Rockwell-automation Logix5000 Controllers Structured Text Programming Instrukcja Użytkownika Pobierz pdf (Strona 18)

18 Publication 1756-PM007D-EN-P - November 2012

Chapter 1 Program Structured Text

Use Logical Operators

Logical operators let you check if multiple conditions are true or false. The

result of a logical operation is a BOOL value:

Use these logical operators:

For example:

If the comparison is The result is

True 1

False 0

For Use this operator Data Type

Logical AND &, AND BOOL

Logical OR OR BOOL

Logical exclusive OR XOR BOOL

Logical complement NOT BOOL

Use this format Example

For this situation You’d write

BOOLtag

If photoeye is a BOOL tag and your specification

says: “If photoeye_1 is on then…”

IF photoeye THEN...

NOT BOOLtag

If photoeye is a BOOL tag and your specification

says: “If photoeye is off then…”

IF NOT photoeye THEN...

expression1 & expression2

If photoeye is a BOOL tag, temp is a DINT tag,

and your specification says: “If photoeye is on

and temp is less than 100⋅ then…”.

IF photoeye & (temp<100) THEN...

expression1 OR expression2

If photoeye is a BOOL tag, temp is a DINT tag,

and your specification says: “If photoeye is on

or temp is less than 100⋅ then…”.

IF photoeye OR (temp<100) THEN...

expression1 XOR expression2

If photoeye1 and photoeye2 are BOOL tags and

your specification says: “If:

• photoeye1 is on while photoeye2 is off or

• photoeye1 is off while photoeye2 is on

then…"

IF photoeye1 XOR photoeye2 THEN...

BOOLtag := expression1 & expression2 If photoeye1 and photoeye2 are BOOL tags,

open is a BOOL tag, and your specification says:

“If photoeye1 and photoeye2 are both on, set

open to true”.

open := photoeye1 & photoeye2;

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