There are a lot of programming options for PLCs these days. Learning the software is not that difficult for anyone who understands relay logic. Some companies such as Horner Electric ("www.heapg.com":http://www.heapg.com ) even offer their software for free (Cscape v5.01), just download it from their web site.
More complex software is also available for those who want to program in SFC, State Logic, C++, and Function Diagram.
Level detection can be digital (ON/OFF signal) if you choose something like a float switch; or it can be an analog (time varying) signal from many different types of level transmitters. You need to read the correct type of signal in an adequate range for your chosen PLC, and program a valid response from your system (open/close valves, start/stop pumps...). But you must start by
understanding the process and the controler.
You may want to check out the website "plcs.net":http://www.plcs.net . This site contains detail tutorial info (and is animated for some tutorials) that should get you well on your way.
You may want to check out the website "plcs.net":http://www.plcs.net . This site contains detail tutorial info (and is animated for some tutorials) that should get you well on your way.