High-precision 4-20mA adjustable constant current source signal output device and output method

Abstract

The invention relates to the technical field of 4-20mA constant current source signal output, and particularly discloses a high-precision 4-20mA adjustable constant current source signal output deviceand output method. The device comprises a control system, an input and output device, a voltage / current converter, a load assembly and a power supply device for supplying power, wherein the control system comprises an STM32 single-chip microcomputer and a D / A conversion module arranged in the STM32 single-chip microcomputer; the input and output device comprises a keyboard input device and a liquid crystal display; the load assembly comprises an electronic pressure regulating valve; and the voltage / current converter comprises a data processing module, a voltage follower circuit and a voltage-to-current module, the output end of the data processing module is connected with the voltage follower circuit, and the output end of the voltage follower circuit is connected with the voltage-to-current module. According to the device, 0-3.3V analog voltage signals are output through an IO port of the STM32 single-chip microcomputer, and the voltage / current conversion module is controlled to output 4-20mA current signals, so that the requirement of the current signals of a 4-20mA output interface is met according to the change of a given value.

Description

Technical field[0001]The invention relates to the technical field of 4-20mA constant current source signal output, in particular to a high-precision 4-20mA adjustable constant current source signal output device and output method.Background technique[0002]Various non-electrical physical quantities measured by transmitters in industrial applications, such as temperature, pressure, flow, humidity, etc., need to be transmitted to the central control room over a long distance, which needs to be converted into electrical signals that meet industrial transmission standards, such as 0 -5V, 0-20mA or 4-20mA. The current signal has strong anti-interference ability on the transmission line, and will not produce a voltage drop on the transmission line, which avoids the above-mentioned problems. Therefore, the 4-20mA current signal has become the mainstream signal transmission method in the industrial field.[0003]The existing 4-20mA current signal realization circuit often uses a V-I conversion...

AI Technical Summary

Problems solved by technology

It can be seen that the current output of most instruments is realized by relatively complex circuits. The more complex the circuit, the more electronic components are used, the greater the probability of failure, and the higher the cost of the product.

Therefore, this complex circuit can no longer adapt to product development and application

[0004] The hydrogenation machine will release a large amount of heat during the process of filling the vehicle with hydrogen. If the heat is not controlled, a large amount of heat will accumulate, which will easily cause the on-board gas storage tank to overheat and cause the hydrogen to detonate, which is very dangerous

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