1 input 3 outputs

[Lancie1]

guest,

Of course you can do what you described. Steve, he did say to:
"...make one input turn on 3 outputs one at a time?
Leave one on until the next one is turned on.
Do this without using osr or counter or timer."

And his answer is very close:
"If First Scan - Set FirstScan
If Input and Output 3 or FirstScan - Set Output 1, Reset Output 3, Reset FisrtScan
If Input and Output 1 - Set Output 2, Reset Output 1
If Input and Output 2 - Set Output 3, Reset Output 2"

If I were doing it, I would forget the First Scan bit. Your original instructions say nothing about a first scan being a condition, but only that the Input is a condition. So here is my solution:

"If Input and Output 3 or INPUT AND NOT OUTPUT 1 AND NOT OUTPUT 2 AND NOT OUTPUT 3, then - Set Output 1, Reset Output 3
If Input and Output 1 - Set Output 2, Reset Output 1
If Input and Output 2 - Set Output 3, Reset Output 2"

The above will always start with Output 1, anytime that Input is ON, and progress to Output 3, and then recycle. However, as has been pointed out by rdrast and others, the circuit will run through the logic and switch one output on each PLC scan, so the outputs will switch so fast that you probably will only see an erratic blink (if you watch the LED output indicators) every now and then, even though the logic is working correctly. In other words, it works logically, but has little practical application in the real world. Humans unfortunately cannot see and think as fast as the PLC. I wish I had a dime for every ladder routine that I have erroneously written like this one! To make it into something useful, you need another variable, such as a timer or another input, to control HOW LONG that each output is ON.

 

[Tim]

Originally posted by Lancie1
he did say to:
"...make one input turn on 3 outputs one at a time?
Leave one on until the next one is turned on.
Do this without using osr or counter or timer."

He, "Guest" did restate his question. His original was a little confusing, but if you look at his other reply he states what he's actually after.

guest, forget about those SET,.. RESET, relays. USE INTERNAL RELAYS!!!
beerchug
Tim

 

[anotherguest]

Will this work?

  input          start over                             first time on

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

 |              |

 |first time on |

 |----[]--------|



  first time on    input                               first time off

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

                 |              |

                 |first time off|

                 |----[]--------|



  first time off    input                               second time on

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

                 |              |

                 |second time on|

                 |----[]--------|



  second time on    input                              second time off

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

                 |               |

                 |second time off|

                 |----[]---------|



  second time off  input                                 third time on

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

                 |              |

                 |third time on |

                 |----[]--------|



  third time on    input                                third time off

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

                 |              |

                 |third time off|

                 |----[]--------|



  third time off    input                                   start over

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

                



  first time on    second time on                              output1

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





  second time on    third time on                              output2

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





  third time on                                                output3

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

 

[panic mode]

I'll admit, I already got itch to post some code but anotherguest was faster...

beerchug

 

[msinclair]

Since a couple of solutions are already posted (including some work from "guest"), here's a quick way to do what you want in an AB PLC.

For our guest learner, it shows a roll-your-own one-shot, and the importance of sequencing your instructions properly.

Replace B3:0/0 with "Input"
Replace B3:0/13 with "Output 1"
Replace B3:0/14 with "Output 2"
Replace B3:0/15 with "Output 3"

B3:0/1 and B3:0/2 are used for the roll-your-own one-shot.

Marc

 

[dandrade]

IS EASY Sometime two lines work main.

-----------|   |-----------------------------[ADD D1 K1 D1]   It acumalator  

---------| NF |-------------------------------[MOV D1 Y1]

Operation mathematics=> + - * / , it determine sequence

It aplieed, for control motors, softstarte, sequence ativation, selections, ....

If necessary the limitation output use mask and reset move ZERO to
variable.


To more SMALL impossible!!!

Good thinks

 

[anotherguest]

How about this for AB?

  output 1   output2                                       test bit

---[/]---------[/]------------------------------------------(B0)------



   input                                             BSL

---[]----------------------------------------------|               |--

                                                   |File     #B3:1 |

                                                   |Control   R6:0 |

                                                   |Bit Addr  B0   |

                                                   |Length     3   |

                                                   -----------------



 first bit    second bit                                   output 1

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



 second bit    third bit                                   output 2

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



 third bit                                                 output 3

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

 

[JVPSUK]

I aggree with Bill, guests problem could have been solved using only relay logic, if everyone accepts that statement then simple logic gates (and, nand, or, nor) can solve the problem. I will not give the guest his answer right away, he should ponder a bit, but if he thinks in terms of his single input triggering o/p 'A', use a self hold circuit for 'A' along with inverted input, now you have a new set of conditions the next time the input goes high - o/p 'B' goes high, o/p 'A' goes low, think along those lines "guest". A PLC is just what it says, a logic controller. Jim.

 

[Platootod]

Step by step or impulse switch

Dear guest student
My answer is not PLC control but with control relay.
(I Hope all plcs's guy here are not mind)
Step by step or impulse switch can solve your problem.
If you learn RelaY DIAGRAM (Step by step or impulse switch )CIRCUIT
you can solve this problem very easy. Eventhough you have more than
10 ,30,50 steps ..only one input to control many output without timers , counter .. but a lot of control relays you need ..( The answer is yes ..you can do it but
non sense to pay for that ..)
Do you want to see example ?
If you need , I will post some picture for guide you next time

Platootod
Mechatronics RIT.Nonthaburi Campus

 

[Platootod]

An Example but not answer

Dear friends,
I post some example picture for you ,but this is not the answer
only a guide for this question
This circuit was simulate by the constructor software from
www.koldwater.com
When press Sw . S2 first time C1 will on
When press Sw . S2 second time C2 will on
When press Sw . S2 third time C3 will on
When press Sw . S2 forth time C4 will on (C4 not bomb ha ha)
I hope "guest " can apply to his question as well.

Platootod
Mechatronics Rit.Nonthaburi

 

[Platootod]

When press Sw S2 (fifth) c1 to c4 off

Dear "guest"
You can observe the circuit and change the condition depend on your's process.
If you need more step and the contact of a1(control relay) not enought just add more a1 no.2 , a1 no.3 ...etc parrallel with a1 no.1

Sawasdee Krub

Platootod

 

[Sleepy Wombat]

And here's another way......