485 is a remote weighing data acquisition method for communication interfaces. When the communication distance is required to be tens of meters to thousands of meters, RS-485 serial bus standard is widely used. RS-485 uses balanced transmission and differential reception, so it has the ability to suppress common-mode interference.
Widely used in industrial, mining, transportation and other enterprises as weighing and measuring equipment of electronic truck scale in the backward status of data processing and other functions, SCS series of all-electronic truck scale display instrument (XK3122 luxury dual display weighing instrument) data communication interface test and analysis research. A weighing data acquisition method based on microcomputer RS232 serial communication interface is proposed, and further combined with RS422\/RS485 serial data communication interface standard and characteristics to achieve remote data acquisition, which has been verified in practical application, and has certain popularization value.
Typical serial communication standards are RS232 and RS485, which define voltage, impedance, etc., but do not define the software protocol, different from RS232, RS485 features include:
1, the electrical characteristics of RS-485: logic \"1\" to the voltage difference between the two lines is (2-6) V; The logic \"0\" is expressed by the voltage difference between the two lines as - (2-6) V. The interface signal level is lower than RS-232-C, it is not easy to damage the chip of the interface circuit, and the level is compatible with the TTL level, which can be easily connected with the TTL circuit.
2, the maximum data transmission rate of RS-485 is 10Mbps.
3, RS-485 interface is a combination of balanced driver and differential receiver, anti-common-mode interference ability is enhanced, that is, anti-noise interference is good.
4, the maximum transmission distance of the RS-485 interface standard value of 4000 feet (about 1219 meters), in fact up to 3000 meters, in addition to the RS-232-C interface on the bus only allows the connection of 1 transceiver, that is, single station capability. The RS-485 interface allows the connection of up to 128 transceivers on the bus. That is, it has multi-station capability, so that users can easily establish equipment networks with a single RS-485 interface. RS-485 can be networked to form a distributed system. The \"number of nodes\" of RS-485 is mainly determined by the \"receiver input impedance\".
485 is a communication protocol, is a Modbus serial interface protocol, it is an industrial communication protocol based on Ethernet. 485 protocol encapsulates data into frame format, using two-way transmission and full-duplex technology, data transmission and control can be carried out between systems.
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It can support a variety of different types of instruments and sensors, can also support a variety of different types of PLC and other computing equipment, providing a flexible system design scheme for system builders. The RS485 bus interface is usually used to achieve 485 communication.
485 is short for USCIS Form I-485, also known as the Application for Adjustment of Status. This form is used to apply for adjustment of nonimmigrant status to lawful permanent resident status in the United States, which is also an application for a green card.
Applicants are required to complete this form and submit it to the USCIS, along with the relevant application materials and fees.