Mitsubishi Electric MELSEC FX3U - Page 624

622
FX3G/FX3U/FX3UC Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
24 Others – FNC181 to FNC189
24.4 FNC188 – CRC / Cyclic Redundancy Check
16-bit conversion mode (while M8161 is OFF)
In this mode, the operation is executed for high-order 8 bits (1 byte) and low-order 8 bits (1 byte) of a device
specified in .
The operation result is stored to one 16-bit device specified in .
Example: = D100
=D0
n = 6
Device
Contents of target data
8 bits 16 bits
Device storing data for
which the CRC value is
generated
Low-order byte Low-order bits of D100 01H
0301H
High-order byte High-order bits of D100 03H
+1
Low-order byte Low-order bits of D101 03H
0203H
High-order byte High-order bits of D101 02H
+2
Low-order byte Low-order bits of D102 00H
1400H
High-order byte High-order bits of D102 14H
... ...
–
+n/2-1
Low-order byte
–
High-order byte
Device storing the
generated CRC value
Low-order byte Low-order bits of D0 E4H
41E4H
High-order byte High-order bits of D0 41H
S
D
16-bit conversion mode
FNC188
CRC
n
M8161
M8000
Command
input
D 
S 
S
D
S
S
S
S
D