optomax Digital Liquid Level Sensors: A Restricted Space Sensing Solution

The Optomax Digital liquid level switches are suitable for applications with restricted space that require a tiny, low power and economical sensing solution.

The liquid level microcontroller-based sensor is solid state, including an infra-red LED and phototransistor which are optically coupled by the tip when the sensor is in air. When the sensing tip is immersed in liquid, the infra-red light escapes, thereby making the output change state. The sensor can detect the absence or presence of nearly any liquid type; water or oil based. It is not sensitive to ambient light, and is not impacted by small bubbles when in liquid or by foam when in air.

The TTL compatible push-pull output can sink and source up to 100 mA at a supply voltage range of 4.5 to 15.4 Vdc and can be configured to output a low or high signal when in either a dry or wet state. A fail-safe PWM option is also available with a supply voltage range of 4.5 to 5.5 Vdc.

The sensors have housing options for external or internal sensor mounting and for use in two operating temperature ranges; standard (-25 to 80 °C) or extended (-40 to 125 °C). Two chemically resistant housing materials, Polysulfone, the regular choice for a majority of applications or Trogamid, which is commonly used in food and beverage applications, are available.

Part Numbering Guide

Specifications

Technical specifications

. .
Supply Voltages (Vs) 4.5 to 15.4 Vdc
or 4.5 to 5.5 Vdc (PWM Output)
Supply Current (Is) 2.5 mA max. (Vs = 15.4 Vdc)
Output Sink and Source Current (Iout) 100 mA
Operating Temperatures Standard: -25 to +80 °C
or Extended: -40 to +125 °C
(Above +85 °C Trogamid is suitable for use in water based liquids, oil based liquids can cause deformation of the sensing tip and must be tested for compatibility)
Storage Temperatures Standard: -30 to +85 °C
or Extended: -40 to +125 °C
Housing Materials Polysulfone (Standard)
or Trogamid
Sensor Termination 24 AWG, 250 mm PTFE wires, 8 mm tinned
Operating Pressures 0 to 20 bar (M10x1 thread)
or 0 to 7 bar (All other threads)

 

Output Values

Output Voltage (Vout): Iout = 100 mA
Output High Vout = Vs – 1.5 V max
Output Low Vout = 0V + 0.5 V max
PWM Output  
  Duty Cycle in Air 25% ± 10%
  Duty Cycle in Liquid 75% ± 10%
Frequency 2 kHz ± 10%

 

Outline Drawings

Sensor mounted from inside vessel (M10x1 thread)

Sensor mounted from outside vessel (M12x1,1/2″ SAE and 1/4″ NPT threads)

Electrical Interface

Wire Designation
Red Vs
Green Output*
Blue 0V

*See part numbering guide for output logic

Features and Benefits

Features

The key features of the Optomax Digital Liquid Level Sensors are as follows:

  • Wide supply voltage range
  • Reverse polarity, ESD and transient over-voltage protected
  • Push-pull output, capable of sinking or sourcing up to 100 mA, can directly drive small loads
  • Standard and extended temperature ranges available
  • Optional fail-safe PWM output
  • Trogamid or Polysulfone housing material options
  • External or internal mounting options
  • High pressure option available

Benefits

The key benefits of the Optomax Digital Liquid Level Sensors are as follows:

  • Very robust permitting use in a broad range of chemicals and fluids
  • Solid state with any moving parts to cause unreliability
  • Rapid response time
  • Small in size so enables installations even in applications where space is limited
  • Repeatable switching point
  • Can detect small quantities of liquid when positioned correctly, perfect for leak detection
  • Integrated output delays available on request for applications where sloshing results in intermittent switching

Operating Principle

When in air the infrared light is reflected back to the detector

When in air the infrared light is reflected back to the detector

When in liquid the infrared light is refracted and the output switches

When in liquid the infrared light is refracted and the output switches

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