Rockwell Automation 1746-BAS BASIC LANGUAGE - Manual (Page 92)

Publication 1746-RM001A-US-P
7-8 Control Functions
If line 100 exists, this statement causes execution of the program to resume at line
100. If line number 100 does not exist, the message
ERROR: INVALID LINE
NUMBER
is printed to the console device and the module enters the Command
mode.
Unlike the RUN command, the GOTO statement, if executed in the Command
mode, does not clear the variable storage space or interrupts. However, if the
GOTO statement is executed in the Command mode after a line is edited, the
module clears the variable storage space and all BASIC evoked interrupts.
IF-THEN-ELSE Purpose
Use the IF-THEN-ELSE statement to set up a conditional test.
Syntax
IF [rel expr] THEN valid statement ELSE valid statement
Examples
Example 1
>1 REM EXAMPLE PROGRAM
>10 IF A =100 THEN A=0 ELSE A=A+1
Upon execution of line 10 IF A is equal to 100, THEN A is assigned a value of 0.
IF A does not equal 100, A is assigned a value of A+1. If you want to transfer
control to different line numbers using the IF statement, you may omit the GOTO
statement. The following examples give the same results:
>20 IF INT(A)<10 THEN GOTO 100 ELSE GOTO 200
or
>20 IF INT(A)<10 THEN 100 ELSE 200
You can replace the THEN statement with any valid module statement as shown
below:
>30 IF A<>10 THEN PRINT A ELSE 10
>30 IF A<>10 PRINT A ELSE 10