programming a button

[florin1626]

Hello guys! I need some help and i hope that someone will be able to solve this little problem. I wan't to make in Step 7, ladder diagram a button and when i press this button a led turns on and when i press again this button the led should turn off. Please give some help

 

[L D[AR2P#0.0]]

Which CPU
What input adddress for button
What output address for LED
Which Version of Simatic manager are you using.

 

[chavak]

http://www.plctalk.net/qanda/search.php?searchid=1892850

 

[KalleOlsen]

This was really a hard nut, but here is my solution:

 

[KalleOlsen]

With this variant you will have to push 32767 times to get the lamp on, and 32768 times to switch it off again. PS! Not tested!

 

[florin1626]

i tried this solutions that were posted but it's not a correct solutions. So i press the button the led turns on and when i release the button the led should still be on. Only after i press again the button the led should turn off.

 

[dmroeder]

http://www.plctalk.net/qanda/search.php?searchid=1892850

See chavak's link. The term for the circuit you are looking for is Flip-Flop and is the most commonly asked about topic in the forum.

 

[dmroeder]

http://www.plcs.net/chapters/oneshot18.htm

This is from the help on this site.

 

[florin1626]

thanks a lot. has anyone a good book with examples and maybe some explanations? i would appreciate a lot and also give a beer.

 

[florin1626]

I forgot to mention that i need a book about Simatic S7-300.

 

[florin1626]

i can't find the function DIFU in Step 7. Maybe it's another block with some functions like DIFU.

 

[dmroeder]

DIFU in that sample is a one-shot instruction.