What are the functions of DC signal isolators

The function of DC signal isolator:

(1) Ground circulation interference

In the whole process of industrial production to complete the monitoring and manipulation must use a variety of instruments, automatic control systems and electric actuators, the signal transmission in the middle of them not only has very weak to millivolt level, mAh level of small signals; There are tens of volts, thousands of volts, hundreds of amperes of large signals; Not only low frequency direct current signals, but also high frequency pulse signals, the composition of the system software is usually found in the instrument panel and equipment in the middle of the transmission interference with each other, resulting in system software instability and even operational errors, the occurrence of such a situation in addition to each instrument and equipment, equipment's own characteristics such as anti-electromagnetic interference hazards, Another very key reason is that all kinds of instruments and equipment must be grounded according to regulations and objectives, and the shell must be grounded to the ground; In order to better make the power supply circuit work normally, the system must have a public anchor point; In order to better suppress the interference and shield, the shield must also be grounded, but because there is a potential difference between the positioning point in the middle of the instrument panel and the device (that is, the common address of each device is not the same), the problem of "ground electric field" and "grounding device electric field" is a problem that must be dealt with in the whole process of system software to solve the signal.

(2) Of course interference

Lightning is a key natural source of interference, and the interference caused by lightning can be transmitted to areas thousands of kilometers away. The frequency domain mode of lightning interference is a large pulse accumulated on a series of arbitrary pulse cases. Cosmic noise is caused by electromagnetic radiation, which changes continuously throughout the day. Solar noise is accompanied by strong changes in solar activity. Natural noise is critical to communication interference, and lightning energy spike pulse can cause damage to many equipment, should prevent or reduce the level of damage, reduce losses.

(3) Interference by human factors

The direct cause of electromagnetic interference is the change of working voltage or current in the electrical conductor, that is, a large dv/dt or di/dt.dv/dt or di/dt can cause ionizing radiation in the electrical conductor. On the one hand, we can use this characteristic to accomplish special functions, such as endless communication, radar detection or other functions, on the other hand, electronic devices in the operation of the device, because the dv/dt or di/dt in the electrical conductor will cause radiation with the electromagnetic wave. Regardless of the subjective purpose, the objective induction of the natural environment by electromagnetic leads to environmental pollution. There are also processing companies in the processing process will often have some large and medium-sized equipment (motor, soft starter) often power switch, they will also lead to some soluble, rational interference, will also harm the instrument equipment all normal display information or collection. Where there is a sudden change in current and voltage, there is no doubt that electromagnetic interference will occur. Data pulse power supply circuit is a typical source of interference, with the extensive use of electronic information technology, electromagnetic radiation will become more and more serious.