Radar Level Gauge For Monitor Tank Level, Working Humidity 0~95% Supply Voltage 9~24V

1.Introduction

1.1 Product Overview

KWL801B-RS485 radar level sensor conforms to the standard specifications outlined in national standard DB50/T 826-2017 for level meters. Its core component is designed with a fully sealed IP68 waterproofing.

The maximum measurement range of the product extends up to 40 meters, with a minimal blind spot of less than 6 cms.

Due to its higher frequency and broader bandwidth, it achieves superior accuracy. Additionally, the product includes a fixed bracket for installation.

1.2 Detection principle

Radar level sensor is based on the principle of time domain reflection (TDR). The electromagnetic pulse propagates along the cable or probe with the speed of light. When it meets the surface of the measured medium, part of the pulse of the radar level meter is reflected to form an echo return to the pulse transmitter along the same path, and the distance between the transmitter and the surface of the measured medium is In direct proportion as the propagation time of the pulse, hence the height of the level is calculated.

2.Feature

• Based on the self-developed CMOS millimeter-wave RF chip
• More compact RF architecture
• Higher signal-to-noise ratio
• Smaller dead zone
• 5GHz working bandwidth
• Higher measurement resolution and measurement accuracy
• Less influence by the interference in the installation environment
• More convenient of installation and
• Modern design of integrated flat antenna

3.Technical Specifications

4.Wiring Instructions

5.Dimension

6.Installation instructions

6.1 Inspection before installation

(1) Take the sensor out of the packaging box, carefully check the packing list according to the instruction manual, and check whether the equipment accessories are complete .

(2) Carefully read the product instruction manual and product certificate .

(3) Check whether there is any damage to the appearance of the instrument, especially whether the main unit is intact, and be careful to place the main unit properly to prevent it from being knocked over.

6.2 Radar level sensor installation

6.2.1 Check before installation

Please check before installing the sensor as follows:

Whether there are trees or other debris above the medium at the installation site.

Whether the mounting bracket is installed horizontally.

When the mounting bracket cannot be installed horizontally, you need to adjust the bracket according to gradienter on the surface of the sensor to make sure the sensor is in a horizontal position.

6.2.2 Installation

(1) Ensure that the sensor is perpendicular to the medium surface.

(2) Avoid the transmitting beam from irradiating interference objects and generating false echoes.

See the following for typical working conditions:

Installation of upper thread Installation of lower thread

Ensure that the radar level meter is installed perpendicular to the medium surface.

Inclination will weaken the received signal amplitude and affect normal ranging.

Attention:

Try to keep the sensor fixed to avoid jitter when installing, and keep the surrounding environment as open as possible.

1. The distance between the sensor and the medium surface is higher than 30cm to ensure that the front face of the sensor (antenna) is perpendicular to the measuring medium.

2. The distance between the sensor and the edge of the tank, the edge of the pool, the edge of the river dam and the edge of the pool is greater than 0.5 meters;

3. Select the position of the water surface with small fluctuations to install the module (try not to install in the water injection port, outlet and other water surface with large fluctuations, the greater the water surface fluctuation, the worse the measurement accuracy)

​7.MODBUS-RTU communication protocol

7.1 MODBUS protocol

1. Communication protocol hardware interface parameters

The sensor uses serial port communication, and the default parameters are as follows :

Timeout between frames 50ms.

2. Communication protocol format

The water level gauge communicates externally using the Modbus RTU communication protocol. Each complete data frame includes: address field, Function Code, data, and checksum. The checksum is the CRC16 check data of the data frame, with the low byte preceding the high byte. The default factory address for the sensor is 0x7F.

Request command format and radar reply data format are described as follows:

(1) Query parameter format: Function Code 0x03

Request:

Reply:

N: numbers of registers

(2) Query parameter format: Function Code 0x04

Request:

Reply:

N: numbers of registers

(3) Set parameter format: Function Code 0x10

Request:

Reply:

N: numbers of registers

3. Register Address Summary Table

Note: The Register Address and data type of some parameters can be modified by the host computer software. After modifying the Register Address or data type, the corresponding Modbus operation instructions will also change accordingly, such as: The default instruction to read the empty height is 0x 7F 04 0A 0F 00 02 48 0E. If the register of the empty height is modified to 00 01, the instruction to read the empty height is changed to 0x 7F 04 00 01 00 02 2A 15.

4. Communication protocol command description

Note:

a. The default Device Address is 0x7F;

b. The float type data in the data adopts IEEE754 binary floating point arithmetic standard, the low 16 bits in the first (CDAB);

c. In the following example, the Register Address corresponding to each parameter is the default address. If the address of the register is modified by the host computer, the Register Address in the Modbus operation instruction should be changed accordingly;

d. In the following example, the data definition (data type/unit) of each parameter is parsed according to the default configuration. If the data definition (data type/unit) is modified through the host computer, the data reading and parsing should be modified accordingly;

7.2 Query data instruction: Function Code 0x04

7.2.1 Query measurement results - level (i.e. installation height - air height)

Request command:

Reply data:

Data definition: The default data type is float(little16) data, the default unit is meters (m), the data length is 4 bytes, and the lowest 16 bits are in the first.

Error code:

① When the installation height is not set, the level cannot be calculated, and the output 0xFC FC FC FC ;

② When the measurement results exceed the range, output 0xFF FF FF FF;

③ When the sensor is in the blind area, output 0xFE FE FE FE;

④ When the sensor echo energy is insufficient, the output 0xFD FD FD FD;

Example 1:

Request: 7F 04 0A 0B 00 02 09 CF

Reply: 7F 04 04 00 00 41 30 55 C7

The data part 0x 00 00 41 30 is converted to floating point data, that is, 11.00 m.

Example 2:

Request: 7F 04 0A 0B 00 02 09 CF

Re: 7F 04 04 FC FC FC FC D4 A2

In the data part, 0x FC FC FC FC is an error code, indicating that the mounting height is not set (the level cannot be calculated).

7.2.2 Query measurement results - air height

Request command:

Reply data:

Data definition: The default data type is float(little16) data, the default unit is meters (m), the data length is 4 bytes, and the lowest 16 bits are in the first.

Error code:

① When the measurement results exceed the range, output 0xFF FF FF FF;

② When the sensor is in the blind area, output 0xFE FE FE FE;

③ When the sensor echo energy is insufficient, the output 0xFD FD FD FD FD;

Example 1:

Request: 7F 04 0A 0F 00 02 48 0E

Reply: 7F 04 04 31 13 40 10 AA B6

The data part 0x 31 13 40 10 is converted to floating point data, that is, 2.253 m.

Example 2:

Request: 7F 04 0A 0F 00 02 48 0E

Reply: 7F 04 04 FE FE FE F4 7B

The data part 0x FE FE FE FE is the error code, indicating that the sensor is in the blind area and no valid data can be read.

7.3 Query configuration information instruction: Function Code 0x03

7.3.1 Broadcast query slave address

Request command:

Reply data:

Data definition: The data type is int16 data, and the data length is 2 Bytes.

Examples:

Request: FF 03 20 01 00 01 CB D4

Reply: 7F 03 02 00 7F D1 AE

The data part 0x 00 7F is converted to integer data, which is 127 or 0x7F.

7.3.2 Query the baud rate of the communication interface

Note: Baud rate only supports: 4800,9600,19200,38400,115200

Request command:

Reply data:

Data definition: The data type is int32(big) data, and the data length is 4 bytes.

Examples:

Request: 7F 03 20 02 00 02 64 15

Reply: 7F 03 04 00 00 25 80 7F 04

The data part 0x 00 00 25 80 is converted to integer data, which is 9600.

7.3.3 Query version information

Request command:

Reply data:

Data definition: The data type is int32 data, and the data length is 4 bytes. Version numbers were coded in BCD format.

Examples:

Request: 7F 03 20 04 00 02 84 14

Reply: 7F 03 04 20 23 09 08 99 A8

The data part is 0x 20230908, and the data is encoded in BCD format, namely the version number is 20230908.

7.3.4 Query calibration parameters

Request command:

Reply data:

Data definition: The data type is int16 data, the unit is millimeter (mm), and the data length is 2 Bytess.

Examples:

Request: 7F 03 20 52 00 01 24 05

Reply: 7F 03 02 00 10 91 82

The data part 0x 00 10 is converted to integer data, that is, 16 mm.

7.3.5 Query automatic push cycle

Note: When the automatic push period is >=300ms, the sensor will automatically push data. When the installation height is not set ( level cannot be calculated), push the air height data; When the mounting height is set, push the level data.

Request command:

Reply data:

Data definition: The data type is int16 data, the unit is milliseconds (ms), and the data length is 2 Bytes.

Examples:

Request: 7F 03 20 53 00 01 75 C5

Reply: 7F 03 02 03 E8 90 F0

Where the data part 0x 03 E8 is converted to integer data, that is, 1000 ms.

7.3.6 Query blind area

Request command:

Reply data:

Data definition: The default data type is float(little16) data, the default unit is meters (m), and the data length is 4 bytes.

Examples:

Request: 7F 03 20 44 00 02 85 C0

Reply: 7F 03 04 6D B7 3E AB

The data part 0x 6D B7 3E AB was converted to floating-point type data, that is, 0.334 m.

7.3.7 Query range

Request command:

Reply data:

Data definition: The default data type is float(little16) data, the default unit is meters (m), and the data length is 4 bytes.

Examples:

Request: 7F 03 20 46 00 02 24 00

Reply: 7F 03 04 00 00 42 20 55 4C

The data part 0x 00 00 42 20 is converted to floating point data, that is, 40.0m.

7.3.8 Check the depth at installation

Note: The water depth at the time of installation is used to calculate the installation height. Installation height = water depth at installation + real time height at installation. When setting the water depth at the time of installation, the installation height is automatically calculated and saved to the configuration.

Request command:

Reply data:

Data definition: The default data type is float(little16) data, the default unit is meters (m), and the data length is 4 bytes.

Examples:

Request: 7F 03 20 48 00 02 45 C3

Reply: 7F 03 04 47 AE 40 B1 E0 D5

The data part 0x 47 AE 40 B1 was converted to floating point data, that is, 5.54 m.

7.3.9 Check installation height

Note: Set the mounting height, which is used to calculate the level. Real-time level = installation height - real time height. At the same time, installation height = water depth at installation + height at installation time. Therefore, when setting the installation height, the water depth during installation will be automatically calculated and saved to the configuration.

Request command:

Reply data:

Data definition: The default data type is float(little16) data, the default unit is meters (m), and the data length is 4 bytes.

Examples:

Request: 7F 03 20 4A 00 02 E4 03

Reply: 7F 03 04 8A 64 41 2A BE 7C

The data part 0x 8A 64 41 2A is converted to floating point data, that is, 10.65m.

7.4 Set instruction: Function Code 0x10

7.4.1 Set the slave address

Request command:

Reply data:

Data definition: The data type is int16 data, and the data length is 2 Bytess.

Examples:

Request: 7F 10 20 01 00 01 02 00 01 6E 21

The data part 0x 00 01 is converted to integer data, that is, 1 or 0x01.

Reply: 7F 10 20 01 00 01 51 D7

7.4.2 Set baud rate of communication interface

Note: Baud rate only supports: 4800,9600,19200,38400,115200

Request command:

Reply data:

Data definition: The data type is int32 data, and the data length is 4 bytes.

Examples:

Request: 7F 10 20 02 00 02 04 00 01 C2 00 75 3E

The data part 0x 00 01 C2 00 is converted to integer data, which is 115200.

Reply: 7F 10 20 02 00 02 E1 D6

7.4.3 Setting calibration parameters

Request command:

Reply data:

Data definition: The data type is int16 data, the unit is millimeter (mm), and the data length is 2 Bytes.

Examples:

Request: 7F 10 20 52 00 01 02 00 10 A2 4E

The data part 0x 00 10 is converted to integer data, that is, 16 mm.

Reply: 7F 10 20 52 00 01 A1 C6

7.4.4 Set automatic push cycle

Note: When the automatic push period is >=300ms, the sensor will automatically push data. When the installation height is not set ( level cannot be calculated), push the air height data; When the mounting height is set, push the level data.

Request command:

Reply data:

Data definition: The data type is int16 data, the unit is milliseconds (ms), and the data length is 2 Bytes.

Examples:

Request: 7F 10 20 53 00 01 02 03 E8 A2 ED

Where the data part 0x 03 E8 is converted to integer data, that is, 1000 ms.

Reply: 7F 10 20 53 00 01 F0 06

7.4.5 Set the water depth at the time of installation

Note: The water depth at the time of installation is used to calculate the installation height. Installation height = water depth at installation + real time height at installation. When setting the water depth at the time of installation, the installation height is automatically calculated and saved to the configuration.

Request command:

Reply data:

Data definition: The default data type is float(little16) data, the default unit is meters (m), and the data length is 4 bytes.

Examples:

Request: 7F 10 20 48 00 02 04 47 AE 40 B1 75 30

The data part 0x 47 AE 40 B1 was converted to floating point data, that is, 5.54 m.

Reply: 7F 10 20 48 00 02 C0 00

7.4.6 Set the installation height

Note: The installation height is the distance from the sensor to the 0 object level. If the current water depth is 2 meters and the air height is 4 meters, the installation height is 6 meters. Set the mounting height, which is used to calculate the level. Real-time level = installation height - real time height. At the same time, installation height = water depth at installation + height at installation time. Therefore, when setting the installation height, the water depth during installation will be automatically calculated and saved to the configuration.

Request command:

Reply data:

Data definition: The default data type is float(little16) data, the default unit is meters (m), and the data length is 4 bytes.

Note: Setting the mounting height to 0 will clear the mounting height/water depth configuration at installation.

Examples:

Request: 7F 10 20 4A 00 02 04 8A 64 41 2A AA 40

The data part 0x 8A 64 41 2A is converted to floating point data, that is, 10.65m.

Reply: 7F 10 20 4A 00 02 61 C0

7.5 Text protocol

7.5.1 Communication protocol hardware interface parameters

The water level meter adopts serial communication, and the default parameters are as follows:

The timeout time was 50ms for each frame interval.

7.5.2 Description of communication protocol commands

Note: "n" represents a newline, corresponding to the hexadecimal number 0x0A. After the setup command configuration is successful, the configuration will be saved in Flash, and no reconfiguration is needed to restart the power outage.

The command error response is as follows:

1.Read the real spatio-temporal height

Unit: Meter (m)

2.Read the real-time level

Unit: Meter (m)

The calculation method of the level is: installation height - air height

3.Water depth at installation

Unit: Meter (m)

Note: The water depth at the time of installation is used to calculate the installation height. Installation height = water depth at installation + real time height at installation. When setting the water depth at the time of installation, the installation height is automatically calculated and saved to the configuration.

Read the water depth at installation:

Set the water depth at the time of installation:

4.Height of installation

Unit: Meter (m)

Note: Set the mounting height, which is used to calculate the level. Real-time level = installation height - real time height. At the same time, installation height = water depth at installation + height at installation time. Therefore, when setting the installation height, the water depth during installation will be automatically calculated and saved to the configuration.

Read mounting height:

Set mounting height:

Note: Setting the mounting height to 0 will clear the configuration for mounting height and water depth at installation.

5.Read the version number

6.Read range

Unit: Meter (m)

7.Read blind area

Unit: Meter (m)

8.Software reset (reboot)

9.Factory data reset

10.Frequency of acquisition

Unit: milliseconds (ms)

Note: The default acquisition frequency is 300ms, and the acquisition frequency can only be adjusted to 200ms at the earliest. (If the acquisition frequency jumps too fast, the speed of responding to the reply instructions will be slow, and the sending instructions may be incomplete, resulting in no response. In this case, the instruction can be sent again.)

Read acquisition frequency:

Set collection frequency:

11.Baud rate

Read baud rate:

Set baud rate

12.Calibration parameters

Unit: Millimeter (mm)

Real spatio-temporal height = sampling value -calibration parameter. Therefore, when the real space-time height is larger than a fixed value, it can be calibrated by adjusting the quasi-parameters.

Read calibration parameters:

Setting calibration parameters:

13.Automatic push cycle

Unit: milliseconds (ms)

Note: When the automatic push period is >=300ms, the sensor will automatically report the real-time data. Among them, when the installation height (or water depth during installation) is set, the real-time data reported automatically is the real-time level; If the installation height is not set (or the water depth during installation), the real-time data reported automatically is the real time height.

Read the automatic push cycle:

Set the automatic push cycle:

Xi'an Kacise Optronics Co.,Ltd. is a professional manufacturer of  measuring instruments , located in China xi’an City. Since 2008, Xi'an Kacise focused on the development and production of pressure, level and flow measuring instruments .

We have been specializing in manufacturing pressure, level and flow measuring instruments and related products for 10 years. Based on experienced technical and management personnel, through efforts of our entire staff, we have become a professional measuring instrument manufacturer and solution provider. And we are continuously trying to improve product quality.

Xi'an Kacise is qualified with ISO 9001-2008, GJB 9001B-2009, CE, intrinsic safety explosion-proof and isolated safety explosion-proof certificates, etc. which ensure that our products comply with international standards.

Kacise sensors have already been exported to America, Spain, Australia, Chile and 20 other countries and regions, and received many favorable feedbacks. Our overseas distributers are also increasing. We regard “reasonable prices, efficient production time and good after-sales service” as our tenet, and hope to cooperate with more customers for mutual development.

Our goal is simple: to sell the best products at the best prices, and provides industry-leading customer service. We personally get to know each of our customers, and we know how to discover the most valuable part of our business , to help others achieve their goals.