I'm trying to program 5k loadcells from motherboard/relay logic to SLC 5/05

I'm new to programing, but not PLC's. I'm trying to write a program using either a SLC 5/05 or ML1000 to use the weight of 5k load cells to determine how long each componet (plastic pellets)should be dispensed. I basically want to dispense virgin material at any % I choose, calculate that weight, dispense regind % then the % of color until I have a total batch weight.

Go ahead a give the program your best shot. Post your code and someone will help you out.


Ken

Thanks Ken, but I'm sure my bet shot will give all of you good laugh.

by attempting to write the program and then posting your code, it will be easier for someone to get a grasp of exactly what you're trying to accomplish. Be sure to document you logic well.

Ken

I just can't get over the hurdle of getting the program started. I guess I'm using the load cells as a starting point, it probably should be is the d-box empty, if so then.......... talk about a dull life I spent 6 hours at work today on this, now my wife's shopping and what am I doing?

Give it a shot, you'll get more replys if you show what your trying to do. If your using a 5/05 include all the modules and start trying to write the program, if you get stuck write what your trying to do and post what you have written.

Just about everyone here will try to help you, as long as they see you are trying. Some may give you a hard time, but at least your trying.

I guess that's why I'm here, I'll put it together then the pros can tell what I'm doing wrong, thanks

An alternate method - if you have the equipment available - is take it one step at a time. Start with a minimal program then add to it. Finish each step before going on to the next. The individual steps are mor easily managed.

1. Can I get a weight from the loadcell? If not, is everything hooked up correctly?

2. Is the weight accurate? If not, what do I need to do? Is the problem mechanical or a scaling problem?

3. Can I turn on any flow of material? Can I stop it? Can I stop it at a certain weight of accumulated material?

4. Can I calculate and use percentages to derive weights of the three types of materials?

5. Can I make a proper receipe mixture of the materials?

Then other things to consider for a real system.

6. What operator controls are necessary fo proper operation?

7. What safety items are necessary to prevent the operator being injured or killed?

I agree with bernie. Your best bet is to break it up into as small a byte (pun intended) as possible but still perform the function intended.

Gjbsr,

I mostly agree with Bernie and Testsubject, that you need to break up the problem into smaller steps. However, my programming philosophy differs from theirs in that I always start with the Outputs, not the Inputs. If you ask the question, "What am I wanting to DO?", then the answer always involves the PLC Outputs, not the Inputs such as your Load Cells. You did not even mention what your Outputs will be, so I am thinking that this is a major stumbling block for you. I think you will probably have some solenoid valves to operate bin dump valves, and maybe a motor starter output to operate the re-grinder.

Reasons for starting with the Outputs:

1. Defining all you Outputs up front helps to clear up the problem and streamline your thinking. It means that you know exactly WHERE you are going.

2. The last command on a PLC rung is an Output. If you can define all your Outputs, then the rest of the programming becomes fill-in-the-blanks to make the outputs work. I often start a program by inserting a rung for each output, with it labeled and commented, and the Input side completely blank, to be filled in later. This works because each Output should appear only once in the program, where as Inputs can and will appear many times. Don't knock it until you have tried it!

3. There are usually many fewer Outputs than Inputs, so it is easier to get those completely in your mind than it is to try to remember all the Inputs. Outputs are more fixed, more permanent, and harder to add to, whereas Inputs should be more flexible and you may find, once you define your Outputs, that you actually need a different Input than originally planned.