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746
Table Data Processing Instructions
Section 3-17
Description
SREAD(639) reads the data from the address specified by the stack pointer
(TB+3 and TB+2) minus the offset value in C. SREAD(639) does not change
the data in the stack or the stack pointer.
SREAD(639) can be used to read the data for an item currently on a conveyor.
The position of the desired item is simply the number of items back (the offset
value) from the most recent item added to the conveyor.
Flags
Precautions
The stack must be defined in advance with SSET(630).
The address in the stack pointer must be greater than the PLC memory
address of the beginning of the data region (TB+4). An error will occur if the
stack pointer is less than the PLC memory address of TB+4, i.e., if a stack
underflow error occurs.
Examples
When CIO 000000 is ON in the following example, SREAD(639) reads the
data in the specified word in the stack starting at D00000 and outputs the data
to D00100. In this case, the stack pointer indicates D00007 and the offset
value is 3, so the data is read from D00004.
Index Registers
---
Indirect addressing
using Index Registers
,IR0 to ,IR15
–2048 to +2047 ,IR0 to –2048 to +2047 ,IR15
DR0 to DR15, IR0 to IR15
,IR0+(++) to ,IR15+(++)
,–(– –)IR0 to, –(– –)IR15
Area
TB
C
D
A
A
B
C
TB
TB+1
TB+2
TB+3
TB+4
D
m
n
C
n
m
PLC memory
address
Pointer
Reads the data (A) in the specified
word and outputs that data to D.
The address of the desired word is
calculated by subtracting the offset
value from the stack pointer address.
Last word
in stack
Stack
Offset value
Reads the data (A) without
changing the stack pointer.
The data (A) is
not changed.
Name
Label
Operation
Error Flag
ER
ON if the specified read location is not within the stack
area.
ON if the offset value specified in C is 0 or greater than
the maximum data region size (FFFB hex).
OFF in all other cases.
Equals Flag
=
ON if the output data in D is 0000.
OFF in all other cases.
Summary of Contents for SYSMAC CS Series
Page 2: ......
Page 4: ...iv ...
Page 30: ...xxx ...
Page 186: ...146 List of Instructions by Function Code Section 2 4 ...
Page 1320: ...1280 Model Conversion Instructions Unit Ver 3 0 or Later Section 3 35 ...
Page 1390: ...1350 CJ series Instruction Execution Times and Number of Steps Section 4 2 ...
Page 1391: ...1351 Appendix A ASCII Code Table ASCII SP Four leftmost bits Four rightmost bits ...
Page 1392: ...1352 ASCII Code Table Appendix A ...
Page 1404: ...1364 Revision History ...