Series 2000 Communications Handbook - Soliton
Series 2000 Communications Handbook - Soliton
Series 2000 Communications Handbook - Soliton
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MODBUS and JBUS Protocol<strong>Series</strong> <strong>2000</strong> <strong>Communications</strong> <strong>Handbook</strong>3.11. EXAMPLE OF A CRC CALCULATION IN BASICLANGUAGEFunction CRC(message$) as long'' CRC runs cyclic Redundancy Check Algorithm on input message$'' Returns value of 16 bit CRC after completion and'' always adds 2 crc bytes to message'' returns 0 if incoming message has correct CRC'' Must use double word for CRC and decimal constantscrc16& = 65535FOR c% = 1 to LEN(message$)crc16& = crc16& XOR ASC(MID$(message$, c%, 1))FOR bit% = 1 to 8IF crc16& MOD 2 THENcrc16& = (crc16& \ 2) XOR 40961ELSEcrc16& = crc16& \ 2END IFNEXT BIT%NEXT c%crch% = CRC16& \ 256: crcl% = CRC16& MOD 256message$ = message$ + CHR$(crcl%) + CHR$(crch%)CRC = CRC16&END FUNCTION CRC3-12 <strong>Series</strong> <strong>2000</strong> <strong>Communications</strong> <strong>Handbook</strong> Part No HA026230 Issue 2.0 Feb-00
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