739
Table Data Processing Instructions Section 3-17
Ladder Symbol
Variations
Applicable Program Areas
Operands C and C+1: Control words
C specifies the number of units (bytes or words) to be used in the FCS calcu-
lation. (Bit 13 of C+1 determines whether bytes or words are being used.)
When bit 13 of C+1 has been set to 1, FCS(180) calculates the FCS value for
bytes of data. In this case, bit 12 determines whether the calculation starts
with the rightmost byte of R1 (bit 12 = 1) or the leftmost byte of R1 (bit 12 = 0).
Note C and C+1 must be in the same data area.
R1: First word in range
R1 specifies the first word in the range. The length of the range depends on
the number of units as well as the starting byte, if bytes are being used in the
calculation.
Note All of the words in the calculation range must be in the same data area.
FCS(180)
C
R1
D
C: First control word
R1: First word in range
D: First destination word
Variations Executed Each Cycle for ON Condition FCS(180)
Executed Once for Upward Differentiation @FCS(180)
Executed Once for Downward Differentiation Not supported.
Immediate Refreshing Specification Not supported.
Block program areas Step program areas Subroutines Interrupt tasks
OK OK OK OK
15 0
C
15 014
0
C+1
13 12 11
0000 0000 000000
0
Calculation units
Number of words/bytes in range
Starting byte (Valid only when bit 13 is 1.)
0: Leftmost byte
1: Rightmost byte
0: Words
1: Bytes
R1
15 0
R1+(C units–1)
to
to
Calculation range
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