The main signal output mode of the transmitter is current output, and the current output range is commonly used in 0~20mA and 4~20mA. For the transmitter with an output of 0~20mA, we only need to select the appropriate step-down resistor in the circuit design, and directly convert the 0-5V or 0-10V voltage on the resistor into a digital signal at the input interface of the A/D converter, and the circuit debugging and data processing are relatively simple. However, the disadvantage is that it is impossible to distinguish the damage of the transmitter, and it is impossible to distinguish between the open circuit and the short circuit of the transmitter output. For transmitters with an output of 4~20mA, circuit debugging and data processing are cumbersome. However, this kind of transmitter can judge whether the circuit is faulty and whether the transmitter is damaged by detecting the current within the normal range when the transmitter line is not connected, short circuit or damaged, so it is more widely used. Because when the 4~20mA transmitter outputs 4mA, the voltage on the sampling resistance is not equal to 0, and the digital quantity directly converted by the analog-to-digital conversion circuit is not 0, the single-chip microcomputer cannot be directly used, and the calculation through the formula is too complicated. Therefore, the general method is to eliminate the voltage drop generated by the 4mA on the sampling resistor through a hardware circuit, and then perform an A/D conversion. There are many advantages to the current output of the transmitter, which we have already covered in previous articles. In the future, there will be even more transmitters that use current signal output. Only a deeper understanding of the relevant technical knowledge can help us to use the transmitter better. If you have any questions about product consultation, product customization, agency, technical inquiry, quotation, etc., please contact Xingyi, 400-600-4496!