Question: Devise ladder programs for systems that will carry out the following tasks:
(a) Give an output after a photocell sensor has given 10 pulse input signals as a result of detecting 10 objects passing in front of it.
(b) Give an output when the number of people in a store reaches 100, there continually being people entering and leaving the store.
(c) Show a red light when the count is less than 5 and a green light when it is equal to or greater than 5.
(d) Count 10 objects passing along a conveyor belt and close a deflecting gate when that number have been deflected into a chute, allowing a time of 5 s between the tenth object being counted and closing the deflector.
(e) Determine the number of items on a conveyor belt at any particular time by counting those moving onto the belt and those leaving and give an output signal when the number on the belt reaches 100.