464
FX3G/FX3U/FX3UC 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
S: This function is supported only in FX3U/FX3UC PLCs.
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
proceeding 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
XYMTCSD
.b KnX KnY KnM KnS T C D R
U\G
V Z Modify K H E "
"P
33333333 S3
3333333 3
n33 33
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 nS
Command
input
D