The value in START and END is "T1-T2-T3-T4 (transmission time of 3.5 bytes)", indicating that the
RS485 needs to stay idle for at least the transmission time of 3.5 bytes. An idle time is required to
distinguish on message from another to ensure that the two messages are not regarded as one.
The value of ADDR is 01H, indicating that the command is transmitted to the VFD whose address is
01H. The ADDR information occupies one byte.
The value of CMD is 03H, indicating that the command is used to read data from the VFD. The CMD
information occupies one byte.
"Start address" indicates that data reading is started from this address. It occupies two bytes, with the
MSB on the left and LSB on the right.
"Data quantity" indicates the quantity of data to be read (unit: word).
The value of "Start address" is 0004H, and that of "Data quantity" is 0002H, indicating that data is to
be read from the data addresses of 0004H and 0005H.
CRC check occupies two bytes, with the LSB on the left, and MSB on the right.
RTU slave response (transmitted by the VFD to the master)
The definition of the response information is described as follows:
The value of ADDR is 01H, indicating that the message is transmitted by the VFD whose address is
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