66
4. Parameter description
Parameter
Step 4. After processing, for information out of range, inverter replies to computer that this
information is incorrect, using the format D:
NAK
Station number
0
Error Code
H0C
CR
H15
H30 H30
H43
H0D
2. Modbus protocol
1). Information form
● Modbus serial transmission can be divided into two kinds. There are ASCII (American Standard
Code for Information Interchange) and RTU (Remote Terminal Unit) mod.
Query Msssage
PC
（
Master
）
INV
（
Slave
）
Single
Response Message
ASCII
：
CR
、
LF
RTU
：
wait times >= 10ms
Response time for
INV
Query Messsage
PC
（
Master
）
INV
（
Slave
）
Broadcast
No Response
(1). Query
PC (primary address) sends a message to the inverter (from the address) which is on the specified address.
(2). Normal Response
After sending a query to receive from PC, inverter to perform the requested function corresponds to the PC
and return to the normal response.
(3). Error Response
Inverter received an invalid function code, address, data, response returned to the PC.
(4). Broadcast
PC designated by the address 0, can send a message to all the inverters. All inverters which received
information from PC performed the requested function, but do not respond to the PC.
2). Communication format
● The master transmited the Query Message to inverter, the inverter response message to the PC, the
address and function code will be copied when normal communication. Bit 7 of function will be
set 1(=H80) and Data Byte will be set by error code when abnormal communication.
● Message form
：
Mode
Start
①
Address
②
Function
③
Data
④
Error check
End
ASCII
H3A
8 Bit
8 Bit
n
×
8 Bit
2
×
8 Bit
0D 0A
RTU
>=10ms
>=10ms
