ladder logic

There is really no way to answer your question. With a plc, the only limitation is your imagination. The style that some people use in ab is use the JSR instruction in file 2 to jump to the other files you create,Lad 3, Lad 4 etc..... With siemens, It would be a JU in OB1 to jump to other files Pb's, Fb's etc....

lad2.jpg
 
My 2 cents

When I am constructing ladder logic, I like to seperate the code into sections.
First: manual control,
Second: automatic control,
Third: logic taken from first and second step and other inputs,
Fourth: outputs to material handling from logic derived in 3rd step, Fifth drive outputs for lights

Although an e stop will remove power to all output rails via hard wired relays, I also use the e stop signal to prevent outputs from being generated.

Doing it this way seperates the program into logical steps. It is easier to follow and troubleshoot.

Thats my story and I'm sticking to it.
 
Well I'm new to the site so this just might not go over to well. But in my opion please dont use latch and unlatch for safety reasons. Alaways think of safety first. I personally have not wrote a lot of programs, only in school. But whatever problem that was given to me I never had a need for latches. It is retenitive. Sorry it's just my opion. Also my spelling could use some work.
 

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