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7.21
Module access instruction
I/O refresh
REF(P)/RFS(P)
These instructions refresh the (n) points of devices starting from the device specified by (s), and receive an external input or
generate an output.
The REF(P) instructions can also be used as RFS(P).
Ladder diagram
(s)
(n)
Setting data
■Descriptions, ranges, and data types
Operand
Description
(s)
Head device number to be refreshed
(n)
Number of devices to be refreshed
■Applicable devices
Operand
Bit
X, Y, M, L,
U\G T, ST,
SM, F, B, SB
*1
(s)
(n)
*1 Only X and Y can be used.
Processing details
• This function refreshes only the corresponding devices in the middle of a scan and receives an external input or generates
an output.
• Since the input receptions and external outputs are performed at one time only after the END instruction is executed in the
program, a pulse signal cannot be output externally in the middle of a scan. The execution of the I/O refresh instruction
forcibly refreshes the corresponding input (X) or output (Y) in the middle of program execution, and then a pulse signal can
be output externally in the middle of a scan.
• To refresh an input (X) or an output (Y) in 1 point units, use the direct access input (DX) or the direct access output (DY).
[Program based on the REF instruction]
Command
REF
X0
Command
REF
[Program based on direct access input and direct access output]
DX0
Direct access input
Structured text
ENO:=REF(EN,s,n);
ENO:=REFP(EN,s,n);
Range
0 to 65535
Word
T, ST, C, D,
U\G
C, LC
W, SD, SW, R
Refreshes X0.
X0
K1
Y20
Refreshes Y20.
K1
Y20
DY20
Direct access output
Data type
Bit
16-bit unsigned binary
Double word Indirect
specification
Z
LC
LZ
7 APPLICATION INSTRUCTION
7.21 Module access instruction
Data type (label)
Bit
ANY16
Constant
Others
K, H
E
$
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