RS-485 Turbidity Probe AT-SB-PROBE-T-P
Datasheet
1. Introduction
SENSBLUE RS-485 Turbidity Probe AT-SB-PROBE-T-P is used in environmental water quality monitoring, acid/alkali/salt solutions, chemical reaction processes, and industrial production processes. It can meet the requirements of online pH measurement for most industrial applications.
2. Features
- 90° angle scattered light principle, built-in temperature sensor
- Support RS-485, Modbus/RTU protocol
- Optical fiber structure, strong resistance to external light interference
- Infrared LED light source with high stability
- IP68 protection, water depth within 20 meters
- Convenient, fast, stable and easy to maintain
3. Technical Specifications
| Model | KWS-960 | |
|---|---|---|
| Measuring Range | Turbidity PPR AT-SB-PROBE-T-P | |
| Principle | Light scattering method | |
| Range/Resolution | 0～20.00NTU | 0.01NTU/0.1℃ |
| 0～200.0NTU | 0.01NTU/0.1℃ | |
| 0～1000.0NTU | 0.1NTU/0.1℃ | |
| Precision | ±3% or ±1.5NTU(0～20.00NTU) ±3% or ±2NTU(0～200.0NTU) ±5% or ±3NTU(0～1000.0NTU) | |
| Response Time (T90) | ＜60s | |
| Lowest Detection Limit | 0.01 (0-20NTU) | |
| 0.3NTU | ||
| Calibration Mode | Two-point calibration | |
| Temperature Compensation | Automatic temperature compensation (Pt1000) | |
| Output | RS-485 (Modbus/RTU) | |
| Working Conditions | 0～50℃，<0.2MPa | |
| Storage Temperature | - 5 ～ 65 ℃ | |
| Installation | Immersion mount with 3/4NPT pipe thread | |
| Cable Length | 5 meters, other lengths can be customized | |
| Power Consumption | 0.2W@12V | |
| Power Supply | 12～24VDC | |
| Protection Grade | IP68 | |
4. Dimensions
Note: The sensor joint is M16-5 core waterproof joint male head
5. Installation and Pinouts
5.1 Installation
Installation distance requirements: keep above 5cm with side wall and above 10cm with bottom.
| Pinouts | |
|---|---|
| 1 - Pin 12-24V DC | 4 - RS485 B- |
| 2 - GND | 5 – NA |
| 3 - RS485 A+ | 6 - NA |
| 7 - NA | |
6. Maintenance
6.1 Use and maintenance
a) Maintenance schedule
The cleanliness of the measuring window is very important for maintaining accurate readings.
| Maintenance task | Recommended maintenance frequency |
|---|---|
| Calibrate sensors
(if required, by the competent authority) |
According to the maintenance schedule required by the competent department |
b) Maintenance method
- Sensor outer surface: Clean the outer surface of the sensor with tap water. If debris remains, wipe it with a soft, wet cloth. For stubborn dirt, you can add some household detergent to the tap water, but rinse thoroughly with clean water afterwards.
- Check the cable of the sensor: The cable should not be tightened while the sensor is operating, as this may cause the internal wires to break and prevent the sensor from functioning properly.
- Check the sensor’s measurement window to see if there is any dirt. Use a normal cleaning brush if there is some.
c) Matters that require attention
- The probe contains sensitive optical and electronic components. Make sure the probe is not subjected to severe mechanical impact. There are no components inside the probe that need to be maintained by the user; open it only when specifically instructed by ATRONIA, as opening it may damage the internal components.
d) Sensor’s Calibration
- Zero calibration: Take an appropriate amount of zero‑turbidity solution in a large beaker. Place the sensor vertically in the solution, ensuring that the front end of the sensor is at least 10 cm from the bottom of the beaker. Perform the zero calibration after the reading has stabilized for 3 minutes. For instructions, refer to the appendix.
- Slope calibration: Place the sensor probe in the standard solution, ensuring that the front end of the sensor is at least 10 cm from the bottom of the beaker. Perform the slope calibration after the reading has stabilized for 3 to 5 minutes. For instructions, refer to the appendix.
6.2 Frequently Asked Questions
| Problem | Probable cause | Solution |
|---|---|---|
| The operating interface cannot connect or does not display the measurement results | The measured value is too
high, too low, or the numerical value remains unstable. |
Reconnect the controller and cable |
| Cable failure | Please contact us. | |
| The measured value is too
high, too low, or the numerical value remains unstable. |
The sensor window is attached to the external object | Clean the window surface of the sensor |
7. Appendix data communication
7.1 Data Format
The default data format for Modbus communication is: 9600, n, 8, 1 (baud rate 9600bps, 1 start bit, 8 data bits, no parity, 1 stop bit).
7.2 Information Frame Format
(xx for one byte).
a) Read data instruction frame
07 03 xx xx xx xx xx xx
Address Function code Register start address Number of registers CRC check code (low byte first)
b) Read data response frame
07 03 xx xx xx xx xx xx
Address Function code Bytes Response data CRC check code (low byte first)
c) Wriite data instruction frame
07 06 xx xx xx xx xx xx
Address Function code Register address Read-in data CRC check code (low byte first)
d) Write data response frame (same data command frame)
07 06 xx xx xx xx xx xx
Address Function code Register ddress Read-in data CRC check code (low byte first)
7.3 Register address
| Register address | Designation | Explain | Number of registers | Access mode |
|---|---|---|---|---|
| 40001 (0x0000) | Measured value + temperature | 4 double-byte integers, namely, the measured value, the number of decimal places of the measured value, the temperature value, and the number of decimal places of the temperature value. | 4 (8 bytes) | Read |
| 44097
(0x1000)) |
Zero calibration | The 0-20NTU range is calibrated in 0-10NTU turbidity solution, and the written data is the actual value of the standard solution × 100; the 0-100NTU range is calibrated in 0-20NTU turbidity solution, and the written data is the actual value of the standard solution × 10; the 0-1000NTU range is calibrated in 0-200NTU turbidity solution, and the written data is the actual value of the standard solution × 10; the read data is the zero-point offset. | 1(2 bytes) | Write/Read |
| 44101
(0x1004) |
Slope calibration | The 0-20NTU range is calibrated in 10-20NTU turbidity solution, and the written data is the actual value of the standard solution × 100; the 0-100NTU range is calibrated in 20-100NTU turbidity solution, and the written data is the actual value of the standard solution × 10; the 0-1000NTU range is calibrated in 200-1000NTU turbidity solution, and the written data is the actual value of the standard solution × 10; the read data is the slope value × 1000. | 1(2 bytes) | Write/Read |
| 44113
(0x1010) |
temperature correction | When calibrated in solution, the written data is the actual temperature value × 10; the read data is the temperature calibration offset × 10. | 1(2 bytes) | Write/Read |
| 48195
(0x2002) |
Sensor
address |
The default is 7, and the write data range is 1-255. | 1(2 bytes) | Write/Read |
| 48196
(0x2003) |
Baud rate | Default is 9600. 0-9600, 1-19200. | 1(2 bytes) | Write/ Read |
| 48225
(0x2020) |
Reset sensor | The calibration value is restored to the default value, and the written data is 0. Note that the sensor needs to be calibrated again after being reset before it can be used. | 1 (2 bytes) | Write |
7.4 Command example
a) Start measurement instructions
Function: Obtain the turbidity value and temperature of the measuring probe; the unit of temperature is Celsius, and the unit of turbidity is NTU.
Request frame: 07 03 00 00 00 04 44 6F
Response frame: 07 03 08 01 02 00 01 00 B0 00 01 94 B4
Example of reading:
| Turbidity value | Temperature scale |
|---|---|
| 01 02 00 01 | 00 B0 00 01 |
For example: turbidity value 01 02 means hexadecimal reading turbidity value, 00 01 means turbidity
value with 1 decimal point, converted to decimal value 25.8.
The temperature value 00 B0 represents the hexadecimal reading temperature value, and 00 01
represents the temperature value with a decimal point converted to a decimal value of 17.6.
b) Calibration instructions
Zero calibration
Function: Set the zero-calibration value of the turbidity of the sensor; here the zero calibration is
performed in zero turbidity water;
Request frame: 07 06 10 00 00 00 8C 6E
Response frame: 07 06 10 00 00 00 8C 6E
Slope calibration
Function: Set the slope calibration value of the sensor turbidity.
For sensor with a range of 0 to 1000 NTU and 0 to 100 NTU, the slope calibration example is as
follows (calibrated in 1000 NTU standard solution, the written value is 1000x10, i.e. 0x2710):
Request frame: 07 06 10 04 27 10 D6 91
Response frame: 07 06 10 04 27 10 D6 91
For sensor with a range of 0 to 20 NTU, the slope calibration example is as follows (calibrated in
20 NTU standard solution, the written value is 20x100, i.e. 0x07D0):
Request frame: 07 06 10 04 07 D0 CF 01
Response frame: 07 06 10 04 07 D0 CF 01
c) Set the device ID address:
Role: set the MODBUS device address of the electrode;
Change the device address 06 to 01. The example is as follows
Request frame: 07 06 20 02 00 01 E2 6C
Response frame: 07 06 20 02 00 01 E3 6C
7.5 Error response
If the sensor does not execute the upper computer command correctly, the following format information is returned:
| Definition | Address | Function Code | CODE | CRC check |
|---|---|---|---|---|
| data | ADDR | COM+80H | xx | CRC 16 |
| Number of bytes | 1 | 1 | 1 | 2 |
a) CODE: 01 – Functional code error
03 – Data error
b) COM：Received function code