SKU: SENS-4086
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MaxBotix MB7851-B20 Ultrasonic Tank Level Sensor - RS232/TTL Serial & Analog Voltage Output

₹16,389.00 (Inclusive of all taxes)
Out of Stock

The MaxBotix MB7851-B20 is a high-performance ultrasonic tank level sensor designed for industrial liquid level monitoring. It features a 3/4″ NPT mounting thread, operates from 3V to 5.5V, and provides simultaneous RS232/TTL serial and analog voltage outputs for seamless integration with PLCs, data loggers, and microcontrollers like Arduino.

Features

  • High-performance ultrasonic sensor for precise liquid level detection from 50 mm to 5000 mm.
  • Simultaneous RS232/TTL serial (9600 baud) and scaled analog voltage outputs for flexible system integration.
  • Industrial-grade construction with 3/4″ NPT mounting thread and operation from –40°C to +65°C.
  • Advanced noise rejection algorithms and real-time auto-calibration for reliable readings in acoustically noisy environments.
  • Low power consumption with a 3V to 5.5V supply and an average current draw of 1.8 mA.

Out of stock

Description

The MaxBotix MB7851-B20 utilizes a 42 kHz ultrasonic transducer for non-contact liquid level sensing in tanks, barrels, and bins. Its narrow beam pattern and high acoustic power output ensure reliable detection even in containers with internal obstructions. The sensor incorporates real-time waveform signature analysis and automatic sensitivity adjustment to provide virtually noise-free distance readings.

Factory-calibrated for long-range detection zones, the MB7851-B20 offers a 1 mm resolution and a 1.95 Hz read rate. It features a unique “teaching” mode via serial communication, allowing it to learn the acoustic profile of an empty container, which enhances accuracy in complex environments. The sensor is designed for continuous free-run operation or triggered measurement on demand.

Key Features

  • Ultrasonic sensing with 42 kHz operating frequency for precise liquid level measurement.
  • Dual-output interface: RS232/TTL serial communication and analog voltage output scaled to (Vcc/1024) per cm.
  • Industrial temperature range from –40°C to +65°C for harsh environment operation.
  • Robust housing with 3/4" National Pipe Thread (NPT) straight connection for secure tank mounting.
  • Advanced signal processing with real-time background auto-calibration and noise rejection algorithms.
  • Low average current consumption (1.8 mA) enabling extended operation on 3V to 5.5V supplies.
  • 1 mm resolution and a maximum sensing range of 5 meters (500 cm).
  • Teaching feature via serial interface to adapt to specific container acoustics and obstructions.

Applications

  • Industrial tank and silo level monitoring for water, chemicals, or fuels.
  • Liquid inventory management in storage barrels and intermediate bulk containers (IBCs).
  • Process control and leak detection in manufacturing and wastewater treatment plants.
  • Agricultural irrigation system water level monitoring and control.
  • Marine bilge and ballast tank level sensing.

Technical Specifications

Model NumberMB7851-B20
Operating Voltage3V to 5.5V DC
Average Current Draw1.8 mA
Ultrasonic Frequency42 kHz
Read Rate1.95 Hz
Measurement Range50 mm to 5000 mm
Resolution1 mm
Output InterfacesRS232/TTL Serial (9600 baud, 8N1), Scaled Analog Voltage
Operating Temperature–40°C to +65°C
Mounting Thread3/4" National Pipe Thread (NPT) Straight
Horn Opening Thread2" NPT Straight
Outer Diameter58.8 mm
Length135 mm
Nut Size62.8 mm
Weight92 g

Frequently Asked Questions

What are the output options of the MB7851-B20 sensor and how do I interface with them?

The MB7851-B20 provides two simultaneous outputs. The RS232/TTL serial output communicates at 9600 baud (8N1) and provides direct digital range data, ideal for microcontrollers or PLCs. The analog voltage output provides a real-time voltage envelope and a scaled output where the voltage corresponds to distance at a scaling of (Vcc/1024) per centimeter, suitable for analog input modules.

What is the purpose of the sensor's 'teaching' feature and how is it activated?

The teaching feature allows the sensor to learn the acoustic signature of an empty container, compensating for internal obstructions like corrugations or baffles. This feature is only accessible via the serial communication interface. By sending specific serial commands, you can train the sensor to establish a baseline 'empty' reading, significantly improving measurement accuracy in complex tank geometries.

What are the mounting requirements and environmental specifications for this sensor?

The sensor body has a 3/4" NPT straight thread for mounting through a tank wall or lid. The ultrasonic horn itself has a 2" NPT thread. It is designed for industrial environments with an operating temperature range of –40°C to +65°C and features weather-resistant construction. Ensure the mounting surface is stable and the sensing path is clear of persistent foam or heavy turbulence for optimal performance.

Can this sensor operate continuously and what is its power consumption?

Yes, the sensor supports free-run mode for continuous measurement at a 1.95 Hz update rate. It has a very low average current draw of 1.8 mA when operating from its 3V to 5.5V DC supply, making it suitable for battery-powered or low-energy monitoring systems. It can also be placed in a triggered mode to take measurements on demand.

Package Includes

  • 1 x MaxBotix MB7851-B20 Ultrasonic Tank Level Sensor

Additional Information

Weight 0.092 kg