Single button Start Stop latching logic

[ratanidol]

sir, can you explain.. how the exor gate formula you have applied here is working in the second rung

 

[iant]

sir, can you explain.. how the exor gate formula you have applied here is working in the second rung

There are thousands of posts for this function. Some will work with some Plcs but not all. This logic relies on the scan cycle of the PLC. It would not work with hard wiring.
Most of us on this site have always cryptically answered this question

About 100% of these are student related. You need to do the effort
This is a favorite training question of mine too

Sorry mate

Work it out

 

[Mihir_007]

Try CTU.
When even, output will be on and at odd output will be off.
single button to update counter.


As simple as "SIMPLE".

 

[duckman]

Hi Mihir, what do you use to see/move the even/odd in the count up

 

[TConnolly]

(Old thread alert)


He is refering to using the .ACC/0 bit of a counter. When the value of the ACC is odd bit .ACC/0 is set. When it is even the bit is clear. Its a simple way to make a retentive flip flop. (Counter never needs to be reset, ignore preset and .dn bits)

If you look at the accumulator value in binary
0 = 000
1 = 001
2 = 010
3 = 011
4 = 100
5 = 101
6 = 110
notice how each time the counter upcounts the least significant digit changes state.

So by programming a button to a counter and using

  Counter.ACC/0                Output

-------] [----------------------( )

you can have a simple retentive flip flop. If your flip flop should not be retentive then use the Oneshot and XOR logic posted earlier.