Dissolved Oxygen Probe AT-SB-PROBE-DO-T-C1
Datasheet
1. Introduction
"The SENSBLUE RS-485 Dissolved Oxygen Probe (AT-SB-PROBE-DO-T-C1) is designed for the aquaculture industry. It offers stable online monitoring, providing excellent performance compared with traditional sensors. As a fluorescence-based dissolved oxygen sensor, it requires no membrane or electrolyte and features strong anti-interference capabilities. It does not require frequent calibration, has no oxygen consumption, and no flow rate limitations. Additionally, it includes automatic temperature and gas pressure compensation, a fast reaction speed, and a long service life. This makes it an economical and convenient choice for the real-time dynamic monitoring of oxygen levels in aquaculture."
2. Features
- Digital sensor, RS485 output, support MODBUS
- No electrolyte required, strong anti-interference, no need for frequent calibration; no oxygen consumption, no flow rate limit;
- Built-in temperature sensor, automatic temperature compensation;
- Tailor-made for the breeding market, with cost-effective performance
3. Technical Specifications
| Measurement principle | Fluorescence method |
| Range | 0-20mg/L or 0-200% saturation |
| Accuracy | ±3% |
| Casing material | 316L(KWS-630) Titanium alloy(KWS-630T) |
| Max water depth | 30m |
| Response time | 60s |
| Temperature range | 0-50℃ |
| Sensor interface | RS-485, MODBUS protocol |
| Power consumption | -0.1W (recommended power supply: DC9-24V, current>50mA) |
| Assembly | M22*1.5 (optional accessories can be converted to
NPT3/4 thread), immersion installationa |
| Sensor dimensions | Φ22mm*152.7mm |
| Probe cable length | 10 meters (default), customizable |
| Calibration | One or two-point calibration |
| Fluorescent cap life | Guaranteed to use for one year (under normal use) |
4. Dimensions and Wiring
5. Installation and Pinouts
5.1 Installation
(1) Removing the protective cover Prior to installation, please remove the rubber protective cap from the front of the dissolved oxygen sensor and keep it in a safe place.
(2) Wiring and power supply:
1. The sensor's watertight connector, and the cable (or female connector) must be tightly screwed together to prevent water ingress.
2. Do not use the sensor cable to suspend the sensor. It is recommended to install a cable protective sleeve to ensure the connection remains powered and watertight.
3. Before switching on the power, ensure that the supply voltage and wiring sequence are correct.
(3) Sensor installation
1. The unit features an M22*1.5 rear thread (optional accessories are available to convert this to an NPT 3/4" thread) for fixed or shell-clamp installation. (Note: It is recommended to install the sensor with the electrode facing downwards).
2. To account for fluctuating water levels, it is recommended to install the sensor at least 30cm below the lowest water line to avoid prolonged exposure to air during measurement.
3. The sensor must be securely fixed to prevent probe damage caused by water flow or other external factors.
5.2 Pinouts
| Pinouts | |
|---|---|
| 1 - Pin 12-24V DC | 4 - RS485 B- |
| 2 - GND | 5 – NA |
| 3 - RS485 A+ | 6 - NA |
| 7 - NA | |
6. Calibration
6.1 Calibration method
The dissolved oxygen sensor supports single-point (typically the 100% saturation point) or two-point calibration. The calibration parameter uses a percentage scale (expressed as a decimal, e.g. 0.96 for 96%). Single-point calibration primarily adjusts the K-value (slope), whereas two-point calibration adjusts both the K and B values (slope and offset).
6.2 Standard solution preparation
1.) Zero-point standard solution To prepare the zero-point standard solution, pour 200ml of distilled water into a beaker. Gradually add anhydrous sodium sulfite while stirring until the solution is saturated (i.e., when it can no longer dissolve and solid crystals begin to appear). The resulting mixture is your zero-point standard solution.
2.) 100% oxygen environment Pour 200ml of pure or distilled water into a beaker. Use a small aerator to oxygenate the water thoroughly for 10–15 minutes (larger volumes of water will require more time).Note: If on-site conditions are restricted, the sensor can be cleaned and a saturation-point calibration can be performed in open air, though accuracy may be slightly reduced.
6.3 Manual calibration calculation of K and B example (taking 2-point calibration as an example)
First, restore the user calibration data to the default settings: K=1, B=0 (refer to the Modbus documentation for details). Clean the sensor and place it in a 100% oxygen environment (air). Read the dissolved oxygen value and wait for the data to stabilize. The value should be close to 1 (i.e. 100% saturation), for example, 0.96; record this value as Y. Wash the sensor again and place it in the zero-point standard solution, ensuring the front end of the sensor is completely immersed. Read the dissolved oxygen value and wait for the data to stabilize at a value close to 0, for example, 0.015; record this as X. Calculate the new K and B values using the following formulas:
K = 1 - 0 / Y – X B = - K x X
Finally, write the calculated K and B values into the sensor registers (see the Modbus documentation for further details).
6.4 Required equipment and materials
Anhydrous sodium sulfite powder; Deionized water or distilled water (such as Watsons distilled water); Beaker, gloves, stirring rod, small aerator.
7. Maintenance schedule and methods
7.1 Maintenance cycle
Different from the electrochemical principle of dissolved oxygen probes, fluorescence dissolved oxygen probes do not consume oxygen, have no filling fluid, etc., and do not require frequent maintenance. Normal cleaning and user calibration are sufficient.
| Maintenance tasks | Maintenance cycle (cleaning, calibration) |
| Cleaning the sensor | Recommended every 2~3 weeks (extended for automatic cleaning brushes. Shortened for those without cleaning brushes and large biomass) |
| Inspecting the sensor and fluorescent cap for damage | Check every 30 days |
| Replacing the fluorescent cap | Replace once a year |
| Calibrating the sensor | Recommended every 30 days for frequent use; before each use for occasional use; or adjust according to actual working conditions on site. |
Note: The maintenance frequency in the above table is only a suggestion. Please ask maintenance personnel to maintain the sensor according to the actual use of the sensor; however, it is recommended to replace the fluorescent cap once a year.