SA9L: Dual-Wavelength Detecting Sensor

The newly redesigned SA9L series sensors enable reliable low-cost, accurate measurements of parameters like: COD, BOD, TOC, DOC, UV254/SAC254, NO3, Color, Turbidity etc.
Utilizing state-of-the-art LED light sources mated to highly sensitive photodetectors, the SA9L is a Dual-Wavelength Absorption Detecting Sensor designed for long-term, low-drift monitoring of water quality.
All SA9L sensors have an embedded temperature sensor for automatic temperature compensation (ATC) to ensure stable light emission from the LEDs.
The two wavelengths are selected according to the specific parameters and application requirements.

There are basically three kinds of sensors. For SA9L, one wavelength represents the primary target parameter, such as COD and the second wavelength represents the reference parameter like Turbidity or SS (suspend solid).
Built-in corrections for Turbidity minimize interference of suspend solid in water environments.
For example, to measure COD, 254 nm corresponds to absorption by dissolved organic matter (DOC) and 360 nm is used to compensate for turbidity/SS.
Automatic turbidity/SS compensation is used to calculate organic matter concentration expressed as COD by the Beer-Lambert law.

For SA9LN, one wavelength represents the target parameter Nitrate (NO3-) and the second wavelength represents the reference of Turbidity or Suspend Solid.
For SA9LC, one wavelength represents the target parameter Color (Hazen-t) and the second wavelength represents the reference of Turbidity/SS.

Following diagram for the relation between wavelengths and parameters.

The SA9L Sensors are available with several optical paths.
Standard path lengths cover most applications: 1mm, 2mm, 5mm, 10mm.
Different path length meet the requirements of different parameters and measuring ranges.

The SA9L adopts extremely durable sapphire windows that are very resistant to abrasion.
An embedded wiper which can be programmed by a controller for automatic cleaning is helpful to remove the buildup of materials coating the windows.

The standard probe is totally submersible with 316L stainless steel housing and there is an optional Titanium housing for special applications like sea water.
Such features create a sensor that is low maintenance even under harsh conditions.
Although in-situ installations in tanks and open channels is recommended, bypass sampling flow cells may be used when in-situ mounting is not possible.

The SA9L sensors seamlessly connect to Delta-Phase’s family of General Display & Controllers (GDC) by RS485/Modbus communication.
The GDCs offer flexible calibration and configuration to the sensor. Setup is simple and quick.
The GDCs have analog outputs, full function of control and data logging, multiple digital interfaces including Modbus & Bluetooth.
As the protocol is open, the SA9L can work with other terminals from third parties and may be interfaced to a PC.
Connection to a PC is facilitated with Delta-Phase ViewTM software, The Delta-Phase ViewTM features powerful configuration/calibration function of the sensor and more extensive data logging than the GDC alone.