Stack Data Read: Sread(639) - Omron SYSMAC CJ - REFERENCE MANUAL 08-2008 Reference Manual

Programmable controllers

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Table Data Processing Instructions

3-17-15 STACK DATA READ: SREAD(639)

Ladder Symbol

Applicable Program Areas

The stack must be defined in advance with SSET(630).

When CIO 000000 is ON in the following example, SNUM(638) counts the

number of words from the beginning of the data region at D00004 to the stack

pointer position - 1 (D00006) and outputs the result to D00300. (In this case,

the stack pointer indicates D00007.)

PLC memory address of

last word in the stack

Stack pointer

Reads the data from the specified data element in the stack. The offset value

indicates the location of the desired data element (how many data elements

before the current pointer position).

This instruction is supported by CS1-H, CJ1-H, CJ1M, and CS1D CPU Units

Executed Each Cycle for ON Condition

Executed Once for Upward Differentiation

Executed Once for Downward Differentiation Not supported.

Immediate Refreshing Specification

Block program areas

TB through TB+3: Stack control words

The first four words of the stack contain the PLC memory address of the last

word in the stack and the stack pointer (the PLC memory address of the next

available word in the stack.)

Counts number of data

words. (3 in this example.)

TB: First stack address

C: Offset value

D: Destination word

Step program areas

Section 3-17

Not supported.

Interrupt tasks

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