Mitsubishi Electronics FX3G User Manual

314

/FX

3GC

/FX

3UC

Series

Programming Manual - Basic & Applied Instruction Edition

11 Rotation and Shift Operation – FNC 30 to FNC 39

11.10 FNC 39 – SFRD / Shift Read [FIFO Control]

1) When the command input turns ON, the contents of

+1 are transferred (read) to

2) Accompanied by this transfer, the contents of the pointer

decrease, and the data on the left side 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

→ For the zero flag use method, refer to Subsection 6.5.2.

Related instructions

Caution

1. Data after reading was executed

The contents of

+n do not change by reading.

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

+n do not change.

3. When pointer

is 0

Data is not processed, and the contents of

do not change.

Program example

Refer to the program example provided for SFWR (FNC 38) instruction.

→ For the program example, refer to Section 11.9.

Device

Name

Description

M8020

Zero

Data is always read from

+1. When the contents of the pointer

become "0", the zero flag

M8020 turns ON.

Instruction

Description

SFWR (FNC 38)

Shift write (for FIFO/FILO control)

POP (FNC212)

Shift last data read (for FILO control)

S+n

...

S+2

S+10 S+9 S+8 S+7 S+6 S+5 S+4 S+3

S+1

S+n

...

S+2

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

−1 →

Executed at the 2nd time

Executed at the 1st time

S+2

Word data is shifted.

S+1

= n

Pointer

Before

execution

After

execution

−1 →