Communication example between upper computer and Mitsubishi fn2x

According to the needs of the project, the upper computer software and Mitsubishi PLC communicate ,C# and PLC It's all zero base ,

C# The learning process is brief , It's not hard to , Just learn space

The following is a brief description and PLC Key steps of communication ：

1、 Serial port settings ：

1) Serial line （ Mitsubishi's 422 Line ）

2） Serial tools

Baud rate ：9600 （PLC Is constant ）

Parity test ： Even check   （PLC fixed ）

Data bits ：7 

Stop bit ：1

2、 Communication test

Upper computer ： send out 0x05

PLC： Respond 0x06（ normal ）  return 0x15  The instruction is invalid , Look at your serial port settings

3、 obtain x Current status of points

1） Communication format

read ：

STX	CMD	x/y Address （4 byte ）				Read a few bytes		EXT	check
0x02	'0' read     /   '1'  Write	‘0’	'0'	'A'	'0'	‘0’	‘2’	0x03	‘6’ crc1	‘6’ crc2
Fixed value 0x02	0x30 /0x31	0x30	0x30	0x41	0x30	0x30	0x32	Fixed value	0x36	0x36

 

notes ： ‘A’ direct turn asiic code   Put the characters   ‘9’-9= 0x30   ‘A’ - 0x0a = 0x31, Notice here , When calculating, we should treat them differently

Check value calculation ：CMD+ Address values + Read byte value +ext = The sum of the

 

 temp =  The sum of the &0xff 

            a = ((temp >> 4) & 0x0f) > 9 ? ((temp >> 4) & 0x0f) + 7 : ((temp >> 4) & 0x0f);
            b = (temp & 0x0f) > 9 ? ((temp & 0x0f) + 7) : (temp & 0x0f);
            crc1= (byte) ( a + 0x30);
            crc2= (byte)( b + 0x30);

PLC return ：

Erroneous return ：0x15

Successfully returns ：

 

STX	The first value		Second value		EXT	check
0x02	‘3’	'5'	'8'	'4'	0x03	‘D’ crc1	‘7’ crc2
Fixed value 0x02	0x33	0x35·	0x38	0x34	Fixed value	0x44	0x37

The first value ：

y7	y6	y5	y4	y3	y2	y1	y0
0	0	1	1	0	1	0	1
3				5

 

Second value

y17	y16	y15	y14	y13	y12	y11	y10
1	0	0	0	0	1	0	0
8				4

Multibyte isomorphism 2 Byte way

Write ：

STX

CMD

x/y Address （4 byte ）

Read a few bytes

The first value

Second value

EXT

check

0x02

'   '1'  Write

‘0’

'0'

'A'（Y Address ）

'0'

‘0’

‘2’

‘3’

‘5’

‘8’

‘4’

0x03

‘6’ crc1

‘6’ crc2

Fixed value 0x02

0x31

0x30

0x30

0x41

0x30

0x30

0x32

0x33

0x35

0x38

0x34

Fixed value

0x33

0x42

The first value ：

y7	y6	y5	y4	y3	y2	y1	y0
0	0	1	1	0	1	0	1
3				5

Second value ：
 

y17	y16	y15	y14	y13	y12	y11	y10
1	0	0	0	0	1	0	0
8				4

Write success returns ：0x06

Write failure returns ：0x15

 

 

PLC The corresponding relationship between register points ：

x:  0x0080

y:0x00a0