PLC Programming

I have been given a problem in which i need to solve, i need a liquid container to fill 100 bottles with 50ml of liquid, which are been driven by a drive belt. once the bottle is posistioned correctly i need a 2 second timer for the valve to open to allow liguid through after which it closes making a counter recognise this and giving it instruction to compete the process another 99 times. The container has enough liguid to fill all 100 bottles.

please ask again if you dont understand the question

and please help me lol

what is the question?

panic mode said:

what is the question?

Click to expand...

Isn't it obvious,the question was "Will you do my home work for me?"

Shaun,

Help us to help you. I know you know all the problem (you do, don't you?) but we don't. Don't make any assumptions about our level of knowledge or understanding of what actually is your problem. Spell it out to us.

Are you intending to use a PLC in this? What signals do you have available to you e.g. bottle in place etc? Do you need to design a PLC program to control this? Is this the problem you have been given?

Try listing exactly the sequence of events as you understand them, and what will cause the operation to move from one event to another. For example -

1) Move belt (are you controlling this?)
a) Bottle detected in place? (how?)
2) Stop belt; open valve (how?); start 2sec timer
b) 2sec timer elapsed?
3) Close valve; reset timer; increment counter
...
...

Do this in more detail. This is fundamental to designing your program. Do it a second time with even more detail. And again. Pretty soon you'll find PLC code emerging in front of your eyes. You'll note I've not added anything about checking how many times these steps have been executed. What do you intend to do once 100 cycles have been completed? Stop forever? Decommission the machine? What if you move the belt but no bottle is detected? You need to start building in all the what ifs. But get the basic framework right first.

Then ask us for help again.

Ken

attempt 2

a two second gravity feed of liquid, 50ml is to be poured automatically from a large reservoir tank into small bottles as they move along a motorised conveyor.

while there is liguid in the lank a green light needs to be lit

when there is no liguid in the tank a buzzer must sound and the grren light must be replaced with a red one, forcing the conveyour motor to stop.

I must complete

• sketch your arrangemet
• produce an input/output list for documentation purposes
• make each lamp and warning device resetable
• the system must be designed so that the conveyor cant run with a red lamp or an audible indicator
• a counter must be included that counts every small bottle that is filled. the reserviour holds enough liquid to fill 100 bottles
• the red warning lamp can be improved to flash when the tank is empty
• additions or any other improvements to this system can earn distinction level grades

This is all the information i have avaliable to me, i am assuming they will just want the process to shutdown once the 100 bottles are empty

You see, it's starting to work!

You've now mentioned red and green lights and a buzzer that weren't there first time round. This is the kind of detail you need to identify to yourself.

Keep going. Do it again. And again. So let's see what's you've got so far. Have you sketched your arrangement? Have you produced an I/O list?

Come on Shaun, learn! Believe it or not we're with you on this, but we won't do it for you. You're like someone wandering in to a restaurant and saying "I've got to cook a meal. Can you guys do it for me?" Well, yes, if you pay us we can. Or because the chefs here are really kind and enthusiastic we'll help through the process out of the goodness of our heart. But you don't even appear to written your own menu yet. If you came in with some chopped onions and some herbs and some meat we'd say "OK here's a guy that doesn't want soup or dessert, and he's begun the preparation work on his main course. Let's help him along." So let's see your preparation so far.

Enough of the extended metaphor.

Regards

Ken

inputs so far

start button
stop button
reset button
inductive probe
liquid in tank sensor
timer signal

outputs

flags
motor
timer output
valve open
red light buzzer green light

i have sketched the arrangement aswell it jus needed to be a simple drawing

shaun

Hi Shaun

As an aid use the Prog and Doc Pads that can be downloaded from

http://www.industrialtext.com/freestuff.htm

Can you post the sketch? A picture paints a thousand words!

Regards

silva.foxx

picture of the arrangement

i hope this picturehas worked

struggle

im finding this a real struggle seen as this is my first time i have done anything like this, anything you think myt help will be widely appriaceted.

shaun

just follow your list of tasks:
- make representation (sketch)

- make I/O list ---> you need to work on this one, I suggest to make it like table with for example three columns that include address, device type and device function)
for example (just picked Mitsubishi since you didn't mention PLC type):

X0000 - Push Button - Start
X0001 - Push Button - Stop
X0002 - Push Button - Reset (reset WHAT...)
X0003 - Inductive sensor - Bottle present (just a WAG)
X0004 - Level Sensor - Liquid Level Low
;;
Y0000 - Green Indicator Light - Liquid Level Ok
Y0001 - red light - Liquid level too low
etc.

- etc.....

Contact type & voltage in another two columns