Conveyor Belts that uses PLC's

Please help me with the following ladder logic Diagramme:-

Develope a Ladder Logic Diagramme that will make use of a conveyor belt in conjuction with a start and stop buttons as well as two IR sensors that will distiquish between two different length boxes.

The IR sensors are placed a certain length apart. Should a box be too short to activate both sensors, a solenoid must be activated, kicking the box off the conveyor belt before it reaches the end of the coveyor belt.

N.B. Hand in Date :- 24th of July 2007

I think you´ve been sleeping in the classroom or skipping classes, otherwise you would´nt be here asking this kind of questions all the time & please, STOP spamming the same topic again. Ok ?

First, make a point list of all the I/O. Then make a text description of the operations, with details of the sequence. Then start writing logic to perform the sequence you have described.

Post your work here and you are more likely to get help. We don't do homwork for you , but we will make suggestions on your own work.

And by the way, we don't share your sense of urgency, so posting your deadline isn't going to help.

Im beginning to think this guy is some sort of troll, add to that the fact he's beginning to take the preverbial a little !!

best ignored i think

Here ya go -- I hope Logix5000 is the right platform for your homework. If it isn't maybe someone can convert it...

Learn it well. It'll help in real life!

Nice one OZEE

Too funny!!!!

please pay attention, what u miss in school will make u weak in this point all ur life. beleave me it is a chance to get free knowledge, maybe this will help (picture attachment).

i'm a biginner myself, so plz double-check

Mico, your code would start the conveyor but everytime the sensor is activated the pusher would push.

What he wants to do is use 2 sensors and know if a box is a specific length.

joeboy, as mentioned you will need to offer something to show you have made an effort of your own, then others will help you to understand.

This site offers a simulator, look on the top of the page, this may help you too.

To get you started do as mentioned by Tom, determine what your inputs and outputs will be, write down the sequence then determine how to make the sequence into code.

I will offer a hint for one method. You can start a timer when the box passes Sensor1. If Sensor1 and Sensor2 activate then reset the timer. If timer times out then box is too short so activate puser.

How it is done depends on how detailed you want it to be, may need to insert another timer to provide length of the box then use another timer to make sure it is positioned in front of the pusher properly.

As others said, make an effort then you will get plenty that will help. I suggest you just read some of the threads here, start with this one: http://www.plctalk.net/qanda/showthread.php?t=11015

Another: http://www.plctalk.net/qanda/showthread.php?t=22335

I offer these because the poster (Paula) goes into details about the machinery, this gives you an idea how to approach situations.

Try something like this, except use the second sensor to detect length instead of level:

Any comments on the example below?

What is -|N|-?

a falling edge one shot, Modicon style.

That is what I thought but wanted to make sure, in that case when Sensor 1 is energized and Sensor 2 NOT energized the reject would turn on for one scan, unless Modicon works different then those I know.

Since there is postion involved i.e. the box has to have time to travel from Sensor1 to Sensor2. You do not have to use a timer, you could use some kind of conveyor belt feedback using an encoder or sensors i.e. once Sensor1 is active then after X amount of counts Sensor 2 should be, if not, then X counts later reject box.

Retry:
Sensor A is first to be hit by box, if when the box leaves sensor A it hasn't yet hit sensor B it rejects.

I am a student too, not a teacher or adept.

That could work, if the reject is a cylinder with auto return then reject completed could be a sensor to show it fully extended, once sensor made then resets and cylinder retracts.

Not sure how far this student has gotten or what the instructor may expect. I would think that the student would have to explain exactly what is being done and possibly be something that could be realistically accomplished.

What is not taken into account is "position" i.e. to reject a part from a conveyor you have to know its position so you can reject it at the proper moment.

Hard to know what some students want/need, like the original poster they just come here to get their homeword done and rarely participate or respond.

As someone noted, in graphic detail, on one thread, I sometimes have a tendency to spoon feed the answers.