Brief Introduction to Data Collector
Data acquisition technology has strong practicability in industry, aerospace, military, etc. With the development of modern technology, data acquisition technology has been widely used and developed in many fields. At the same time, higher requirements are put forward for the accuracy, anti-interference ability, safety and communication compatibility of the data collector. Based on the above requirements, a design scheme of a data collector based on STM32F101 is proposed. The data collector uses MODBUS protocol as the RS485 communication standard protocol. The signal conditioning circuit and the AD sampling channel of STM32F101 are all protected by hardware isolation and can be sampled at the same time. 3 channels of DC0-5V voltage signals, 3 channels of DC4-20mA current signals and 6 channels of switch input signals. Experiments have proved that this data collector has high measurement accuracy and meets the needs of industrial field applications.
Signal acquisition mainly includes voltage signal, current signal, frequency signal and switch signal. With the development of modern technology, the sensor mainly outputs standard voltage and current signals, and the sensor converts external non-electricity signals into standard electrical signals for output , The data collector designed in this subject can collect voltage, current, and switch input and output signals at the same time, and each part works independently. The hardware conditioning circuit adopts signal isolation technology, and the data collector uses RS485 communication with the host computer. The MODBUS protocol is used as a communication protocol to facilitate data sharing between data collectors and other industrial equipment.
The data collector uses the cost-effective STM32F101 as the core processor, and the processing speed after clock multiplication can reach 36MHz; the internal 12-bit AD conversion channel ensures the speed and accuracy of data sampling and processing.
The working principle of data collector
The data collector has a standard voltage, current and switch input signal sampling interface. The analog signal sampling interface circuit uses HCNR201 linear optocoupler for signal isolation. The voltage signal interface can input DC0-5V signal, the input voltage signal is filtered, isolated and limited by the voltage signal conditioning circuit, and then sent to the AD sampling channel of STM32F101; the current signal interface can input 4-20mA signal, the input current The signal is converted into a voltage signal through a precision sampling resistor, and then the converted voltage signal is sent to the voltage signal conditioning circuit for processing, and finally sent to the AD sampling channel; the switch input interface is isolated by an optocoupler to realize photoelectric conversion And isolation protection. STM32F101 software processes the sampled data, and then uploads the data to the host computer or other equipment through the RS485 communication interface to complete the data collection, processing and communication functions.