Hitachi SJ700D-004L, Instruction Manual

Page: 199 / 288

Chapter 4 Explanation of Functions
4-128
(3) How to calculate the block check code (BCC)
(Example) When using the 01 command (frequency-setting command) to set the inverter output frequency to
5 Hz (the station No. of the inverter is 01):
STX Station No. Command Data BCC CR
ASCII code
(Hex)
(02)
01 (30 31)
01 (30 31)
000500 (30 30 30 35 30 30)
05
(Hex)
(30 35)
(0D)
The contents of "Station No." to "Data" are converted into ASCII data, and the ASCII data is XORed bit by bit. The final
XOR result is set as the block check code (BCC). In the above Example of transmission frame, BCC is calculated as
follows:
30 31 30 31 30 30 30 35 30 30 (HEX)
(Reference) ASCII code conversion table
Character data ASCII code(HEX) Character data ASCII code(HEX)
STX 02 A 41
ACK 06 B 42
CR 0D C 43
NAK 15 D 44
0 30 E 45
1 31 F 46
2 32 H 48
3 33 P 50
4 34 b 62
5 35
6 36
7 37
8 38
9 39
note) (Hex) meas hexadecimal.
05 (This result is used as BCC.)(HEX)
Transmission frame configuration
Xor
01
Xor
31
Xor
00
Xor
30
Xor
30
Xor
05
Xor
35
Xor
00
Xor