Hardware Connection Of The First Communication Method - Ebyte K62-DL20 User Manual

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and suppress interference;
(3) The earth connection should conform to the national standard. If it is not guaranteed whether the ground connection
conforms to the national standard, it is recommended that the PE of this product is not connected to the ground to prevent
interference or even damage to the product.

3.2 Hardware connection of the first communication method

The first communication method: 485
(1) 485 function
1. Configure product parameters;
2. Adopt RS485 remote transmission (pair transmission) products;
3. After the "RS485 transparent transmission" function is enabled, data transparent transmission is performed;
(For details, see " Product Basic Parameter Read and Change Write " and " Mode Configuration " " (2) Transparent
Transmission " and " (3) 485 Transparent Transmission Filtering " in the " Parameter Description " chapter ).
(2) 485 hardware connection
Wiring connection: 485 wiring is very simple; just connect the 485 communication product A to A, B to B, and the wiring
is completed. For the wiring diagram, see Figure 3-1 above.
(3) 485 parameter value options
1. Baud rate: 1200, 2400, 4800, 9600 (default), 14400, 19200, 38400, 43000, 56000, 57600, 115200
2. Check digit: None (default), Odd, Even, Mark, Space
3. Data bits: 6, 7, 8 (default)
4. Stop bit: 1 (default), 2
(4) Product 485 Hardware Protection
This product 485 has the capabilities of overcurrent protection, power surge protection, inductive lightning protection,
and EMC electromagnetic compatibility.
(5) 485 bus wiring rules
1. With the extension of transmission distance, echo reflection signals will be generated on the 485 bus network. If
the transmission distance of the 485 bus exceeds 100 meters, it is recommended to connect a 120 Ω resistor in
parallel at the beginning and end of the 485 network .
2. In industrial field applications, if the on-site interference source is very complex, there may be a high common-mode
voltage between nodes. Although the 485 interface uses a differential transmission method, it has the ability to resist
common mode interference. But when the common mode voltage is greater than +12V or less than -9V, it exceeds the
limit receiving voltage of the 485 receiver, the receiver will not work, and may even burn the chip and equipment. At this
time, 485 opto-isolated repeaters should be used in the 485 bus network to eliminate the effect of common mode voltage.
3. Since the 485 bus transmits a pair of differential signals, the data transmission line between each device on the 485
network is best to use a twisted pair with an additional shielding layer, and the shielding layer should be reliably
grounded at one point.
4. In the simple application of the 485 bus, the bus-type topology wiring method is generally used. But in a more
complex system, the wiring construction of the bus topology is not only very cumbersome, but also wastes a lot of
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