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CHAPTER 6 USING THE COMMUNICATIONS FUNCTION
How to Calculate
FCS
F ASCII → Hex
ASCII
Hex
F Exclusive OR
F Conversion to ASCII code at each digit of the calculation result and setting to FCS
ASCII
Hex
F Completed frame (with appended terminator)
ASCII
Hex
6--6
• End code
Sets the communication results. For details on the types and mean-
ings of end codes, see 6.5 How to Read Communications Error In-
formation (page 6-12).
• FCS (Frame Check Sequence)
Set the frame check results from the start character to the data area.
For details on the frame check, see 6.6 Program Example (page 6-14).
• "*" "CR (Carriage Return) code"
Indicates the end (terminator) of the command or response block.
Calculate the exclusive OR from the start character to the data section. The fol-
lowing describes an example of how to calculate the FCS for "@001000000".
(1) Convert the ASCII codes of each character to Hexadecimal "40H, 30H, ...,
30H".
(2) Calculate the exclusive OR of all characters.
(3) Convert to ASCII code. (→ "4B")
(4) Set the result as FCS.
@
0
0
1
0
40H
30H
30H
31H
30H
40H¨30H¨30H¨31H¨30H¨30H¨30H¨30H¨30H¨30H¨=71H
@
0
0
1
0
40H
30H
30H
31H
30H
@
0
0
1
0
40H
30H
30H
31H
30H
0
0
0
0
0
30H
30H
30H
30H
30H
0
0
0
0
0
30H
30H
30H
30H
30H
0
0
0
0
0
30H
30H
30H
30H
30H
7
1
37H
31H
FCS
7
1
*
CR
37H
31H
2AH 0DH
FCS
Terminator
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