Omron V400-H201 User Manual page 68

Appendices
■ Calculation Programming Example for Sending FCS
DATA$
L
CODE$
A
100
110
120
130
140
150
160
170
180
190
200
■ FCS Check Subroutine Example for Received Data
1000
1010
1020
1030
1040
1050
1060
1070
1080
1090
1100
1110
1120
1130
V400-H101/201
66
User's Manual
Sample data string
Data length
Data character
Exclusive OR
'* * * * * CALCULATE FCS * * * * *
'* FCSSET
L=LEN(DATA$)
A=0
FOR J=1 TO L
CODE$=MID$(DATA$,J,1)
A=ASC(CODE$)XOR A
NEXT J
FCS$=HEX$(A)
IF LEN(FCS$)=1 THEN FCS$="0"+FCS$
RETURN
'* * * * * FCSHECK * * * * *
'* FCSHECK
Q=0:FCSCK$="OK"
PRINT RESPONSE $
LENGS=LEN(RESPONSE$)-3
FCSP$=MID$(RESPONSE$,LENGS+1,2)
FOR J=1 TO LENGS
Q=ASC(MID$(RESPONSE$,J,1))XOR Q
NEXT J
FCSD$=HEX$(Q)
IF LEN(FCSD$)=1 THEN FCSD$="0"+FCSD$
IF FCSD$ < > FCSP$ THEN FCSCK$="ERR"
PRINT "FCSD$=";FCSD$;"FCSP$=";FCSP$;
RETURN
'FCS in response data
'Calculation range of FCS
'FCS calculated in a program
'FCS received correctly: OK
"FCSCK$=";"FCSCK$=" 'FCS not received correctly: ERR