Shanghai Chenzhu Instrument CO., LTD.
Shanghai Chenzhu Instrument CO., LTD.

Working Principles of the Signal Isolator

Oct 28 , 2021

Ⅰ. Working principles of the signal isolator

Signal isolator generally refers to the signal isolato in light-current system, to protect the subordinate signal system from the influence and interference of the superior system. Signal isolator is a kind of signal isolation device, which transforms input single, double current or voltage signals to isolated single, double linear current or voltage signals, and improves the electrical isolation performance between input, output and power supply.

The signal isolator first modulates and transforms the signal received by the PLC through a semiconductor device, and then isolates and transforms it through a light-sensitive or magnetic-sensitive device, and then demodulates and transforms it back to the original signal or a different signal before isolation. At the same time, isolate the power supply of the isolated signal to ensure absolute independence between the transformed signal, power supply, and ground. The signal will encounter various interferences during transmission. To ensure the stability of the signal, the use of a signal isolator is particularly important.


Ⅱ. Functions of the signal isolator

As for signal isolator function, it can protect subordinate control loop. Signal isolator can reduce the influence of ambient noise on the test circuit. Signal isolator suppresses the interference of public grounding, convertor, electron magnetic valve and unknown pulse to the equipment. At the same time, signal isolator has the function of voltage limiting, choke flow to the subordinate equipment, which is the faithful protection of transmitter, instrument, transducer, electron magnetic valve PLC/DCS input and output and communication interface. The DIN series rail structure of the signal isolator is easy to install and can effectively isolate the potential between the input, output, power supply and the ground. The signal isolator can overcome the frequency converter noise and various high and low frequency pulsation interference.