Delta DVP-ES2/EX2/SS2/SA2/SX2/SE manual Ccd, Check Code

3. Instruction Set

API

84

Mnemonic			Operands	Function
	CCD	P		Check Code

Controllers

ES2/EX2 SS2 SA2 SX2

SE

Type

Bit Devices

Word devices

Program Steps

OP

X

Y

M

S

K

H

KnX

KnY

KnM

KnS

T

C

D

E

F

CCD, CCDP: 7 steps

S

*

*

*

*

*

*

*

D

*

*

*

*

*

n

*

*

*

16-bit

PULSE

32-bit

ES2/EX2

SS2

SA2

SX2

ES2/EX2

SS2

SA2

SX2

ES2/EX2

SS2

SA2

SX2

SE

SE

SE

Operands:

S: source data D: Destination device for storing check sum

n: Number of byte (n = 1~256)

Explanations:

1.This instruction performs a sum check for ensuring the validity of the communication data.

2.16-bit conversion: If M1161 = OFF, n bytes of data starting from low byte of S will be summed up, the checksum is stored in D and the parity bits are stored in D+1.

3.8-bit conversion: If M1161 = ON, n bytes of data starting from low byte of S (only low byte is valid) will be summed up, the check sum is stored in D and the parity bits are stored in D+1.

Program Example 1:

1.M1161 = OFF, 16-bit conversion.

2.When X0 = ON, 6 bytes from low byte of D0 to high byte of D2 will be summed up, and the checksum is stored in D100 while the parity bits are stored in D101.

M1000

M1161

X0

CCD D0 D100 K6

(S)Content of data

D0 low byte			K100 = 0 1 1 0 0 1 0 0
D0 high byte			K111 = 0 1 1 0 1 1 1 1
D1 low byte			K120 = 0 1 1 1 1 0 0 0
D1 high byte			K202 = 1 1 0 0 1 0 1 0
D2 low byte			K123 = 0 1 1 1 1 0 1
D2 high byte			K211 = 1 1 0 1 0 0 1
D100			K867						Total
D101				0 0 0 1 0 0 0 1							The parity is 1 when there is an odd number of 1.
											The parity is 0 when there is an even number of 1.
D100	0	0	0	0	0	0	1	1		0	1	1	0	0	0	1	1
D101 0		0	0	0	0	0	0	0		0	0	0	1	0	0	0	1	Parity

3 - 2 3 5