INVT GD20-0R4G-S2 User Manual

Goodrive20 inverters
Communication protocol
103
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.
CRC occupies 2 bytes with the fact that the high bit is in the front and the low bit is in the behind.
7.3.1.2 Command code:06H
06H(correspond to binary 0000 0110), write one word(Word)
The command means that the master write data to the inverter and one command can write one data other
than multiple dates. The effect is to change the working mode of the inverter.
For example, write 5000 (1388H) to 0004H from the inverter with the address of 02H, the frame structure is
as below:
RTU master command message (from the master to the inverter)

INVT GD20-0R4G-S2 Specifications

General

Brand	INVT
Model	GD20-0R4G-S2
Category	DC Drives
Language	English