INVT GD20-004G-2-EU, Руководство по эксплуатации, Страница: 125 / 168

Goodrive20-EU series VFD Communication protocol
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START T1-T2-T3-T4
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 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 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 high bit in the front and the low bit in the behind.
RTU slave response message (from the VFD 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