PLC help and sequencing

Hey, im at a stand still with one of my labs.

the lab consists of making a program to run similar to a washing machine. it includes, lights, motors, push buttons and selector switches.

One fellow classmate tried to do sequencing for the program. He had issues about resetting the program. It wouldn’t all reset at the same time.

We use ladder logic to program the PLC’s.

so i ask the great people at CD to help me out.

the lab goes as follows:

  • Wash the clothes for 3 minutes
  • spin the clothes for 30 seconds
    -rinse the clothes 3 minutes
  • final spin for 30 seconds
  • come to a stop

washing cycle includes:
-level selector (high, medium, and low level loads)
-water temperature (hot, warm, cold water)
-cold water is added during the spin cycle (3 times, 3 sec. each)
-lights to indicate which cycle the machine is in
-red light to indicate the whole cycle is done
-lights to indicate hot and cold water being added (separately)


What PLC and programming software are you using?

AB slick 150, ladder logic.

in this case, i would like to do it sequencing.

the issue at the moment is i can select cold wash, it does it thing and then when it’s over it resets back to the top of the program. then when i try to select warm water wash, it will not function. It will only stay on the cold wash cycle. It is not fully resetting the program so that i can select cold water wash, and then warm water wash once cold is done, and then some other kind of wash.

get what im saying?

straightens hat oakie dokie… I havent done this in a while (since i really really don’t like ladder logic) but i have a little experience with an Allen Bradley MicroLogix 1000.

I don’t remember the names of everything… but if you let a timer run for each one of your functions, then just tie the relay output for your motor or whatever to the EN channel out of the timer…

Well i may just be confusing but I believe thats what i did… I think that was almost two years ago now so i may be completely wrong.

Do you HAVE to use ladder logic?

Does anyone else wish you could program allen bradley PLCs with a sequential language? The hardware’s fantastic, its cheap (comparitvely), but man I can’t stand ladder logic. :o