The connection method of the 120Ω matching resistance of the dome terminal is as follows: The 120Ω matching resistance of the dome terminal can be connected by the dial switch on the chassis of the dome. As shown below. When the dome camera leaves the factory, the 120Ω matching resistance is not connected by default. The specifications of the shielded twisted pair used are related to the distance of the 485 communication line and the number of connected devices, as shown in the following table. 485- of the last 485 device to improve the communication quality. 12V. If it exceeds this range, the communication will be affected, and the communication interface will be damaged severely. Therefore the trigger level of the RS232 interface is set relatively high at ±3 Volt. • UART interface support for 7 or 8 data bits, what is rs485 cable 1 or 2 stop bits and odd / even / mark / space / no parity. • Low operating and USB suspend current. There are many applications of RS485 in weak current intelligent engineering, and the most common applications are in access control systems, BA systems, intelligent lighting systems, parking lot management systems, etc. With the continuous popularization of digital networks, RS485 is now less and less used in weak current applications.

● The manufacturer will do a lot of testing work for its supporting 485 converter, and will require the 485 converter manufacturer to carry out production and quality testing according to its fixed performance parameters, so it has better compatibility with access control equipment. In theatre and performance venues, RS-485 networks are used to control lighting and other systems using the DMX512 protocol. This includes speed control using Variable Frequency Drives (VFD) or inverters, as well as controlling simple PLC and HMI network systems. RS485, CAN bus to build network with both of the signal/power in two wires (total bus can provide 960 watt power and 12 watt in every terminal). The length of the branch line from the bus to each terminal device should be as short as possible, generally not exceeding 5 meters. Simply pull a line to the device alone, which can be used to rule out whether the wiring is causing the communication failure. It requires minimal wiring and can share the wiring among several seats, reducing weight. Before debugging, make sure that the wiring of the equipment is correct and the construction conforms to the specifications. ● Carry out construction strictly in accordance with the 485 bus construction specification to prevent any fluke.

Most engineering companies are accustomed to using Category 5 network cables or over Category 5 network cables as 485 communication lines, which is wrong. The star structure will produce reflected signals, which will affect the 485 communication. 4) Why should the 485 bus adopt the hand-in-hand structure instead of the star structure? Star and ring topologies are not recommended because of signal reflections or excessively low or high termination impedance. Ensure a single, continuous signal channel as a bus. How many devices can be connected to a bus? For instance, consider devices A and B. During a specific timeframe, data transmission is allowed from A to B, and once completed, data transmission from B to A can take place. Ensure power and data lines are connected properly and there are no loose connections. Differential mode interference is transmitted between two signal lines and belongs to symmetrical interference. In the transmission process, the method of adding relays can be used to amplify the signal.

If you’re looking for a low data transmission speed over a short distance, the RS232 will suffice, even though it is slightly archaic. In fact, there is no such thing as an RS485 cable since RS485 is a protocol for serial communication (like between inverter and Zero export device) and Ethernet is a protocol for carrying internet data (between router and inverter) whereas CAT6 is a cable standard. For example you need to consider the noise level in the environment surrounding the serial converter. And what is a RS232 to RS422 converter? Accessories available are a 12VDC Switching Power Supply(Wall Wart), an enclosure, and a 7ft DB9F to RJ11/12 RS232 cable. They would supply all of your electrical requirements; You’re sure to find what you need in our broad selection of electrical & electronics, including electronic components, electrical & Telecommunication equipment and electromechanical devices. ● On-site debugging with complete debugging equipment. 3) What are the debugging methods for failure? RS-485 signals are used in a wide range of computer and automation systems.