What's wrong with Siemens plc after seeing the functional diagram? The kind-hearted elder brother and elder sister knew how to tell the younger brother about it. I'm very grateful.

ld introduces normally open ldi introduces normally closed and series normally open ani series normally closed or parallel normally open ori parallel normally closed anb circuit block series orb circuit block parallel mps into the stack mrd read the stack mpp pop these are Commonly used input instructions according to the drawing or directly draw the ladder diagram