CHV180 series frequency inverter special for elevator Communication protocol
.100.
address 1.
Node addr.
Command
Data addr.
Read No.
CRC
0x01
0x03
0x00
0x02
0x00
0x01
0x25
0xCA
The table below shows the reply frame from slave node address 1.
Node addr.
Command
Bytes No.
Data
CRC
0x01
0x03
0x02
0x00
0x00
0xB8
0x44
ASCII mode
In ASCII mode, the frame head is “0x3A”, and default frame tail is “0x0D” or “0x0A”. The
frame tail can also be configured by users. Except frame head and tail, other bytes will
be sent as two ASCII characters, first sending higher nibble and then lower nibble. The
data have 7/8 bits. “A”~“F” corresponds to the ASCII code of respective capital letter.
LRC check is used. LRC is calculated by adding all the successive bytes of the message
except the head and tail, discarding any carriers, and then two’s complementing the
result.
Example of Modbus data frame in ASCII mode:
The command frame of writing 0x0003 into address “0x1000” of slave node address 1 is
shown in the table below:
LRC checksum = the complement of (01+06+10+00+0x00+0x03) = 0xE5
Frame head
Node addr.
Command
Data addr.
Code
0
1
0
6
1
0
0
0
ASCII
3A
30
31
30
36
31
30
30
30
Data to write
LRC
Frame tail
0
0
0
3
E
5
CR
LF
30
30
30
33
45
35
0D
0A
10.4 Protocol function
Different respond delay can be set through drive’s parameters to adapt to different needs.
For RTU mode, the respond delay should be no less than 3.5 bytes interval, and for
ASCII mode, no less than 1ms.
The main function of Modbus is to read and write parameters. The Modbus protocol
supports the following commands:
0x03
Read inverter’s function parameter and state parameters
0x06
Write single function parameter or command parameter to inverter
All drive’s function parameters, control and state parameters are mapped to Modbus
R/W data address.
