a.A cylinder moves from position "rear" [E1] to position "front" [E2] and vice versa
b.Pressing the key [E3] triggers the movement
c.If the cylinder is at E1 when the key is pressed, the cylinder moves to E2 If the cylinder is at E2 when the key is pressed, the cylinder moves to E1
d.The movement E1 to E2 is controlled by the valve "Cylinder Forward" [A1].
e.The movement E2 to E1 is controlled by the valve "Cylinder Back" [A2]