smartmicro UMRR-0C Type 42 - Page 14

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UMRR-0C Type 42 User Manual USA-Canada_100MHz.docx Version 2 I Page 14 of 19 I November 22, 2017
Table 3: RS485 message structure
Byte\Bit
7
6
5
4
3
2
1
0
0
Start sequence (4 x UINT8)
0xCA
1
0xCB
2
0xCC
3
0xCD
x
Data payload (n x UINT8)
x
x
x
x
x
x
x
0
XOR Checksum (UINT8)
1
End sequence (4 x UINT8)
0xEA
2
0xEB
3
0xEC
4
0xED
Every data message consists of its own message ID, the number of used data bytes and the
data bytes itself.
The checksum is calculated on all data except the start sequence and the end sequence. The
Checksum is a simple XOR Assignment of all n data bytes.
Byte0 XOR Byte1 XOR Byte2 ... XOR Byte (n-1)