The controller evaluates each element, or function block, in the network in a sequence that starts at the top left hand corner; or ROW 1, COLUMN 1.
The ladder evaluation moves down column 1 until it reaches row 8. The evaluation then continues at the top of column 2 and moves down to row 8 again.
This process continues until the entire network has been evaluated. If there is more than one network, evaluation continues to the next sequential network in the program until the entire program has been evaluated.
Refer below image:
The ladder evaluation moves down column 1 until it reaches row 8. The evaluation then continues at the top of column 2 and moves down to row 8 again.
This process continues until the entire network has been evaluated. If there is more than one network, evaluation continues to the next sequential network in the program until the entire program has been evaluated.
Refer below image: