Mitsubishi Electric MELSEC FX3U Programming Manual page 331

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
D
Before
execution
S+n
D
S+n
After
Word data is shifted.
execution
D
S+n
1) When the command input turns ON, the contents of
2) Accompanied by this transfer, the contents of the pointer
are shifted rightward by 1 word. (When the continuous operation type SFRD instruction is used, the
contents are stored in turn in each operation cycle. Use the pulse operation type SFRDP instruction in
programming.)
Related device
Device Name
M8020 Zero
Related instructions
Instruction
SFWR (FNC 38)
POP (FNC212)
Caution
1. Data after reading was executed
The contents of
2. In the case of continuous operation type (SFRD) instruction
Data is read in turn in each scan time (operation cycle), but the contents of
3. When pointer
Data is not processed, and the contents of
Program example
Refer to the program example provided for SFWR (FNC 38) instruction.
n
... S+10 S+9 S+8 S+7 S+6 S+5 S+4 S+3
S+n ... S+10 S+9 S+8 S+7 S+6 S+5 S+4 S+3
S+n S+n ... S+10 S+9 S+8 S+7 S+6 S+5 S+4 S+3
Word data is shifted.
Data is always read from
zero flag M8020 turns ON.
Shift write (for FIFO/FILO control)
Shift last data read (for FILO control)
+n do not change by reading.
S
is 0
S
11 Rotation and Shift Operation – FNC 30 to FNC 39
11.10 FNC 39 – SFRD / Shift Read [FIFO Control]
S+2 S+1
Pointer
Executed at the 1st time
S+1
S+2
Pointer
Executed at the 2nd time
S+2
Pointer
+1 are transferred (read) to
S
decrease, and the data on the left side
S
→ For the zero flag use method, refer to Subsection 6.5.2.
Description
+1. When the contents of the pointer
S
Description
do not change.
D
→ For the program example, refer to Section 11.9.
S S = n
−1 →
S S
S
−1 →
S S
S
.
D
become "0", the
S
+n do not change.
S
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