PLC skills test

A two phase stepper motor controller and ten requirements respectively in 1 seconds, 0.5 seconds for the beat (button), control in the following order:, A - B - B - C - D - D - B - A - A...

Set the start button, stop button, start according to the above the beat output after running: set phase-locked select button, when selecting phase locked state, stops to keep the current state (state) when keep stop, press the start button again, before going on to stop running state: when not select lock button, after stopping is no output, after the restart, starting with A output (in 5 lamp simulation),