Vigor VS Series User Manual

164
S F R D P
D
n
S
1
2
M
3
○ ○ ○○
FNC
39
n
X Y M S
D.b R.b
KnX KnY
KnM KnS
T C
D,R
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K,H
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S
D
S : the header ID number of the FIFO data stack
D : the destination device for storing read data from
a FIFO data stack
n : the length of the FIFO data stack
SFRDP D0 D101 K10
X21
S
D
n
S
n
D
Operand
Devices
Shift Register Read (FIFO Read)
S occupies n components
n = 2~512
D101
D9 D8
D7
D6 D5
D4
D3
D2 D1
D0
Subtracts “1” from the content
value of the indicator D0
3
Batch shift by one word position
to the right
2
Read data
1
Indicator
The FIFO data stack is composed by
D0~ D9, where the D0 is the indicator
A series of word data can be used for the FIFO (First In, First Out) data stack access. The FIFO data stack is
headed by , the size is assigned by and the stack's rst device is designated to be the indicator. When
each time this instruction is enabled, it moves the content value of the second device in the FIFO data stack to the
destination device rstly, then the rest data in the stack (without the moved out device and the indicator) will be
shifted one word position to the right, furthermore subtracts “1” from the indicator’s content value.
Suppose at the very beginning that D0 = 5. At the rst time X21 = “OFF” → “ON”, the content value of D1 will be
moved to the D101 then the content values at D2~D9 will be shifted one word position to the D1~D8 also the content
value of D0 will subtract “1” become “4”. At the second time X21 = “OFF” → “ON”, again the content value of D1
will be moved to the D101 then the content values at D2~D9 will be shifted one word position to D1~D8 also the
content value of D0 will become “3”, and so forth.
When the content value of D0 is equal to “0” and the instruction is active again, it will not execute to read data,
decrease the indicator or shift process any more. So the value of (D101) will remain the previous value, and furthermore
the Zero Flag M9020 = “ON”.
This SFRD instruction is usually used jointly with the SFWR instruction (refer to the previous page) to achieve the
write / read control of the FIFO data stack.
The source device is
designated by
D
Length is designated by
n

Vigor VS Series Specifications

General

Brand	Vigor
Model	VS Series
Category	Controller
Language	English