Omron 2D CODE READER, User Manual

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104
Appe
ndix
FCS Chec
k Progr
am Example (
B
ASIC)
V400-F050/250/350
User’s Manual
Appendix
FCS Check Program Example (BASIC)
„
Calculation Programming Example for Sending FCS
„
FCS Check Subroutine Example for Received Data
DATA$ Sample data string
L Data length
CODE$ Data character
A Exclusive OR
100 '* * * * * CALCULATE FCS * * * * *
110 '* FCSSET
120 L = LEN (DATA$)
130 A = 0
140 FOR J = 1 TO L
150 CODE$ = MID$ (DATA$,J,1)
160 A = ASC (CODE$) XOR A
170 NEXT J
180 FCS$ = HEX$ (A)
190 IF LEN (FCS$) = 1 THEN FCS$ = "0" + FCS$
200 RETURN
1000 '* * * * * FCSHECK * * * * *
1010 '* FCSHECK
1020 Q = 0: FCSCK$ = "OK"
1030 PRINT RESPONSE $
1040 LENGS = LEN (RESPONSE$) -3
1050 FCSP$ = MID$ (RESPONSE$,LENGS + 1,2) 'FCS in response data
1060 FOR J = 1 TO LENGS 'Calculation range of FCS
1070 Q = ASC (MID$ (RESPONSE$,J,1)) XOR Q
1080 NEXT J
1090 FCSD$ = HEX$ (Q)
1100 IF LEN (FCSD$) = 1 THEN FCSD$ = "0" + FCSD$ 'FCS calculated in a program
1110 IF FCSD$ < > FCSP$ THEN FCSCK$ = "ERR"
1120 PRINT "FCSD$ = "; FCSD$; "FCSP$ = "; FCSP$; 'FCS received correctly: OK
"FCSCK$ ="; "FCSCK$ =" 'FCS not received correctly:
ERR
1130 RETURN