In the process of industrial automation, accurate measurement of the flow rate of conductive liquids is crucial for many industries. For example, in the chemical industry, precise flow control is related to the progress of chemical reactions and product quality; in the cooling system of the steel industry, errors in flow monitoring can cause equipment overheating and damage; in the municipal water supply and drainage field, flow measurement errors affect water resource management and cost accounting; in agricultural irrigation, inaccurate flow data can lead to water waste or insufficient crop irrigation.

Electromagnetic flowmeters, which work based on Faraday's law of electromagnetic induction, occupy an important position in the field of flow measurement. Currently, with the continuous progress of microelectronics technology, they show a significant trend of digitization and intelligence, and the measurement accuracy and stability are constantly improving. Digital signal processors (DSPs) are widely used to process sensor signals in real-time, effectively enhancing the anti-interference ability and improving the measurement accuracy. For example, in the industrial automation scenario, accurate flow measurement is crucial for production process control, and the technological progress of electromagnetic flowmeters provides strong support for it.

Analysis of Challenges Faced

Medium Complexity Challenge: In the petrochemical industry, fluid media are diverse and have complex properties, putting high demands on the measurement performance of electromagnetic flowmeters. Different media have different characteristics such as conductivity, corrosiveness, and viscosity. Traditional flowmeters have difficulty adapting, easily leading to problems such as large measurement errors and short equipment life.

Environmental Factor Interference: Changes in environmental conditions such as temperature and pressure significantly affect the measurement accuracy of electromagnetic flowmeters. In industrial production sites, the temperature fluctuates greatly. For example, a high-temperature environment may cause the sensor performance to drift, affecting the measurement accuracy; pressure changes will also interfere with the flow measurement, so accurate temperature and pressure compensation functions are required to ensure the stability of the measurement accuracy.

Anticorrosion and Anti-blocking Problems: The fluid media in industries such as chemical engineering are highly corrosive and prone to blockage, requiring high anticorrosion and anti-blocking performance of electromagnetic flowmeters. Corrosion will damage sensors and pipelines, shortening the service life of equipment; blockage will affect the normal flow of fluids, leading to measurement failure, increasing maintenance costs and downtime.

Low Flow Rate and Water-air Influence: In the network terminals or under specific working conditions, a too-low water flow rate affects the measurement accuracy; the presence of water and air in the pipeline will interfere with the measurement signal, distorting the measurement results and affecting the reliability of the flow data, posing a serious threat to the measurement accuracy.

Corebai Solution

· Amplifier: Used to amplify the weak signal output by the sensor. Since the amplitude of the signal output by the sensor is usually very small, it needs to be amplified by the amplifier to a range suitable for ADC input.

· ADC (Analog-to-Digital Converter): The ADC converts the analog signal into a digital signal for further digital processing and analysis.

· DAC (Digital-to-Analog Converter): The DAC can be used in an electromagnetic flowmeter to convert a digital control signal into an analog signal.

· RS485/RS422 Chip: Used for data transmission in the system. In an electromagnetic flowmeter, the RS485 chip can be used to transmit the flow data to a remote monitoring center or a control system.

· LDO (Low Dropout Linear Regulator): The LDO is used to provide a stable power supply for the electronic components in the electromagnetic flowmeter.

Block Diagram of Electromagnetic Flowmeter Application

I. ADC for Precise Analog-to-Digital Conversion (CBM79AD60G)

· High Resolution and Sampling Rate: The CBM79AD60G has a resolution as high as 18 bits, which means it can provide extremely high analog signal conversion accuracy. The sampling rate of this device is 5MSPS (5 million samples per second), enabling it to respond quickly to changes in the input signal, suitable for scenarios of high-speed data acquisition and real-time signal processing.

· Low Power Consumption: The CBM79AD60G adopts a low-power design with a total power consumption of only 64.5mW, which is especially important for portable devices and battery-powered applications.

· Built-in Conversion Clock Generation Circuit: The internal integration of the conversion clock generation circuit reduces the need for external components, simplifies the system design, and reduces the cost and complexity.

· Universal Serial Interface: All conversion results are output through a serial high-speed LVDS interface, suitable for a variety of communication protocols and data transmission requirements.

· High Signal-to-Noise Ratio: The signal-to-noise ratio (SNR) reaches 99dB, ensuring high-fidelity signal processing.

II. DAC for Diverse Digital-to-Analog Conversion (CBM53D24, CBM128S085)

· CBM53D24:

· Low Power Consumption: The low power consumption of the CBM53D24 under 3V power supply makes it very suitable for battery-powered or low-power applications.

· High Resolution: The 12-bit resolution provides accurate analog output, suitable for applications requiring high precision.

· Multi-channel Output: The 4-channel buffered voltage output enables it to control multiple analog signals simultaneously, increasing the flexibility of the application.

· Wide Voltage Range: The supply voltage range from 2.5V to 5.5V enables it to adapt to different power supply conditions.

· Compatibility: The 3-wire serial interface is compatible with multiple communication protocols such as SPI, QSPI, MICROWIRE, and DSP, facilitating connection with various microcontrollers and processors.

· CBM128S085:

· Multi-channel Output: The CBM128S085 provides 8 voltage analog output channels, which can meet the needs for multiple analog signals in various application scenarios.

· High Precision and Low Noise: The CBM128S085 performs excellently in terms of precision and noise control, which is crucial for applications requiring high-precision analog output.

· External Reference Voltage Input: This DAC supports external reference voltage input, and users can adjust the reference voltage according to specific requirements to obtain the desired analog output range and precision.

· Flexible Interface Configuration: The CBM128S085 supports SPI interface for data transmission, making its connection with digital devices such as microcontrollers simple and efficient.

· Wide Application Fields: Due to its multi-channel, high-precision, and low-noise characteristics, the CBM128S085 is suitable for multiple fields such as audio processing, data acquisition, and industrial control.

III. Powerful Amplifiers (CBM8629, CBM8605)

· CBM8629: CBM8629 is an amplifier with the following characteristic parameter advantages:

· Low Offset Voltage: The offset voltage of CBM8629 is only 1μV, which means that when there is no signal input, the voltage offset at the output end is very small, thus improving the measurement accuracy.

· Rail-to-rail Input and Output: CBM8629 supports rail-to-rail input and output swings, enabling it to maintain high efficiency and accuracy when processing various signal amplitudes.

· High Common-mode Rejection Ratio and Power Supply Rejection Ratio: Both CMRR and PSRR reach 130dB, helping to reduce the influence of common-mode signals and power supply noise on the amplifier output.

· CBM8605: CBM8605 is an amplifier with the following characteristic parameter advantages:

· Low Offset Voltage: CBM8605 has an extremely low input offset voltage, making it perform well in precision circuit applications and capable of accurately amplifying weak signals without distortion.

· Low Input Bias Current: Its input bias current is extremely low (with a maximum value of 5pA), which helps to reduce the error introduced when amplifying high-impedance source signals and improve the measurement accuracy.

· Low Noise: The noise level of CBM8605 is very low (with a typical value of 12nV/√Hz), which is crucial for applications requiring a high signal-to-noise ratio such as audio processing and sensor signal amplification.

· Wide Bandwidth: This amplifier has a gain-bandwidth product as high as 8.2MHz, meaning it can maintain high gain and low distortion characteristics in a wide frequency range, suitable for audio and other AC applications.

· Rail-to-rail Input/Output: The input/output can support rail-to-rail, greatly expanding the application range of this series of operational amplifiers and making signal processing more flexible.

· Diverse Packaging: CBM8605 usually has multiple packaging forms to choose from, such as WLCSP packaging, facilitating integration into different circuits.

IV. Stable Power Management (CBM1117)

· High Output Current: The CBM1117 can provide an output current as high as 0.8A, suitable for applications requiring a large current.

· Wide Input Voltage Range: It supports a wide input voltage range from 2.6V to 15V, suitable for various power supply conditions.

· Thermal Overload Protection and Current Limiting Function: When the chip temperature reaches approximately 160°C, the thermal shutdown circuit will disable the output to protect the device from overheating damage. The built-in current limiting circuit can limit the current when the output or adjustment terminal is short-circuited to prevent device damage.

V. Reliable Interface Transceiver (CBM3085)

· Low Power Consumption Design: The CBM3085 adopts a low-power design, very suitable for application scenarios requiring energy conservation.

· Data Transmission Rate: The data rate of this chip can reach 500kbps, meeting most data transmission requirements.

· High Stability: The CBM3085 can maintain the stability of the output voltage when the input voltage or load current changes, which is crucial for electronic devices requiring precise voltage control.

· ESD Protection: This chip provides ESD protection as high as 2000V (TTL/CMOS level) and 15000V (RS-485 level), ensuring normal operation in harsh environments.

· Operating Temperature Range: The operating temperature range of the CBM3085 is from -40°C to +125°C, enabling it to maintain stable performance in various extreme environments.

Application Case Analysis

I. Application in the Petrochemical Industry

· Precise Flow Control and Quality Improvement: In the crude oil processing process of a large petrochemical enterprise, the high resolution and sampling rate of the CBM79AD60G analog-to-digital converter accurately measure the crude oil flow rate, providing data support for precise control of the production process. The low noise characteristic of the CBM8605 amplifier ensures the accurate amplification of weak signals, improving the measurement accuracy. Precise flow control optimizes the ratio of crude oil and additives, improves the stability of product quality, reduces waste products, and lowers production costs.

· Equipment Safe Operation Guarantee: In petrochemical production, many pipelines transport corrosive media. The electromagnetic flowmeter uses the CBM53D24 digital-to-analog converter to control the operating parameters of anticorrosion equipment, ensuring the stable operation of the equipment in harsh environments. The CBM1117 power management chip provides a stable power supply, ensuring the normal operation of the flowmeter and related equipment under complex working conditions. Real-time flow monitoring can timely detect abnormal situations such as pipeline leakage or blockage, avoiding safety accidents and reducing production losses.

II. Application in the Water Treatment Field

· Optimization of the Water Supply System and Energy Saving and Consumption Reduction: In the urban water supply system, the multi-channel output characteristic of the CBM128S085 digital-to-analog converter is used to control the opening degrees of multiple valves and accurately adjust the water supply flow according to the water demand in different areas. The CBM3085 interface transceiver reliably transmits the flow data to the water supply dispatching center, realizing remote monitoring and intelligent control. By optimizing the distribution of the water supply flow, the pressure loss of the pipe network is reduced, the water supply efficiency is improved, energy is saved, and the operation cost is reduced.

· Precise Monitoring in the Sewage Treatment Process: In a sewage treatment plant, the electromagnetic flowmeter accurately measures the sewage flow rate and water quality parameters (such as pH and dissolved oxygen). The CBM8629 amplifier amplifies the sensor signal with high precision, and the CBM79AD60G analog-to-digital converter converts the analog signal into a digital signal and then sends it to the control system for processing. The real-time monitoring data provides a basis for the adjustment of the sewage treatment process, ensuring that the sewage treatment meets the discharge standards and protecting the environment.

III. Application in the Food Manufacturing Industry

· Production Process Automation and Quality Control: On the food and beverage production line, the CBM3085 communication interface transmits the flow data to the production control system in real-time, realizing automated production control. The CBM8605 amplifier ensures the accuracy of flow measurement, accurately controls the amount of raw materials added and the product packaging amount, ensures the consistency of product quality, and improves production efficiency.

· Compliance with Hygiene Standards and Equipment Reliability: The food industry has high requirements for equipment hygiene. The electromagnetic flowmeter adopts corrosion-resistant materials and hygienic design to meet the hygiene standards. The CBM1117 power management chip provides a stable power supply, ensuring the long-term stable operation of the equipment, reducing equipment failures and downtime, and ensuring the continuity and safety of food production.