Newbie in the field of Automation here! I have a waste water project that requires operating 6 pumps to empty a sump. The water level in the sump is being monitored by an analog ultrasonic sensor. The analog range is divided into 5 levels; level 1 being the lowest and level 5 being the highest. The way the pumps operate is analogous to the water level, i.e., 5 pumps will run at level 5, 4 pumps will run at level 4, 3 at level 3, 2 at level 2, and only 1 pump will run at level 1. The sixth pump is used to run the pumps sequentially and that's where I need help. Basically, the pumps can not be assigned to a certain water level as this would result in the pumps at the lower level run way more as compared to the pumps assigned to higher levels. The pumps need to alternate so as to keep the running hours of each comparable. Another requirement is that say if pump 1 turns on due to water level rise and then turns off due to water level fall, and again if the water level rises, then the next pump should start instead of pump 1, and so on for the rest of the pumps. Also, if one pump goes on some kind of fault, the 6th pump comes in and runs in its stead until the fault is reset. I'm trying to come up with a ladder program to make all this happen but hoped that I could find some help online. I feel like this is a common project and there should be someone that can give me the proper solution. With thanks, Aafaq.