1. Product introduction

The underwater obstacle avoidance sensor uses ultrasonic waves to transmit in the water. When it encounters the measured object,it reflects back,measures the distance between the sensor and the measured object,and transmits it to ships,buoys,underwater unmanned vehicles and other equipment. It can be used as a It is used for obstacle avoidance and can also be used for underwater obstacle avoidance.

The product protection level reaches IP68 level and be immersed in water for a time without being damaged.

2. Measurement principle

The ultrasonic waves emitted by the ultrasonic probe propagate through water,encounter the measured target,and then return to the ultrasonic probe through the water after reflection. Because the time of transmission and reception can be known,according to this time × speed of sound ÷ 2 = probe The distance between the emitting surface and the measured target.

Calculation formula: D = C*t/2

(Divided by 2 because the sound wave actually goes back and forth from emission to reception,D is the distance,C is the speed of sound,and t is the time).

If the time difference between transmitting and receiving is 0.01 seconds,the speed of sound in fresh water at room temperature is 1500 meters/second.

1500 meters/second × 0.01 second = 15 meters

15 meters÷2=7.50 meters

That is,the distance between the probe emission surface and the measured target is 7.50 meters.

3. Main technical indicators

3.1 Factory test standards:

Measuring water quality: clear water,turbidity<500NTU;

Liquidity: still water;

Water temperature: 20～30℃

Water depth:<1.00 meters

Tested target: a flat swimming pool wall with a certain roughness and an area of at least 1 meter × 1 meter.

3.2 Corresponding numbers of 8 beams

3.2.1 Downward is beam No. 1

3.2.2 Distribution of 7 beams in the horizontal direction

3.5 Technical parameters

Measurement output result: the distance value between the probe emission surface and the measured target;

Sensor connection method: 2 internal threads,connected to the underwater robot through an adapter

Wiring method: 4-core watertight aviation plug

Tips: For wiring,please check the identification plate on the line. Do not make the wrong connection.

Output instructions: yellow wire V+,blue wire V GND,red wire TTL +,black wire TTL-;

Blind area range:

400KHz: blind zone 0.30~0.40 meters,standard measurement range 5 meters;
500KHz: blind zone 0.20~0.25 meters,standard measurement range 3 meters;

Protection level: IP68

Working water depth: three types: within 100 meters,within 200 meters,and within 300 meters;
Power supply voltage range: DC 12.0V ~ 26.0V;

Supply voltage and current: DC 24V,current<60mA; DC 12V,current<120mA;

Device power consumption:

DC 24V power supply: minimum power 24V×60mA=1.44W;

DC 12V power supply: minimum power 12V×120mA=1.44W;

Output signal 1: 1 channel RS485 MODBUS protocol,

Communication method 1: Responsive type,the host computer sends an instruction,and the sensor replies with the current measurement data.

Communication method 2: Active upload,hexadecimal data,5-10 times per second.

Measurement speed: All 8 beams are measured at one time,and the time is 150ms~200mS.

Display: No display

Supporting cable length: 1 meter,up to 10 meters;

Cable outlet: 4 cores

Working water temperature: -10～+60℃;

3.6 Application scope

• Underwater position detection,distance detection

• Underwater robot obstacle avoidance and collision detection

• Fixed-distance use of underwater robots

• Underwater pipeline inner diameter measurement

• Underwater pipeline center walking control

4. Appearance and wiring

4.1 Product appearance

4.2 Wiring method

5. Precautions

6.1 Installation precautions

① Do not connect the power cord reversely,as it will cause the internal circuit to burn out;

② The power supply cannot be supplied incorrectly. If it is supplied incorrectly,the internal circuit will be burned if the voltage is higher than the maximum voltage that the instrument can withstand.

③TTL output wiring cannot be connected reversely,otherwise it will cause the output to be garbled or blank.

④Cables cannot be used to bear load or force.

⑤The ends of the cable outlet must be protected from water ingress or immersion,otherwise the equipment will be damaged.

⑥Cables must be protected from wear,cuts,corrosion,etc.,otherwise the equipment will be damaged.

Chapter 4 Communication Protocol

4.1 Protocol Description

4.1.1 Communication parameter setting

1. The hardware adopts TTL,master-slave half-duplex communication,the host calls the slave address,and the slave responds to the communication.

2. Data frame: 10 bits,1 start bit,8 data bits,1 stop bit,no checksum.

3. Default baud rate:

4.1.2 Read register value