IPE300 series engineering VFD Communication protocol
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T1-T2-T3-T4 (time gap with a min. length of 3.5 bytes)
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.
ADDR=01H means the command message is sent to the VFD with the address of 01H and ADDR
occupies one byte.
CMD=03H means the command message is sent to read data from the VFD and CMD occupies one
byte.
"Start address" means reading data from the address and it occupies two bytes with the MSB on the
left and LSB on the right.
"Data count" indicates the count of data to be read (unit: word). "Start address" is "0004H" and "Data
count" 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 (from the VFD to the master)
T1-T2-T3-T4 (time gap with a min. length of 3.5 bytes)
T1-T2-T3-T4 (time gap with a min. length of 3.5 bytes)
The response information is described as follows:
"ADDR" is "01H", indicating that the message is sent by the VFD whose address is 01H. The ADDR
information occupies one byte.
"CMD" is "03H", indicating that the message is a response of the VFD to the 03H command of the
master for reading data. The CMD information occupies one byte.
"Number of bytes" indicates the number of bytes between a byte (not included) and the CRC byte (not
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