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(2) Read (receive) data (slave to master)
(a) Command data are converted into ASCII code and transmitted.
(b) Comms byte quantity is 10.
(c) Comms data format (transmission sequence)
S T X
1 byte
・STX (start code)
・Text data
・ETX (end code)
・SUM
(d) Text data details (transmission sequence)
Data
2 byte x 3
6 byte
・Data (note)
Note: Data transfer sequence
Area address
0x01, 0x81
5. Calculation method of checksum
Example
1
STX
STATUS
02
01
1. STAUTUS to DATA are transformed into hexadecimal number on the basis of the ASCII code.
'0'→(30)
'1'→(31)
16
2. STX to ETX are added all.
(02)
+(30)
+(31)
+(46)
+(46)
16
16
16
16
STX STATUS
ID
3. The XOR (Exclusive OR) between the value obtained in 2 clause and (FF)
answer become SUM
(2D7)
XOR (FF)
= （228）
16
16
Text data
6 byte
: Code indicating start of text.
1 byte (02H)
: Transmit / receive data.
6 byte (ASCII code)
: Code indicating end of text.
1 byte (03H)
: XOR result (FFH), of adding STX, Text data, and ETX.
2 byte (ASCII code)
: Sets data to be transmitted.
2 byte x 3 (ASCII code)
Data type
Data bytes
Common data
2
3
ID NO
AREA ADDRESS
FF
01
'4'→(34)
'F'→(46)
16
16
+(30)
+(31)
+(30)
+(34)
16
16
16
16
AREA
RELATIVE
16
E T X
1 byte
10 byte
1st byte
1
Data
2
Upper
3
Upper
4
5
RELATIVE NO
04
00
STX: (02)
16
16
+(30)
+(30)
+(30)
+(30)
16
16
16
16
16
DATA
S U M
2 byte
2nd byte
0x00
Lower
Mid
6
7
ETX
DATA
00
00
03
ETX: (03)
16
+(30)
+(30)
+(03)
＝(2D7)
16
16
16
ETX
are taken, then two column under the
16
3rd byte
0x00
0x00
Lower
SUM
28
16
13
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