one sensor

rubhan · Aug 5, 2004

one sensor to see when box is full
1 cylinders to move product into box (no sensors on cylinders)
gravity fed product is moved into box by 1 cylinder (double acting)
sensor is on until box is full
plc programming is such fun so this should be simple ?
please be kind and dont laugh to much, any help would be appricated
regards
rubhan

Bitmore · Aug 5, 2004

Not laughing,
What is the question?

rubhan · Aug 5, 2004

how would you use a plc to do this is the question
thanks

Fred Raud · Aug 6, 2004

whatcha got so far?

Fred Raud

rubhan · Aug 6, 2004

when sensor is off or on,do the following,i was thinking there was another way besides a jmp

Bitmore · Aug 6, 2004

MACHINE step logic, your sensor is your "eye"
or 5 line as we like to call it...
line 1
preceeding logic will confirm box located under loader cylinder and ready to receive load. (This is the first time to use the eye) is this a full box?
yes: go to line 5
line 2
local process ready? (pusher got stuff?)
no: go to line 1

line 3
perform local process (push stuff in box)

line 4
is local process done? (this is where the eye works) is the box full?
no: go to line 1

line 5
request next process

Hopefully this helped your thought process

bitmore

rubhan · Aug 6, 2004

like being ship wrecked ,bitmore states the obvious

i am asking for any one who can help use a single sensor
to complete a plc process

this is not the place to be "obvious guy"

Bitmore · Aug 6, 2004

this is not the place to be "obvious guy"

Don't really know what that means, I wasjuz' trying to hep'.
I try to be as "obvious" as I can. I don't bully or intimidate. I try to keep me, and my friends here, as informed as we can be. I joke with known knowledgables, and taunt the students and new comers, we all do.

rubhan · Aug 6, 2004

sorry "obvious guy" first of all you did not know what the question was , only after i posted the "did not want to use a jmp" did you get smart and obvious
i have seen what most of you do to new commers on this site
and it is shameful
you offer not thing but reduicule ,i truly hope to not become like any of you
i was hoping for pratical help
how ever it seems to be not forth comming
thanks
anway

Bitmore · Aug 6, 2004

The step logic is not a smart idea I just got,, and for Jumps you don't need them in sequential logic as long as you follow the 5 line logic. Each next step is only predicated by the fulfillment of the previous. Therefore simple Normally Open contacts that are held closed represent in logic the "ok" to proceed.
If the preceeding step has not been accomplished, the "enable or step bit" is not turned on for the machines process or "steps" to proceed.
You don't really need go to statements, I just wrote it that way to make it easier to understand step logic. Heck, if that were a "real" running program it would get lost.

rubhan · Aug 6, 2004

maybe i dont get it, i see no way of "asking" the plc if a sensor is on or off, it's input is either on or off, "as opposed to c programming" so with out a jmp i find it's not possible
any way
thanks for your help
rubhan

hd_coop · Aug 6, 2004

first of all you did not know what the question was

Reread your first post...your only question is if this should be simple.

i have seen what most of you do to new commers on this site

If you actually pay attention you will see that newcomers who actually put forth some effort will most certainly get helped. Those students who come here and post a poorly worded "question" can't reasonably expect a response.

i see no way of "asking" the plc if a sensor is on or off, it's input is either on or off,

I have no clue what this means....you don't know how to "ask" the plc if a sensor is off? Then you state its input is either on or off.
If the input is on, that generally indicates the sensor is on (in the case of a normally open sensor), if the input is off, that generally indicates the sensor is off.

Code:

  Sensor    Internal Bit
---| |---------( )

jrwb4gbm · Aug 6, 2004

Be nice rubhan and people here will help.

rsdoran · Aug 6, 2004

Bitmore explained it in perfect fashion, the job now is to use ladder logic to conform to that. Ladder doenst have to explicitly use goto, if, else etc but it works the same.

Let me explain this in another way. The application as you described it just states the box is to be filled. Place the box in position and push a button to initiate a start sequence, this in turn will turn on the output.....in front of that output is an xic --| |-- for the sensor....when the box is full that xic for the sensor will go false turning off the output. There are several ways to do this but I am a simple person.

Fred Raud · Aug 6, 2004

a little effort goes a long way

Fred Raud

one sensor

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