controlling water level in a tank

I am trying to build a project for controlling water level in a tank using PLC,3 level sensor, water pump, and electrical valve and i need help any one teach me how i can build up my project and i am willing to pay for the help

Edit: Start by making a sketch of where the various components will be in relation to the tank...

Then continue by writing yourself a specification of how you want it to work.

First part of the spec. will be whether you want the tank level control to be completely autonomous, or do you want it to be started and stopped, in which case you will need some sort of "Operator Interface" - which could of course just be some push-buttons and lamps.

Then write the spec. for the sequence of filling a tank... keep each statement simple, e.g.

If Low-level probe is uncovered, open valve X to fill tank.

etc.

Coding from a well-written description of the process is easier than deciding the process on larger systems.

Ali, i had a problem with a tank that kept overflowing that had mechanical floats. Not good. Rust, and contaminents in the water was always causing problems. I found a capacitive proximity switch from MSC company, normally open, and installed it to verify the water level of the tank. When the water level got below the prox, it would turn on a valve to fill. I programmed a timer so that it would fill for 30 seconds, then shut off. 300 gallon tank, yours may be different. I programmed a timer, keep it on for 30 seconds, then shut off. If not filled, then another 20 seconds, so on so forth. This prox worked great and has been in use for about 2 years. Also, it is grease proof, only liquid will activate it. MSC part number 54049762 @ $221. Well worth it. Check it out

Tony

tell us what you did, show us your homework in a sketch and a ladderdiagram.

Another concern to be aware of .......... You should limit the number of cycles that the pump makes.
Starting and stopping a pump is the worst case for the motor, high current on starts and heat soak on stops.

You were not specific about your level sensor,if you are using for example an ultrasonic sensor, scale your analog input to reflect the values of your sensor in relation to tank capacity and use high and low limits to control operation of your valve or pump. I am attaching a ladder diagram which is using a sensor for level control; the scenario is different in that it is using a floodgate as opposed to a valve or pump but the logic is similar and should give you some insight.