input image

A copy of every input, taken at the start of a scan. The logic reads this copy, so an input cannot change halfway through a scan, even if the real device does.

One scan: read all inputs, run the rungs from top to bottom, write all outputs, then start again.1Read inputsAll inputs,all at once2Run rungsTop to bottom,left to right3Write outputsAll outputs,all at onceThen again. The Scan setting (20 ms) sets how often.

Read more

Learn it in a lesson