IDEC High Performance Series - Manual (Page 167)

WindO/I-NV2 User’s Manual 3-65
5 User Communication
3
Communic
ation
• Number of bytes and comparison data
When the converted data is 3034h, the data used for comparison with the BCC part of the receive data is as
follows.
• BCC data comparison
The comparison data is compared with the BCC part of the receive data.
In the following receive data, when the comparison data is the 1-byte 34h, there is a match since the BCC part data
is 34h.
When there is no match, the BCC Error (address+0, bit 0) of the Status Device changes to 1.
• When the calculation type is Modbus ASCII (LCR)
When the BCC calculation result is 4241h after Binary (HEX) to ASCII conversion the resulting two bytes of
data is used for comparison with the BCC part of the receive data.
• When the calculation type is Modbus RTU (CRC)
When the BCC calculation result is BA30h with no conversion the two bytes of data is used for comparison with
the BCC part of the receive data.
0
(30h)
4
(34h)
Comparison data
4
(34h)
Bytes: 1
Converted data
(Second byte) (First byte)
0
(30h)
4
(34h)
0
(30h)
4
(34h)
Comparison data
Bytes: 2
Converted data
(Second byte) (First byte)
1
(31h)
4
(34h)
5
(35h)
2
(32h)
STX
(02h)
3
(33h)
BCC
(34h)
CR
(0Dh)
Comparison data
Match
Receive data BCC part
4
(34h)
B
(42h)
A
(41h)
B
(42h)
A
(41h)
Comparison data
4241h
Binary (HEX) to ASCII
Data
Bytes: 2
Converted data
(Second byte) (First byte)
BAh 30h BAh 30h
BA30h
No conversion
Comparison data
Data
Bytes: 2
Converted data
(Second byte) (First byte)