Astraada DRV-24 frequency inverters                                                                  Communication protocol                                                                                   
99 
 
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) 
High bit of writing data 
address 
Low bit of writing data 
address 
RTU slave response message (from the inverter to the master) 
High bit of writing data 
address 
Low bit of writing data 
address 
Note: section 10.2 and 10.3 mainly describe the command format, and the detailed application will 
be mentioned in 10.8 with examples. 
7.3.1.3 Command code 08H for diagnosis 
Meaning of sub-function codes 
Return to inquire information data 
For example: The inquiry information string is same as the response information string when the 
loop detection to address 01H of driver is carried out. 
The RTU request command is: