28
MG.10.P2.22
VLT is a registered Danfoss trade mark
Read
Holding
Registers
(03
HEX
)
Description
Reads the binary contents of holding registers
(4x references) in the slave. Broadcast is never
supported for reads.
Query
The query message specifies the starting
register and quantity of registers to be read.
Registers are addressed starting at zero.
Registers 1-4 are addressed as 0-3.
Example of a request to read registers 40001-03 from slave device 01.
Field Name
Example (HEX)
Slave Address
01
Function
03
Starting Address HI
00
Starting Address LO
00
No. of Points HI
00
No. of Points LO
03
Error Check (CRC)
–
Response
The register data in the response message
are packed as two bytes per register, with the
binary contents right justified within each byte.
For each register, the first byte contains the
high order bits and the second contains the
low order bits.
Field Name
Example (HEX)
Slave Address
01
Function
03
Byte Count
06
Data HI (Register 40001)
55
Data LO (Register 40001)
AA
Data HI (Register 40002)
55
Data LO (Register 40002)
AA
Data HI (Register 40003)
55
Data LO (Register 40003)
AA
Error Check (CRC)
–
APPENDIX A
