ELSE statements

Oftentimes, we’ll need a default block of code to run if the IF statement does not evaluate to TRUE. To accomplish this, the ELSE statement is employed. The ELSE statement is like a catcher in a baseball game. If the batter misses the ball, it’s the catcher’s job to catch the ball and throw it back to the pitcher. Consider the following example:

If motor1 = selected then
     turn on motor1
     turn off motor2
Else
     turn on motor2
     turn off motor1

For this example, if motor1 is selected, that motor will turn on. If motor1 is not selected, then motor2 will turn on. Again, the ELSE block is like the catcher; if motor1 is not selected, it will catch that and turn on motor2. To see this in action, implement the following variables:

PROGRAM PLC_PRG
VAR
     selectMotor1       ...