444
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
16 External FX Device – FNC 80 to FNC 89
16.5 FNC 84 – CCD / Check Code
16.5
FNC 84 – CCD / Check Code
Outline
This instruction calculates the horizontal parity value and sum check value in the error check methods used in
communication. There is another check method, CRC (cyclic redundancy check) also. For obtaining CRC
value, use CRC instruction.
→
For CRC instruction, refer to Section 24.4.
→
For complement [NEG (FNC 29) instruction], refer to Section 10.10.
1. Instruction format
2. Set data
3. Applicable devices
Explanation of function and operation
1. 16-bit operation (CCD and CCDP)
The addition data and horizontal parity value of data stored in
to
+n-1 are calculated. The
addition data is stored to
, and the horizontal parity value is stored to
+1.
The 16-bit mode and 8-bit mode are available in this instruction. For the operation in each mode, refer to the
following pages.
Operand type
Description
Data type
Head device number of applicable device
16-bit binary or
character string
Head device number storing the calculated data
16-bit binary or
character string
n
Number of data [setting range: 1 to 256]
16-bit binary
Oper-
and
Type
Bit Devices
Word Devices
Others
System User
Digit Specification
System User
Special
Unit
Index
Con-
stant
Real
Number
Charac-
ter String
Pointer
X Y M T C S D
.b KnX KnY KnM KnS
T
C
D
R U
\G
V
Z Modify K
H
E
"
"
P
3
3
3
3
3 3 3 3
3
3
3
3
3
3 3 3 3
3
n
3 3
3 3
P
FNC 84
CCD
−
−
Mnemonic
Operation Condition
16-bit Instruction
7 steps
CCD
CCDP
Mnemonic
Operation Condition
Continuous
Operation
Pulse (Single)
Operation
32-bit Instruction
S
1
S
D
S
1
S
S
2
D
S
S
D
D
FNC 84
CCD
n
S
Command
input
D