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15 Modbus Kommunikations-Protokoll
Request from master:
Contents
Size (bytes)
Data Range
0x01...0xF9
Response from slave:
Contents
Size (bytes)
Data Range
0x01...0xF9
Remarks:
1) N = number of registers requested
2) The CRC check code of this instrument is obtained by CRC-16-IBM (polynomial
X16 + X15 + X2 + 1, mask word 0xA001) cyclic redundancy algorithm. The low
byte of the check code is first, and the high byte is after.
Type of byte order: MID-LITTLE-ENDIAN:
Type of byte order
MID-LITTLE-ENDIAN
LITTLE-ENDIAN
BIG-ENDIAN
24
Slave
Function code
address
1
0x03 (read)
0x06 (write)
Slave
Function code
address
1
0x03 (read)
0x06 (write)
Byte sequencing (HEX)
15 Modbus Kommunikations-Protokoll
Register
address
1
0x0000...0xFFFF 0x00...0x7D
Data size
1
2 x N
C D A B
D C B A
A B C D
Number of
registers
2
2
Data
1
2 x N
1)
---
Example
0x 0A 11 42 C5
0x 11 0A C5 42
0x 42 C5 0A 11
Check
code
2
CRC
Check
code
1)
2
CRC
2)
S462
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