i am a beginner plc programmer and have some confusion, a little help would be appreciated . why do we use a normally close contact when we are dealing with low pressure switch and use normally open contact when dealing with high pressure switch? i saw a programmer doing this while writing his program in ladder diagram and i got confused. should not it be that both the switches are normally close in both low and high and opens if the pressure drops down a certain level or increases above certain level?
thanks in advance
thanks in advance