B&B Electronics MODSCAN32 - Manual - Manual (Page 13)

13
LRC (Longitudinal Redundancy Check)
The error check sequence for the ASCII mode is LRC. The error check is an 8-bit binary number
represented and transmitted as two ASCII hexadecimal (hex) characters. The error check is produced by
converting the hex characters to binary, adding the binary characters without wraparound carry, and two’s
complementing the result. At the received end the LRC is recalculated and compared to the sent LRC. The
colon, CR, LF, and any imbedded non-ASCII hex characters are ignored in calculating the LRC.
Address
02 0000 0010
Function 01 0000 0001
Start Add H.O. 00 0000 0000
Start Add L.O. 00 0000 0000
Quantity of Pts 00 0000 0000
08 0000 1000
Sum 0000 1011
1’s complement 1111 0100
+1 0000 0001
Error Check F5 2’s complement 1111 0101