Use of memory/marker bits in an FB on S7

[AndrewM]

You could add these variables to the FB interfaces (IN_OUT) and pass them between each other.

In one of my versions I tried this method, for some strange reason when I moved between FB's one of the stages didn't reset so I had 2 stages enabled together(not good), so being a novice I wasn't sure whether this was a workable solution, but now you've mentioned it I might revisit it.

 

[AndrewM]

How will you test your implementation - using PLCSIM or some real h/w ?

Unfortunately PLCSIM

 

[L D[AR2P#0.0]]

99.9% of the type of problem you mention in the previous post is down to a coding error and not some fundamental limitation of the plc.

If something happens that you don't understand, don't ignore it as it will come back to bite you later.

 

[TurpoUrpo]

Want to give whole coursework description? we can also comment on your code, if you want to post it.

 

[L D[AR2P#0.0]]

Unfortunately PLCSIM

That is good news - we can run your code in the same environment when you hit other problems.

 

[AndrewM]

Want to give whole coursework description? we can also comment on your code, if you want to post it.

How do I post it, are you just wanting screenshots or the whole program archived?

 

[TurpoUrpo]

How do I post it, are you just wanting screenshots or the whole program archived?

You can put in on library, then it will fit on forum limit.

 

[L D[AR2P#0.0]]

As already stated, the complete project is usually too big to post on here. To post the code, create a library instead of a project. Insert an S7 program into the library then copy the blocks from your project blocks folder to the library blocks folder. Archive the library and attach to a post.

 

[AndrewM]

As already stated, the complete project is usually too big to post on here. To post the code, create a library instead of a project. Insert an S7 program into the library then copy the blocks from your project blocks folder to the library blocks folder. Archive the library and attach to a post.

Would you beleive it, I converted it back to old IN/OUT version and its now working.

I have attached a copy for you to have a look at, though its nothing to get excited about.

Any comments welcome I think

 

[AndrewM]

Want to give whole coursework description? we can also comment on your code, if you want to post it.

Hi TurpoUrpo

Attached is the coursework IO schedule I was given.

Regards Andrew

 

[AndrewM]

Just thought I'd mention for anybody looking at the project, it isn't totally finished, I have still to put some more comments and symbols in and check over how it reacts to alarms etc, just wanted to get it to a position where it actually runs first.

Regards Andrew

 

[L D[AR2P#0.0]]

Minor detail but, why is the Recipe capacity stated at 5 litres? Do you assume it is full and then count out 5 litres and stop repeating? As there is no feedback you will never know when it has been filled back up.

 

[AndrewM]

Minor detail but, why is the Recipe capacity stated at 5 litres? Do you assume it is full and then count out 5 litres and stop repeating? As there is no feedback you will never know when it has been filled back up.

Morning L D[AR2,P#0.0]

I'd not picked up on this, I will check with the course tutor, I have had parts in exercises before that are controlled by other areas.

Other than that, have you had a look at the program, how am I doing?

Regards Andrew

 

[L D[AR2P#0.0]]

If this is your first S7 program, then you are doing extremely well.

Are you intending simulating the tank feedbacks so your process can be started and then keeps going?

 

[AndrewM]

If this is your first S7 program, then you are doing extremely well.

Its virtually the first, so Iam really pleased with your comment, Thanks very much.

Are you intending simulating the tank feedbacks so your process can be started and then keeps going?

I am not exactly sure what you mean here, when I test the program I set the Input bits in the simulator as though sensor are being reached. ie set I0.3 for Tank1 Hi sensor.