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True/false status – Rockwell Automation 9323-PA1E QUICK START GUIDE APS 6.0 User Manual

Page 26

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Control Basics

2–9

The figure below shows a simple 1-rung ladder program. The rung includes two
input instructions and an output instruction. Note, in the example below each
instruction has a name (Examine if Closed), a mnemonic (XIC), and an address
(I:1/0).

A simple rung, using bit instructions.

XIC

( )

O:3

0

] [

I:1

0

]/[

I:1

1

XIO

OTE

Input Instructions

Output Instruction

XIC = Examine if Closed

XIO = Examine if Open

OTE = Output Energize

Address I:1/0

Address I:1/1

Address O:3/0

True/False Status

The data file bits that these instructions are addressed to will be either a logic 0
(OFF) or a logic 1 (ON). This determines whether the instruction is regarded as
“true” or “false”:

The status of the instruction is

If the data file

bit is

XIC

Examine if Closed

] [

XIO

Examine if Open

]/[

( )

OTE

Output Energize

Logic 0

False

True

False

Logic 1

True

False

True