How signal isolators work

working principle:

 

First, the signal of the transmitter or the instrument is modulated by the semiconductor device, and then is isolated and converted by the light-sensing or magnetic-inductance device, and then demodulated and converted back to the original signal before isolation, and at the same time, the power supply of the isolated signal is isolated. . Ensure absolute independence between transformed signals, power supply, and ground.

 

Features:

 

One: Protect the lower-level control loop.

 

Second: Weaken the impact of environmental noise on the test circuit.

 

Three: Suppress the interference of common ground, frequency converter, solenoid valve and unknown pulse to the equipment; meanwhile, it has the function of limiting pressure and flow for lower-level equipment. It is the transmitter, meter, frequency converter, solenoid valve PLC/DCS input and output, and communication. The loyal protection of the interface.

 

Standard series rail structure, easy to install, and effective isolation: input, output and potential between power supply and earth. Can overcome the inverter noise and various high and low frequency pulsation interference.

 

What are the main types of signal isolator?

 

1) Isolator:

 

In industrial production, to increase the load capacity of the instrument and ensure that the instruments connected to the same signal do not interfere with each other and improve the electrical safety performance. Need to input the voltage, current or frequency, resistance and other signals to collect, amplify, calculate, and anti-jamming processing, and then output the isolated current and voltage signals, safe to send to the secondary instrument or plc \ dcs use.

 

2) Distribution:

 

The industrial site generally needs to adopt the two-wire transmission method. It is necessary to provide 24V distribution power for a meter such as a transmitter. At the same time, the input current signal must be collected, amplified, calculated, and subjected to anti-jamming processing, and then output. Isolated current and voltage signals for use by subsequent secondary instruments or other instruments.

 

3) Safety barriers:

 

Some special industrial sites (such as gas companies and chemical plants) not only require two-wire transmission, but also provide power distribution and signal isolation functions. They also need to have the performance of safety spark explosion, reliably contain power, prevent power supply, Ignition between signal and ground, current limiting, and step-down double limit signal and power supply circuit limit the energy entering hazardous locations within the safe fixed range.