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FX3S/FX3G/FX3GC/FX3U/FX3UC Series
Programming Manual - Basic & Applied Instruction Edition
24 Others – FNC181 to FNC189
24.4 FNC188 – CRC / Cyclic Redundancy Check
24.4 FNC188 – CRC / Cyclic Redundancy Check
Outline
This CRC instruction calculates the CRC (cyclic redundancy check) value which is an error check method used in
communication.
In addition to CRC value, there are other error check methods such as parity check and sum check. For obtaining the
horizontal parity value and sum check value, CCD (FNC 84) instruction is available.
For the generation of CRC value (CRC-16), the CRC instruction uses “X
16
+ X
15
+ X
2
+ 1” as a polynomial and uses
"FFFFH" as a default value.
→ For CCD instruction (check code), refer to Section 16.5.
1. Instruction format
2. Set data
3. Applicable devices
S: Make sure to specify four digits (K4) when specifying the digits of a bit device.
Explanation of function and operation
1. 16-bit operation
CRC value is generated for “n” 8-bit data (unit: byte) starting from a device specified in , and stored to .
The 8-bit conversion mode and 16-bit conversion mode are available in this instruction, and the mode can be switched
by turning ON or OFF M8161. For the operation in each mode, refer to the following pages.
Operand Type Description Data Type
Head device number storing data for which the CRC value is generated
16-bit binary
Device number storing the generated CRC value
n
Number of 8-bit (1-byte) data for which the CRC value is generated or the device number
storing the number of data
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
SSSS
SSS
n
P
FNC 188
CRC
Mnemonic Operation Condition
16-bit Instruction
7 steps
CRC
CRCP
Mnemonic Operation Condition
Continuous
Operation
Pulse (Single)
Operation
32-bit Instruction
⎯
⎯
S
D
S
D
S
D
FNC188
CRC
n
Command
input
D
S