Tag: signal isolator

In the PLC/DCS control system on the industrial site, the measurement signal is often unstable. One is caused by electromagnetic interference, and the other is the infiltration of high-frequency signals. For example, the current signal output controls the inverter, and the high-frequency interference of the inverter infiltrates the signal. Among them, such interference signals make the frequency converter and valves work unstable. Installing a signal isolator between the signal connections of the two devices is one of the methods to solve the influence of electromagnetic interference and high-frequency signal penetration.

Thanks to the rapid development of technology nowadays, there are various kinds of isolation switches on the market, designed for different uses. They may be intended specifically for industrial applications or for home use. Choice of isolator switches depends on the requirement and application. We'll take a look at them one at a time and try to understand what's special about them. In this article, we will talk about types and applications of isolator.

The isolator uses a kind of linear optocoupler isolation principle, which converts the input signal and outputs it. Input, output and working power are isolated from each other, especially suitable for use with equipment and meters that require electrical isolation. Isolator, also known as signal isolators, is an important part of industrial control systems. 

Loop powered signal isolator is one type of signal isolator with a power supply module. The function of the loop powered signal isolator is to isolate the current source signal input to the loop powered isolator and output a DC signal that is isolated from and proportional to the input signal.
Loop powered signal isolators use the signal current in the input loop to power the meter (take out some energy of input signal inside the isolator to drive the isolator), without any external power supply.