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Refer to 6-1 Cycle Time for a table showing I/O refresh times for Group-2
High-density I/O Units.
Flags ER: St or E is not BCD between #0000 and #000F.
St is greater than E.
5-25-10 BIT COUNTER – BCNT(67)
N: Number of words (BCD)
IR, SR, AR, DM, HR, TC, LR, #
SB: Source beginning word
IR, SR, AR, DM, HR, TC, LR
Operand Data Areas
D: Destination word
IR, SR, AR, DM, HR, TC, LR
Ladder Symbols
BCNT(67)
N
SB
D
@BCNT(67)
N
SB
D
Limitations N must be BCD between 0000 and 6656.
Description When the execution condition is OFF, BCNT(67) is not executed. When the
execution condition is ON, BCNT(67) counts the total number of bits that are ON
in all words between SB and SB+(N–1) and places the BCD result in D.
Flags ER: N is not BCD, or N is 0; SB and SB+(N–1) are not in the same area.
The resulting count value exceeds 9999.
Indirectly addressed DM word is non-existent. (Content of DM word is
not BCD, or the DM area boundary has been exceeded.)
ON when the count (N) exceeds the data area boundary.
EQ: ON when the result is 0.
5-25-11 FRAME CHECKSUM – FCS(––)
C: Control data
IR, SR, AR, DM, HR, LR, #
R
1
: First word in range
IR, SR, AR, DM, HR, TC, LR
Ladder Symbols
Operand Data Areas
D: First destination word
IR, SR, AR, DM, HR, LR
FCS(––)
C
R
1
D
@FCS(––)
C
R
1
D
Description FCS(––) can be used to check for errors when transferring data through commu-
nications ports.
When the execution condition is OFF, FCS(––) is not executed. When the
execution condition is ON, FCS(––) calculates the frame checksum of the speci-
fied range by exclusively ORing either the contents of words R
1
to R
1
+N–1 or the
bytes in words R
1
to R
1
+N–1. The frame checksum value (hexadecimal) is then
converted to ASCII and output to the destination words (D and D+1).
Special Instructions Section 5-25