Access control construction wiring considerations

Reader installation and wiring precautions. The reader should not be mounted on the metal surface as much as possible. If it is mounted on a metal surface, the reading distance will be greatly attenuated and the card will not be read. If it must be installed on a metal surface, use a rubber cover to raise the reader 1 to 2 cm. Two-way card reader distance ≥ 30 cm (avoid back-to-back horizontal installation). The distance between two-way card readers is too close to make readers insensitive.

All the cables are recommended to use sleeves. Both PVC pipe and galvanized pipe can be used to prevent the signal from being caught and the mouse biting off the line to cause a malfunction. Especially when wiring with strong electric power, pay attention to keeping a certain distance from the strong electric power and casing.

485 communication must use twisted pair, which is determined by the 485 communication principle. Twisted pair can make the communication quality the most stable, the longest transmission distance, the strongest anti-jamming ability.

The line to the controller requires the use of a two-core power cable (disabled cable) with a cross-sectional area of ​​1.0 mm2 or more. If more than 50 meters or two locks are connected in parallel, consider using thicker wires or multiple parallel connections. The diameter of the cable is thin and the resistance value is large. For a long time, it is most likely that people will not open their doors and shut people in or out of doors. When we cut off the power supply and reconnect it again, it's normal again, but after a few days, the problem has again arisen. In addition to the electric lock line, other lines can use network cable.

Why should the 485 bus be connected in series with the hand, but not in parallel?

The 485 bus uses a hand-in-hand series connection, which is also regulated by the 485 communication principle. Hand-in-hand series, to ensure the most stable 485 communication quality. With the star-parallel structure, the terminals on the bus will generate reflected signals, which will affect the stability of 485 communications. The most common phenomenon is that sometimes the terminal can be searched, sometimes it cannot be found, and it is unstable.