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DS206 Blue Green Algae Probe MODBUS Protocol Water Quality Monitoring Sensor

Basic Information
Place of Origin: China
Brand Name: Desun Uniwill
Model Number: DS305
Minimum Order Quantity: 0-100PCS
Price: According to the specific quantity
Packaging Details: carton packaging
Delivery Time: 7-15 working days
Payment Terms: T/T, L/C, D/A, D/P
Detail Information
Product Name: Blue Green Algae Sensor Principle: Fluorescence Method
Measure Range: 0-270, 000 Cells/mL Resolution: 1 Cells/mL
Detection Limit: 300 Cells/mL Housing Material: SS316
Power Supply: 5~12vdc,current <50mA (when Not Cleaned) Output Signal: RS485, MODBUS Protocol
IP Grade: IP68 Deepest Depth: Underwater 10 Meters
High Light:

DS206 Blue Green Algae Probe


Blue Green Algae Probe MODBUS Protocol


MODBUS Protocol Water Quality Monitoring Sensor

Product Description

DS206Fluorescent blue-green algae sensor for water quality monitoring in rivers and lakes RS485, MODBUS protocol 


The online blue-green algae sensor uses the principle of fluorescence method, which is more efficient and faster than the traditional manua counting method, and can be monitored in real time online. The senso has better repeatability and stability. With automatic cleaning brush, it can eliminate air bubbles and reduce the impact of contamination on the measurement, make the maintenance cycle longer, and maintain excellen stability for long-term online use It can play an early warning role on algae reproduction.


★ Digital sensor, RS-485 output, support MODBUS

★ With automatic cleaning brush to prevent contamination and eliminate air bubbles

★ Direct measurement, simpler than traditional manual counting method

★ Continuous online monitoring, real-time control of water quality dynamics


Technical parameter

Product name Blue-green Algae Sensor
model DS206
principle Fluorescence method
Range 0-270, 000 cells/mL
Detection limit 300 cells/mL
Resolution 1 cells/mL
Linearity R2>0.99
temperature range 0~ 50°C
Protection level Ip68
Sensor interface Support RS-485, MODBUS protocol
Installation Input type,
Power information DC 5~12V, current <50mA
size Φ45*175.8mm
Probe cable length 10 meters (default), can be customized
Housing material SS316
Self-cleaning system Have


Calibration instructions


1,Calibration of blue-green algae sensors: The blue-green algae sensor software (see the modbus manual) supports 2-point calibration. The more common environmental research dye, rhodamine B, can be used in sensor calibration.


  • First take 0.1g of rhodamine B solution into 1000mL reagent bottle A, then add DI water or distilled water to 1000mL and shake well.
  • Take 1mL of the above solution into 1000mL reagent bottle B, and then add DI water or distilled water to 1000mL and shake well. The solution concentration of reagent bottle B is 100 ppb.
  • The prepared solution should be used within 24 hours.


Rhodamine B shows that the fluorescence intensity is inversely proportional to temperature. Use 100 ppb rhodamine B standard solution. To properly set the sensor to ensure the sensitivity of algae blue-green algae at 20 ° C, enter the calibration value according to the temperature standard corresponding to the table below. (The table below shows algae blue-green algae as a function of temperature approximately equal to 100 ppb rhodamine B)


Temp, cells/ml
26 54600
27 52471
28 51376
29 49670
30 47641
31 45276
32 43258
33 40711
34 38905
35 37298
36 34875
37 33370

Note: The calibration using rhodamine B standard solution is only an approximate value. To ensure accurate readings, the fluorescence readings obtained on site must be linked to the results obtained from the extraction analysis of the above samples. Yushan used Rhodamine B (Item # 70301027) from Keystone.

Warning: Rhodamine B is listed as a substance that may cause carcinogenesis / induction of organism mutations. Gloves must be worn during operation.

Maintenance methods and common problems Maintenance schedule and method

I. Maintenance schedule

Online blue-green algae sensor with automatic cleaning brush can be automatically cleaned without frequent cleaning.


Maintenance task Recommended maintenance frequency
Calibrate the sensor (if required by the competent authority) According to the maintenance schedule required by the competent authority

2. Maintenance method Sensor maintenance

  • External surface of the sensor: Clean the external surface of the sensor with tap water. If debris remains, wipe it with a moist soft cloth. For some stubborn dirt, you can add some household washing solution to the tap water to clean it.
  • Check the cable of the sensor: the cable should not be tightened during normal work, otherwise the internal wires of the cable will be easily broken and the sensor will not work properly.

3) Check whether the measurement window of the sensor is dirty and whether the cleaning brush is normal.

  • Check the sensor's cleaning brush for damage.
  • 18 months of continuous use, need to return to the factory to replace the dynamic sealing device.


Frequently Asked Questions


Error Possible reason solution

The operation interface cannot be connected or the measurement result is not


Controller and cable

connection error

Reconnect controller and



Cable failure

Please contact us

The measured value is too high, too low or the value is

continuously unstable

The sensor window is

attached by a foreign object

Cleaning the sensor window


Damaged sensor sponge Replace the sensor sponge


Cable Definition

Power information

The power supply must be DC 5-12V +/-5%, current <50mA

DS206 Blue Green Algae Probe MODBUS Protocol Water Quality Monitoring Sensor 0

Cable information

4 wire AWG-24 or AWG-26 shielding wire. OD=5mm


1, red line - power supply (VCC)

2, white line - 485 data _B (485_B) 3, green line --- 485 data _A (485_A) 4, black line --- ground (GND)

5, bare line shielding layer

About Us

Xi'an Desun Uniwill Electronic Technology Co., Ltd (Hereinafter referred to as Disen Sensing Company) is located in Xi'an High-tech Development Zone. It is a high-tech company integrating production, R&D, sales and engineering services. Relying on Xi'an's rich high-tech resources, we have carried out technical cooperation with many universities and scientific research institutions, constantly breaking through technical barriers, improving product performance, and using leading technology to provide high-quality products for the water quality monitoring industry.

We launched a wireless water quality monitoring solution based on the current rapid development of the Internet of Things technology, combining smart terminals and traditional display units through wireless transmission to achieve real-time dynamic water quality monitoring functions such as data cloud display, remote cloud control, and upper and lower limit alarms.


Contact Details

Phone Number : +86 181 8242 9986

WhatsApp : +8618182429986