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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 #0009.
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 exe-
cution 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 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.)
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 ex-
ecution 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