Help with Program

ameuba10 · Sep 25, 2008

im new to PLC's and i need help writing this program for my PLC's class. the teacher hasnt explained anything so any help will be great. this is the part im stuck on.

4. When lights 1 and 2 are turned on Y1 will be on and remain on after either light 1 or two are turned off. The only way to turn Y1 off after it is on is to turn light 3 on. If light 3 is on and light 1 and 2 are on Y1 will be on.

Reverse
4. When lights 1 and 2 are turned on Y1 will be off and remain off until light 3 is turned on. Y1 will remain on after light 3 is turned off as long as lights 1 and 2 are on.

The "Y's" are the outputs, and the "lights" are actually buttons.

im not some kid wanting my homework done for me. my teacher handed us all our work and expected that we knew how to do it. all i know is examine on and examine off. thanks

tragically1969 · Sep 25, 2008

ameuba10 said:
im new to PLC's and i need help writing this program for my PLC's class. the teacher hasnt explained anything so any help will be great. this is the part im stuck on.

4. When lights 1 and 2 are turned on Y1 will be on and remain on after either light 1 or two are turned off. The only way to turn Y1 off after it is on is to turn light 3 on. If light 3 is on and light 1 and 2 are on Y1 will be on.

Reverse
4. When lights 1 and 2 are turned on Y1 will be off and remain off until light 3 is turned on. Y1 will remain on after light 3 is turned off as long as lights 1 and 2 are on.

The "Y's" are the outputs, and the "lights" are actually buttons.

im not some kid wanting my homework done for me. my teacher handed us all our work and expected that we knew how to do it. all i know is examine on and examine off. thanks

Use the search button, there is heaps of these sort of questions on this forum, its generally accepted that you wont get any help of folk without first helping yourself by posting what you have figured out so far.

ameuba10 · Sep 25, 2008

see thats what i was afraid of. im on many other forums and when a poor newbie comes up with a dumb question everyone tell them to try the search button. but see i dont even know what to search. im so completely lost. the only thing i know is examine on and examine off. seriously the guy handed us all these projects and just said make sure theyre done by the end of the semester. i dont even know where to begin.

rdrast · Sep 25, 2008

ameuba10 said:
see thats what i was afraid of. im on many other forums and when a poor newbie comes up with a dumb question everyone tell them to try the search button. but see i dont even know what to search. im so completely lost. the only thing i know is examine on and examine off. seriously the guy handed us all these projects and just said make sure theyre done by the end of the semester. i dont even know where to begin.

No, it's just that most forums do not do homework assignments.
We will assist, as long as some effort is being made, but will not just hand over an answer.

That being said, why not start by clearing up the text... If 'lights' are 'switches' and 'Ys' are 'outputs', then your first step should be to list your actual input and output devices available.

Once that is done, use a piece of paper, and a pencil, and try to work out the logic of what should happen in response to a given set of inputs.

Hint: You probably want to search on 'Seal In' circuits.

mvandyke · Sep 25, 2008

Maybe this will help.
http://forums.mrplc.com/index.php?showtopic=8979&hl=light+3

ameuba10 · Sep 25, 2008

thanks guys. well my inputs are just basic buttons, and outputs are some lights. push a combo of buttons, then certain lights come on based on the program. X's=buttons Y's=lights. idk why my teach typed that up the way he did. but when he says lights, he means X's.

what i have so far is X1 and X2 examine on will make Y1 examine on true. im confused on how exactly to make it latch. im thinking putting a Y1 examine on in parallel with it? i really dont want to come off as a lazy kid who wants someone to do their homework for them, but i seriously dont have a clue on what to do here. thanks for the link.

dmkar · Sep 25, 2008

Make a logic-table with all inputs/outputs. It will help a lot.

tragically1969 · Sep 25, 2008

ameuba10 said:
thanks guys. well my inputs are just basic buttons, and outputs are some lights. push a combo of buttons, then certain lights come on based on the program. X's=buttons Y's=lights. idk why my teach typed that up the way he did. but when he says lights, he means X's.

what i have so far is X1 and X2 examine on will make Y1 examine on true. im confused on how exactly to make it latch. im thinking putting a Y1 examine on in parallel with it? i really dont want to come off as a lazy kid who wants someone to do their homework for them, but i seriously dont have a clue on what to do here. thanks for the link.

You have had the starting point given to you, list all inputs and outputs and transpose them over to a truth table on a piece of paper so you know what should be on and off at any one point etc

when you have done that start to think about how you are going to write the ladder

a latch works like this in its simplest terms:

X0 X1 Y0
--| |---|\|--------[ ]--
|
Y0 |
--| |-|

XO turns YO on which latches XO in, X1 turns it off.

milldrone · Sep 25, 2008

ameuba10 said:
The only way to turn Y1 off after it is on is to turn light 3 on. If light 3 is on and light 1 and 2 are on Y1 will be on.

This appears to conflict.

randyk · Sep 25, 2008

4. When inputs 1 and 2 are turned on output Y1 will be on and remain on after either input 1 or two are turned off. The only way to turn output Y1 off after it is on is to turn input 3 on. If input 3 is on and inputs 1 and 2 are on Y1 will be on.

Reverse
4. When inputs 1 and 2 are turned on output Y1 will be off and remain off until input 3 is turned on. Output Y1 will remain on after input 3 is turned off as long as inputs 1 and 2 are on.

If you change it to read the correct way it makes more sense. It sounds like a latched output. Input 3 would then be the unlatch, although the last line does sound kind of hoakie. If inputs 1 and 2 are on when 3 is triggered then Y1 would turn off, but then come right back on.

LJBMatt · Sep 25, 2008

This appears to conflict.

__________________
Vaughn

Yes and No. It is really just stating the fact that if light 1 and 2 being "ON" will turn on Y1 no matter the state of light 3. In essences if light 1 and 2 are "ON" the state of light 3 is a "Don't Care" as it could either be "ON" or "OFF".

LJBMatt · Sep 25, 2008

randyk said:
4. When inputs 1 and 2 are turned on output Y1 will be on and remain on after either input 1 or two are turned off. The only way to turn output Y1 off after it is on is to turn input 3 on. If input 3 is on and inputs 1 and 2 are on Y1 will be on.

Reverse
4. When inputs 1 and 2 are turned on output Y1 will be off and remain off until input 3 is turned on. Output Y1 will remain on after input 3 is turned off as long as inputs 1 and 2 are on.

If you change it to read the correct way it makes more sense. It sounds like a latched output. Input 3 would then be the unlatch, although the last line does sound kind of hoakie. If inputs 1 and 2 are on when 3 is triggered then Y1 would turn off, but then come right back on.

By using just using and OTE for Y1 and a seal in circuit as rdrast suggests the output will behave as described.

ameuba10 · Sep 25, 2008

yea i know that its worded weird. but i copied and pasted exactly what he had as our project. it doesnt help that i dont know what the heck im doing but when he has X's and Y's and lights and stuff it just throws me completely off. like it doesnt make since when i read it. but just to let you know, i finished 2 of my other projects. i just dont know wth to do here.

tragically1969 · Sep 26, 2008

Start By Doing What You Have Been Told So Far !!!!

Write A Logic Table !!!!

Mickey · Sep 26, 2008

ameuba10 said:
yea i know that its worded weird. but i copied and pasted exactly what he had as our project. it doesnt help that i dont know what the heck im doing but when he has X's and Y's and lights and stuff it just throws me completely off. like it doesnt make since when i read it. but just to let you know, i finished 2 of my other projects. i just dont know wth to do here.

Start at link below:

http://www.plcs.net/contents.shtml

Help with Program

ameuba10

Member

tragically1969

Member

ameuba10

Member

rdrast

Lifetime Supporting Member

mvandyke

Member

ameuba10

Member

dmkar

Member

tragically1969

Member

milldrone

Member

randyk

Member

LJBMatt

Member

LJBMatt

Member

ameuba10

Member

tragically1969

Member

Mickey

Lifetime Supporting Member

Similar Topics