PLC programming

We have the following Inputs/outputs:

Start(S1), Stop(S2), Level indicator(S4), Low level(B3), high level (B2), Indication lamp(H1) and a pump("PUMPE").

The function of the system is that there is a tank of water and the level has to be between B2 and B3. When the water is above B2 the pump has to start and keep going until the water is below B3. The pump should not start before the level is above B2 again. H1 is on as long as the facility is operational. We alredy have the program, but with some blanks that have to be filled in using the boxes in the picture at the end. The blanks are shown with [ ].

Program

If [ ] Then // if S4 is on, stop pump, turn off H1

[ ]

[ ]

Else

If [ ] Then //if S1 is on, turn on H1 and decide when pump should be on/off

[ ]

[ ] And Not [ ]// detection B2

[ ]

If [ ] Then //if B2 is detected, start pump

[ ]

End_if;

ElsIf [ ] Then // if S2 is on, stop pump and turn off H1

[ ]

[ ]

End_if;

End_if;

H1 = FALSE