LT-739B Ultra-Low Turbidity Sensor (0.001–40.00 NTU) | InfraRed LED

860nm InfraRed LED Ultra-Low Turbidity Sensor.

ISO-7027 Compliant inline turbidimeter that uses Warm White LED light sources that offers a range of 0.001–40.00NTU with Ultra-Low Resolution.

  CE Mark




The LT-739B is a proprietary inline turbidimeter that offers a range of 0.001–40.00NTU with ultra-low resolution. This sensor has a unique flat surface distal end in a quartz glass plate, allowing for extending cleanliness and easy maintenance & prevention of air bubble interference. The ST-739B is ISO-7027 compliant as it utilizes 860nm InfraRed LED light sources for optimal accuracy and performance in a wide range of turbidity water samples. It also uses 90º surface scatter configuration, offered in two flow assembly installation formats (FR-100 Flow Reservoir or FT-100 Inline Tee). Powered by a 24VDC/2W power supply and offers both 4–20mA & RS-485 Modbus output signals. When clean, the unique Pyxis Lab® sensor design offers a calibration stability of <0.02NTU for up to 1-year of operation with no need for calibration. Additionally, the ST-739B can be wirelessly accessed via Bluetooth® for Diagnostics, Cleaning, & Calibration on uPyxis® when used with the MA-CR Bluetooth® Adapter.



  • 0.001–40.00NTU Range
  • ISO-7027 Compliant
  • Offers Both 4–20mA & RS-485 Modbus Output Signals
  • InfraRed 860nm LED Light Source


Item LT-739B
Part Number 53225
Light Source (LED) InfraRed 860nm
Range (NTU) 0.001-40.00
Accuracy Using FR-100 ±0.005NTU or 2% <40NTU
±0.01NTU or 2% >40NTU
Accuracy Using FT-100 ±0.01NTU or 2% <40NTU
±0.02NTU or 2% >40NTU
Repeatability Using FR-100 ±0.001NTU or 0.5% <40NTU
±0.01NTU or 1% >40NTU
Repeatability Using FT-100 ±0.002NTU or 1% <40NTU
±0.02NTU or 1% >40NTU
Calibration Stability <0.02NTU/Year Drift
Assuming Sensor is Clean
Power Supply 22-26VDC, Power Consumption – 1.5W
Outputs Isolated 4-20mA Analog
Isolated RS-485 Modbus Digital
Wireless Access Bluetooth® Enabled when used with MA-CR or PowerPACK Adapters
Installation FR-100 Flow Reservoir Assembly
FT-100 Inline Tee with 1.5″ NPT Glue & Thread
Weight 800g (2.1lbs – Sensor Only)
Operational Pressure Up to 100psi (6.9Bar)
FR-100 Reservoir Atmospheric Pressure
FT-100 Inline Tee up to 100psi (6.9Bar)
Operating Sample Temperature 1-50 °C (33.8-131 °F)
Sample Flow Rate LT-73X Series = 0-40L/min (0-10.6 GPM)
FR-100 = 200-400mL/min
FT-100 = 0-40L/min (0-10.6 GPM)
Wet Material 304SS / PVC & Polycarbonate
Cable Length Standard MA-4.9CR (8Pin Adapters – 4.9ft)
Flying Lead MA-1.5CR (8Pin Adapters/Flying Leads – 1.5ft)
Extension Cables Available
Rating IP67
Regulation CE / RoHS
Dimension 189mm (7.4in) L x 36mm (1.44in) D

Support Documents

LT-73X Series User Manual V1.18

LT-73X Series Ultra-Low Turbidity Sensor Data Sheet


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