Inovance H3U Series - Page 304

303
4
4 Instructions 4.11.2 Verication
CRC: CRC code calculation
◆
Overview
A cyclic redundancy check (CRC) is a verication method used during communication. The CRC instruction
is used to calculate the CRC code.
CRC S n D
CRC code
calculation
Applicable model:
H3U
S
Source
data
Head address of elements that store the data for CRC
code calculation
16-bit instruction
(7 steps)
CRC: Continuous
execution
CRCP: Pulse
execution
n Data count Number of operated data entries (K1 to K256)
D Result Head address of elements that store the operation result
◆
Operands
Operand
Bit Element Word Element
System·User System·User Bit Designation Indexed Address Constant
Real
Number
S X Y M T C S SM D R T C SD KnX KnY KnM KnS KnSM
V,Z
Modication K H E
n X Y M T C S SM D R T C SD KnX KnY KnM KnS KnSM
V,Z
Modication K H E
D X Y M T C S SM D R T C SD KnX KnY KnM KnS KnSM
V,Z
Modication K H E
Note: The elements in gray background are supported.
◆
Function
16-bit conversion mode: When M8161 = OFF, the higher eight bits and lower eight bits (n data points in
total) from head address [S] are taken byte by byte for CRC code calculation. The result is stored in the
higher eight bits and lower eight bits from head address [D].
8-bit conversion mode: When M8161 = ON, the lower eight bits (n data points in total) from head address [S]
are taken byte by byte for CRC code calculation. The lower eight bits of the result are stored in [D], and the
higher eight bits are stored in [D+1].
An error is returned in the following condition. The error ag M8067 is set to ON to identify this error and
the error code is stored in D8067.
Error 6706 is returned when n is out of range.
◆
Application
M8161 = ON and the 8-bit conversion mode is enabled. The lower eight bits of elements D100 to D105 are
taken for CRC code calculation. The result is stored in the lower eight bits of D200 and D201.