Supported Modbus Rtu Function Codes - Danfoss VLT 5000 Instruction Manual

Supported Appendix A describes the following functions
supported by the Modbus RTU option card.
Modbus RTU
Function
Read Coil Status (01
Codes
Force Single Coil (05
Force Multiple Coils (0F
Read Coil Description
Reads the ON/OFF status of discrete outputs
Status
(0X references, coils) in the slave. Broadcast
(01 )
is never supported for reads.
HEX
Query
The query message specifies the starting coil
and quantity of coils to be read. Coils are
addressed starting at zero. Coils 1-16 are
addressed as 0-15.
Example of a request to read coils 1-16 from slave device 01.
Response
The coil status in the response message is
packed as one coil per bit of the data field.
Status is indicated as: 1 = ON; 0 = OFF. The
LSB of the first data byte contains the coil
addressed in the query. The other coils follow
toward the high order end of this byte, and
from 'low order to high order' in subsequent
bytes.
24
All manuals and user guides at all-guides.com
APPENDIX A
)
HEX
)
HEX
)
HEX
Field Name
Slave Address
Function
Starting Address HI
Starting Address LO
No. of Points HI
No. of Points LO
Error Check (CRC)
Field Name
Slave Address
Function
Byte Count
Data (Coils 8-1)
Data (Coils 16-9)
Error Check (CRC)
Read Holding Registers (03
Preset Single Register (06
Preset Multiple Registers (10
Example (HEX)
01
01
00
00
00
10
–
If the returned coil quantity is not a multiple
of eight, the remaining bits in the final data
byte will be padded with zeros (toward the
high order end of the byte). The Byte Count
field specifies the quantity of complete bytes
of data.
Example (HEX)
01
01
02
55
AA
–
MG.10.P2.22 - VLT is a registered Danfoss trademark
)
HEX
)
HEX
)
HEX