INVT GD310-011P-4-UL, Operation Manual

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GD310-UL series VFD Communication protocol
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“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 VFD to the master)
START T1-T2-T3-T4 (transmission time of 3.5 bytes)
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
Low bit of CRC 7EH
High bit of CRC 9DH
END T1-T2-T3-T4 (transmission time of 3.5 bytes)
The meaning of the response is that:
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 message is received from the VFD 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.
CRC occupies 2 bytes with the fact that the high bit is in the front and the low bit is in the behind.
10.4.2 Command code: 06H
06H (correspond to binary 0000 0110), write one word (Word)
The command means that the master write data to the VFD and one command can write one data
other than multiple dates. The effect is to change the working mode of the VFD.