Classification of RS485 Converters
Common 485 converters can be divided into the following categories in terms of performance: passive 485 converters, active 485 converters, optically isolated 485 converters, network 485 converters, and optical fiber to 485 converters.
1. Passive RS485 Converters
The passive 485 converter is the smallest in size. It uses serial port power stealing technology to supply power and does not require external power supply, so it is more flexible in application. Due to its small size, many protection circuits cannot be implemented, resulting in the protection of 485 devices and computers. Very good; due to the use of serial port stealing technology, the power supply is insufficient, resulting in a small load. The passive 485 converter claims to have the function of lightning protection. Due to its small size, it is not very realistic to add components such as lightning protection tubes in it. Even if there is, the performance is not very good. Passive 485 converters are mainly used in occasions where the requirements are not very high.
2. Active RS485 Converters
Active 485 converters are generally products with power supply, and components such as lightning protection tubes can prevent external damage such as surges, electromagnetic interference, and lightning interference. Protect computers and 485 devices. The active type 485 converter has a much stronger load capacity than the passive type, and the transmission distance is usually ≥1200 meters/9600bps.
3. Optically Isolated RS485 Converters
Optical isolation type 485 converters use external power supply. Among them, it is divided into single-ended isolation and double-ended isolation. Single-ended optical isolation means that the optical isolation chip and lightning protection technology are used on the 485 signal channel, so that the electrical signal is converted into an optical signal, and then the optical signal is converted into an electrical signal. signal, so that there is no electrical contact on the 485 signal channel, thus achieving isolation. The double-terminal isolation is based on the realization of photoelectric isolation on the 485 signal, and then the power supply of the 485 converter is powered, and a transformer is used between the 232 terminal and the 485 terminal, so that the power supply has no electrical contact, thus realizing the true sense. isolation. The company's AU-361, AU-338 and other models of photoelectric isolation type 485 converters belong to this category, providing complete protection such as lightning protection, double-end isolation, etc. to protect your computer and 485 equipment.
4. Network RS485 Converters
The network type 485 converter (serial port server) provides serial port to network function, which can convert RS-232/485/422 signal into TCP/IP network signal, and realize the data compatible with RS-232/485/422 and TCP/IP network Two-way transparent transmission, so that the serial device has the function of TCP/IP network interface, and data exchange can be carried out through the Internet, which greatly expands the communication distance of the serial device.
5. Optical Fiber to RS485 Converters
Optical fiber to 485 converter (also known as 485 optical cat) converts RS232, RS485/422 signals into optical signals, such products should be used in pairs, divided into (transmitting end) and (receiving end), using optical fiber to transmit RS232, RS485/ 422 signal bidirectional transparent transmission, 485-to-fiber converter has good anti-surge, electromagnetic interference and lightning interference, multi-mode optical cat can transmit within 2 kilometers, single-mode optical cat can transmit more than 10 kilometers; 485-to-fiber converter is mainly It is used in environments with strong confidentiality and complex electromagnetic interference.
