The Working Principle and Function of Signal Isolators

Signal Isolators, also known as isolators, are network devices that convert input signals for output using the principle of linear optical coupling isolation. They are important components in industrial control systems and are often used with equipment and instruments that require electrical isolation.

What is the Role of Signal Isolators?

Signal isolators are often used in various industrial productions, especially in electronics and communications companies, where they are indispensable. The main functions of using signal isolators include:

Isolating Input and Output Signals

After using signal isolators, on one hand, they can effectively solve mutual interference between loops and equipment, and on the other hand, they can also effectively eliminate some external electromagnetic interference during signal transmission.

Avoiding Power Conflicts

Mechanical equipment needs to work in environments with power sources. When there are many power sources, conflicts may occur, affecting the normal operation of the equipment. Using signal isolators can effectively resolve this issue.

Isolating and distributing signals for some equipment

Many pieces of equipment carry loads that require the use of resistors and wires. Generally, the length of the wires will affect the resistance of the equipment. Changes in resistance can affect the voltage of the entire equipment. Using signal isolators can isolate and distribute signals to solve these issues.

Protecting lower-level control circuits

Lower-level control circuits are complex, and slight missteps can affect the entire circuit. Signal isolators can control the entire loop, protecting the lower-level control circuits.

Reducing the impact of external noise on test circuits

Signal isolators have a certain role in reducing noise, minimizing the impact of noise on test circuits.

Controlling Common Grounding and Interference from Variable Frequency Devices on Equipment

Using variable frequency devices can bring higher efficiency but also cause some negative impacts on equipment. Signal isolators can isolate these interferences.

Signal Isolator Working Principle

Various instruments and devices are used in industrial production. The signals generated by these instruments can interfere with each other. To prevent signal distortion during transmission, signal isolators are used. So, what is the signal isolator working principle?

Signal isolators primarily use the principle of linear optical coupling isolation. Linear optical coupling is a type of optocoupler used for analog signal isolation. It has two optical receiving circuits that can cancel out the non-linearity of the direct path through the non-linearity of the feedback path, achieving linear isolation, isolating current, and reducing environmental interference on test circuits.

In actual operation, signal isolators first modulate and transform the signal from the transmitter or instrument using semiconductor devices, then isolate and convert it using optical or magnetic sensing devices. Afterward, they demodulate and transform the signal back to its original state before isolation, isolating the power supply for the isolated signal. This ensures the converted signal, power supply, and ground are absolutely independent, without any other interference.