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program is written according to the data format obtained, which is often twice the result with
half the effort.
In fact, Modbus-RTU protocol can be regarded as a special kind of free protocol. The
relationship between them is similar to ellipse and circle. We can try to use free format to
realize the function of Modbus instruction.
Example 2: The values of the five registers of a XD3 PLC are sent to the D1-D5 of another
XDM PLC.
If the user understands the Modbus communication, he can use the Modbus-RTU
communication mode to do so, as long as he writes a "write multiple register instructions
(MRGW)" in the host. Here we do it in free communication mode.
Operation steps:
1. Connect the hardware first. Here we use the serial port 2 of the PLC to communicate, that
is, connect A of the two PLC, and connect B of the two PLC.
2. Set the same serial port parameters of the two PLC. The parameters are set as follows.
After setting the parameters, the power can be restarted.
3. XD3 program:
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