Astraada AS24DRV4075, Operation Manual

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Astraada DRV-24 frequency inverters Communication protocol
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ADDR 01H
CMD 03H
High bit of the start address 00H
Low bit of the start address 04H
High bit of data number 00H
Low bit of data number 02H
CRC low bit 85H
CRC high bit CAH
END T1-T2-T3-T4
T1-T2-T3-T4 between START and END is to provide at least the time of 3.5 bytes as the leisure time
and distinguish two messages for the avoidance of taking two messages as one message.
ADDR = 01H means the command message is sent to the inverter with the address of 01H and
ADDR occupies one byte
CMD=03H means the command message is sent to read data from the inverter and CMD occupies
one byte
“Start address” means reading data from the address and it occupies 2 bytes with the fact that the
high bit is in the front and the low bit is in the behind.
“Data number” means the reading data number with the unit of word. If the “start address’ is
0004H and the “data number” is 0002H, the data of 0004H and 0005H will be read.
CRC occupies 2 bytes with the fact that the high bit is in the front and the low bit is in the behind.
RTU slave response message (from the inverter to the master)
START T1-T2-T3-T4
ADDR 01H
CMD 03H
Byte number 04H
Data high bit of address
0004H
13H
Data low bit of address
0004H
88H
Data high bit of address
0005H
00H
Data low bit of address
0005H
00H
CRC CHK low bit 7EH
CRC CHK high bit 9DH
END T1-T2-T3-T4
The meaning of the response is that:
ADDR = 01H means the command message is sent to the inverter with the address of 01H and
ADDR occupies one byte
CMD=03H means the message is received from the inverter to the master for the response of
reading command and CMD occupies one byte
“Byte number” means all byte number from the byte(excluding the byte) to CRC byte(excluding the
byte). 04 means there are 4 byte of data from the “byte number” to “CRC CHK low bit”, which are
“digital address 0004H high bit”, “digital address 0004H low bit”, “digital address 0005H high bit”
and “digital address 0005H low bit”.
There are 2 bytes stored in one data with the fact that the high bit is in the front and the low bit is in
the behind of the message, the data of data address 0004H is 1388H,and the data of data address
0005H is 0000H.