How does Optical Isolation achieve signal transmission in Serial Port Converter?
Publish Time: 2024-11-11
In Serial Port Converter, Optical Isolation is a key technology used to ensure the security and stability of signal transmission.
1. Basic composition
Optical Isolation mainly consists of light-emitting elements (usually light-emitting diodes LED) and photosensitive elements (such as phototransistors or photosensitive diodes in optocouplers). In the Serial Port Converter, these two elements are isolated from each other. They are encapsulated in an independent structure, but are optically interrelated.
2. Electrical-optical conversion process
When the input electrical signal of the serial port enters the Optical Isolation part, it first reaches the light-emitting diode. Depending on the level of the input signal, the light-emitting diode will have different working states. If it is a high-level signal, the light-emitting diode will turn on and emit light; if it is a low-level signal, the light-emitting diode will not emit light. This process realizes the conversion of electrical signals to optical signals. For example, in the signal transmission of the RS-232 serial port standard, the 0 and 1 level changes of the data bit will control the light-emitting diode accordingly.
3. Light-to-Electricity Conversion Process
The emitted light will shine on the photosensitive element. When light shines on a phototransistor or photodiode, it will cause a photoelectric effect inside it. For a phototransistor, light will cause it to generate a base current, thereby causing the collector-emitter to conduct and generate a corresponding electrical signal; for a photodiode, light will generate a photocurrent. In this way, the light signal is converted back into an electrical signal. After proper amplification and processing, this newly generated electrical signal can continue to be transmitted in the subsequent circuits of the Serial Port Converter.
4. Isolation Effect
Since the light-emitting element and the photosensitive element transmit information through light, they are completely isolated electrically. This means that even if there is electrical interference, voltage fluctuations or even short circuits on the serial port input side, these problems will not directly affect the circuits and devices on the output side. This isolation effectively protects the devices connected to the output end of the Serial Port Converter, such as computers, industrial controllers, etc., avoiding damage caused by electrical problems on the serial port input side, while also reducing the impact of interference signals on the transmitted data, ensuring the accuracy and reliability of data during conversion and transmission.
