Bcc Calculation Example - Omron E5AN User Manual

J BCC calculation example
STX
02H
BCC=30H¨30H¨30H¨30H¨30H¨30H¨35H¨30H¨33H¨03H=35H
Calculation result 35H is set to the BCC area.
The ¨ symbol indicates exclusive OR operation and the H indicates hexadecimal code.
J Response frame
Node No.
STX
1
End
Name
code
00 Normal completion
0F FINS command error
10 Parity error
11 Framing error
12 Overrun error
13 BCC error
14 Format error
16 Sub-address error
18 Frame length error
The BCC is formed by converting the 8-bit value obtained by converting
the exclusive OR of the node No. up to ETX into two ASCII characters, and
setting this to the BCC area.
Node No. Sub-address
0(30H) 0(30H) 0(30H) 0(30H) 0(30H) 0(30H) 5(35H) 0(30H) 3(33H)
Sub-address
2 2
The command ended normally without error.
The specified FINS command could not be executed.
The FINS response code should indicate why the command
could not be executed.
The sum total of bits whose received data is "1" does not
match the set value of "communications parity."
Stop bit is "0".
An attempt was made to transfer new data when the recep-
tion data was already full.
The calculated BCC value is different from the received BCC
value.
· The command text contains characters other than 0 to 9,
and A to F. This error is not applicable to the echoback test.
(For details, see chapters 2.3 "Echoback test.")
· No SID and command text. Or, no command text
· "MRC/SRC" not included in command text
· Illegal (unsupported) sub-address
· No sub-address, SID and command text
· Sub-address less than two characters, and no SID and
command text
The received frame exceeds the fixed (supported) number of
bytes.
· The end code is returned to received command frames addresses to the
self node.
· No response will be returned if all the items in the response frame are
incomplete up to the ETX and BCC.
· "Error Detection Priority" indicates the priority when two or more
errors occur simultaneously.
SID Command text
End code Command text
2
Description
2.1 Data Format
ETX BCC
03H 35H
BCC
ETX
1 1
Error
Detection
Priority
None
8
2
1
3
5
7
6
4
2--3