User`s manual

GFK-1742A 11-1

Local Logic Tutorial

Introduction

The Local Logic programming language supports assignment, conditional statements, arithmetic,

logical, and relational operations. The Local Logic program runs synchronously with the motion

module position loop and as such is deterministic. The language includes constructs that allow the

Local Logic program to communicate information between the Logic program, the Motion

Program, and the host PLC. The tutorial focuses on the local logic language and its communication

with motion programs. The user should consult the chapter 7 for additional information concerning

the motion programmer language.

Statements

The Local Logic programming language supports assignment and conditional statements.

Assignment statements permit arithmetic results and bitwise logical operations to be assigned to a

variable. Conditional statements permit conditional local logic code execution. Conditional

execution is based on the value of a constant or variable, or the result of a relational or bitwise

logical expression.

Assignment statements use the “:=” operator. The following example multiplies two parameter

registers and assigns the result to another parameter register.

P001 := P210 * P107;

Note: Assignment statements require a semi-colon terminator as shown above.

Conditional statements use the IF-THEN-END_IF keyword combination. The END_IF keyword

concludes the conditional statement. The following example checks the Block_1 variables value

and conditionally sets a value in a parameter register. Specifically, if the Block_1 variable’s value

equals 5 then the parameter P010 value is set to 100.

IF Block_1 = 5 THEN

P010 := 100;

END_IF;

The IF, THEN, and END_IF keywords are case sensitive, and the END_IF statement is terminated

with a semi-colon. IF statements may be nested up to eight levels and the body of the IF statements

may contain one or more statements. Refer to Chapter 12 for a detailed description of these

statements.

Chapter