1057
Model Conversion Instructions Section 3-33
FIFO Stack Read Operation (Of = 9000 to 9999 BCD)
If the leftmost digit of Of is 9, COLLC(567) will operate as a FIFO stack
instruction (FIFO stands for First-In-First-Out). In this case, the rightmost 3
digits of Of specify the size of the stack.
COLLC(567) copies the data from the oldest word recorded in the stack to D.
The source word is Bs + 1. After the data is copied, the stack pointer is decre-
mented by 1.
Note Use DISTC(566) to write stack data to the stack area.
Flags
Note In C-series PLCs, the DATA COLLECT (COLL) instruction will cause the Error
Flag to go ON if the content of an indirectly addressed DM word (*DM) is not
BCD, or the DM area boundary is exceeded. COLLC(567) will not cause the
Error Flag to go ON in these cases.
Precautions Once DISTC(566) has been executed with Stack Push Operation to allocate a
stack area, always specify that same length stack area in the COLLC(567)
instructions. Operation will be unreliable if a different stack area size is speci-
fied in the COLLC(567) instructions.
Be sure that the offset or stack size specified by Of does not exceed the end
of the data area when added to Bs.
The offset data in Of must be BCD.
D
OfBs
Bs+1
Stack area
Stack
pointer
Stack
data area
m words
Size of
stack are
9
m
S1+
Data is copied from
Bs + 1.
Name Label Operation
Error Flag ER ON if the offset data in Of is not BCD.
ON if LIFO or FIFO Stack Operation is specified, but the
stack pointer data in Bs is not BCD.
ON if LIFO or FIFO Stack Operation is specified and the
stack pointer indicates a word that exceeds the stack data
area.
OFF in all other cases.
Equals Flag = ON if the source data is 0000.
OFF in all other cases.
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