Analysis of the Working Principle and Function of Signal Isolator with Gate Opening
Working principle: Firstly, the signal of the transmitter or instrument needs to be modulated and transformed through semiconductor devices, then isolated and transformed through optical or magnetic sensing devices, and finally demodulated and transformed back to the original signal before isolation. At the same time, the power supply of the isolated signal is isolated and processed. Ensure independence between the transformed signal, power supply, and ground.
Function:
1. Protect the lower level control circuit.
2. Weaken the impact of environmental noise on the testing circuit.
3. Suppress interference from public grounding, frequency converters, solenoid valves, and unknown pulses on equipment; At the same time, it has the function of limiting voltage and rated current for lower level equipment, which is the faithful protection of transmitters, instruments, frequency converters, solenoid valve PLC/DCS input and output, and communication interfaces. The DIN series rail structure is easy to install and can effectively isolate the potential between input, output, power supply, and ground. Capable of overcoming frequency converter noise and various high and low frequency pulsation interferences.
What are the main types of signal isolators?
Isolator: In industrial production, in order to increase the load capacity of instruments and ensure that instruments connected to the same signal do not interfere with each other, electrical safety performance has been improved. It is necessary to collect, amplify, calculate, and perform anti-interference processing on the input voltage, current, frequency, resistance, and other signals, and then output isolated current and voltage signals again for safe use in secondary instruments or PLC/DCS.
Distributor: Industrial sites generally require a two-wire transmission method, which provides 24V distribution power for primary instruments such as transmitters. At the same time, the input current signal needs to be collected, amplified, calculated, and anti-interference processed
Then output isolated current and voltage signals for use by subsequent secondary instruments or other instruments.
Safety barrier: Some very 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. At the same time, they also need to have safe spark explosion-proof performance, which can reliably restrain power supply power, prevent ignition between power supply, signal and ground, limit current and voltage, double limit signal and power circuit, and limit the energy entering dangerous places within a safe quota range.
What should be noted during the installation and maintenance of signal isolators?
Due to different manufacturers, the production process and wiring definitions for isolators are also different, but the usage scenarios are basically the same, so the protection requirements and maintenance for the products are basically the same.
Before use, it is necessary to read the instructions in detail.
When used for signal isolation, the input terminal should be connected in series to the loop circuit, and the output terminal should be connected to the sampling circuit.
When used as an isolated power distribution, the input terminal should be connected in series with the power circuit, and the output terminal should be connected to the transmitter.
If it is not working properly, you should first check whether the wiring is correct and pay attention to whether the power supply has polarity.
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