Bcc Calculation Example; Response Frame - Omron E5C-T Series Communications Manual

2-1-2

BCC Calculation Example

The BCC (Block Check Character) is determined by calculating the exclusive OR of the bytes from the
node number up to ETX. The 8-bit result is written to the BCC byte at the end of the frame.
STX
Node number
02H 0 (30H) 0 (30H)
BCC = 30H+30H+30H+30H+30H+30H+35H+30H+33H+03H = 35H
The result of the calculation (35 hex) is written to the BCC byte.
The + symbols indicate XOR (exclusive OR) operations.
2-1-3

Response Frame

Node number Sub-address End code
STX
1
End code Name
00 Normal completion
FINS command error
0F
Parity error
10
11 Framing error
Overrun error
12
BCC error
13
Format error
14
Sub-address error
16
Frame length error
18
• An end code is returned for each command frame received that was addressed to the local node.
• No response will be returned unless the frame contained all elements up to the ETX and BCC.
• "Error Detection Priority" indicates the priority when two or more errors occur simultaneously.
E5C-T Digital Temperature Controllers Programmable Type Communications Manual (H186)
Sub-address
0 (30H) 0 (30H) 0 (30H) 0 (30H) 5 (35H) 0 (30H) 3 (33H)
0 0
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 the "communications parity" bit.
Stop bit is "0."
An attempt was made to transfer new data when the
reception data buffer 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 does not apply to Echoback Tests.
(Refer to 2-3-7 Echoback Test for details.)
• There was no SID and command text. There was no
command text.
• "MRC/SRC" not included in command text.
• Illegal (unsupported) sub-address
• There was no sub-address, SID, and command text.
• Sub-address was less than two characters, and there was
no SID and command text
The received frame exceeds the specified (supported)
number of bytes.
2 CompoWay/F Communications Procedures
SID
Command text
Command text
2
Description
ETX BCC
03H 35H
BCC
ETX
1 1
Error detection
priority
None
8
2
1
3
5
7
6
4
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2