Direct Logic 06 Need Some More Help

Well I Believe I Have Figured Out The Counter But Now Im Not Sure How To Start Writing A Program. I Have Read Alot On The 06 And Ive Filled In The Blanks On Alot Of Unknowns But Im Still Struggling On A Few Things The Program That I Need To Write Should Be Really Simple Just A Couple Photo Eyes To Count For Inputs, And A Couple Of Outputs To Fire 2 Solenoids, Oh And I Want To Control My Coils On 2 Motor Starters, And The Whole Thing Will Begin With An E-stop Either Open For Off Or Closed For On, I Can See The Whole Concept In My Mind But Just Cant Lay It Down In Logic. This Project Is Pretty Basic Thats Why I Choose To Use A Plc I Thought It Would Be Great For Learning, Any Help Would Be Much Appreciated

1. Hard wire your Estop function. Feed the status into a PLC input. Don't rely on logic to keep people safe, use a Master Control Relay circuit.

If you will describe what you want to accomplish, I'm sure myself or someone else can walk you through creating a program. First, describe your process, then break it down into if-then statements. After you have that, you can work on the PLC logic.

JMO,

Marc

Ok Basicly Im Running A Stacking Machine That Counts Tortilllas They Are Feed In 2 Rows Side By Side And They Drop On A Platform For Stacking But I Need My Stacks To = A Certain Count Once The Count Is Met The Platform Drops And The Stack Exits For Packaging Each Row Needs Its Own Photo Eye To Count Because The Rows Will Not Equal The Same Count At The Same Time So They Should Be Independant From One Another And I Know The Whole Thing Will Work Off The E-stop To Start The Machine I Hope This Helps You So You Can Help Me
Travis

Ok. First off let's create an IO list. It looks to me like you have:

1 Estop Input
2 Photo Eyes Inputs
2 Motor Starters
2 Solenoids

Does this cover your IO?
What do the motor starters run?
What do the solenoids run?

Marc

Yes This Pretty Much Covers My Io, The Motor Starters Run The Drive For The Infeedand The Exit Conveyor Both, Thats 1 Starter, Thr Other Is A A Fan Motor That More Or Less Creates A Vacuum On The Belt To Hold The Tortillas To It. The Solenoids Control The Pneumatic 4 Way Valves That Supply Air To 4 Cylinders( 2 Cylinders Per Valve) 2 Cylinders To Each Platform To Drop The Stack On The Exit Conveyor Once The Count Is Reached And Then It Must Go Back Up To Start A New Stack, The Process Starts Again

Have you wired your IO yet? Do you have manual control of each Output?

Break your process down similar to as follows:

1. Infeed conveyor on, load tortillas.
2. Count tortillas until count = 10.
3. When count = 10, start conveyor and vaccum.

Etc.

Then we can start working on PLC logic.

As Of Yet I Have Not Wired Anything Im Still Trying To Fit Everything Together, And I Have No Manual Control Of My Outputs. Maybe Thats What Im Looking For Is Where I Should Start At You Know Point A-z

1. IO List.
2. Wire IO. Use the .pdf off of Automationdirect, it's got good schematics.
3. Proof that you have manual control.
4. Create a process flow chart. Describe what needs to happen to operate your machine.
5. Create logic for process flow control.

#5 is what everyone wants to jump to, but 1,2, and 3 set the foundation. 4 will give you the blueprint for 5.

thanks marc thats what i was looking for im going to get started as soon as i get back to the plant thanks again.

travis

Travis,

You can make it even easier to understand. For CroCop's Item 1, I suggest that you substitute this:

1A. Make Output List. *(see below for explanation)
1B. Add Output Rungs in Ladder Logic.*
1C. Add Inputs.*
2. Wire IO. Use the .pdf off of Automationdirect, it's got good schematics.
3. Prove that you have manual control.
4. Create a process flow chart. Describe what needs to happen to operate your machine. Compare and make this the same as your PLC program. I know, this is backwards from the reccommended procedure, but hey, that is the way most of us work!
5. Print out the process flow control chart.

* Explanation of Changes

1A. Make Output List. What Outputs do I need (or have available) to make the project work? The Outputs are the place to start, especially for beginners. It is the Outputs that do the work and create the results, but for some reason this is the LAST place that most programmers think about. A list of the Outputs becomes a simplified Flow Chart at this point in the program development.

1B. Add Output Rungs in Ladder Logic. Add an Output rung for each of the Outputs. Do not worry about Inputs, or any program error message that you see at this point. Label and add comments for each of these rungs. Only if you get the Outputs set up properly can you expect the program to work. Here is where you get to add your Outputs in the order that makes logical sense for you. For example, the first output that must be turned on can be assigned to the first available physical output (O:1/0 for example) and is the first ladder rung in the program at this point, the second one can be O:1/1, and so on. If you place them in the program in some logical order as much as possible, it makes everything else easier.

1C. Add Inputs. Start at the top of your laddder and ask yourself, "What Inputs are necessary to make this Output work?" Forget all other outputs while you work on getting this one to work. Add these Inputs (and any internal bits) to the left side of each Output rung. Try to have only 1 rung for each Output, but insert new rungs and add Timers, Counters, and so on, above each output rung for which those things are associated. Add labels and comments so that anyone could figure out how it works.

Excellent It Makes Sense I Never Would Have Thought About Adding Outputs Before Inputs But That Makes Perfect Sense. How Do I Get To The Pdf At Automation Direct? And Thanks For The Help I Need All I Can Get.

Travis

For Automation Direct PLC on-line manuals, start at this link:

http://web2.automationdirect.com/static/manuals/index.html

Lance,

I like that approach. Very intuitive. Very specific and easy to use for ladder. I'll be sure to pass that one on!

Travis, CroCop,

Thanks for the compliments. I have picked up a few shortcuts and handy tricks over the years.

Lancie