Logic Diagram Software

John Marston

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Join Date
Apr 2015
Location
Chuparosa
Posts
54
I've been getting a lot of requests from customers lately to provide logic diagrams. In the past I've always declined but now they're getting pushy. We've been using Autocad for this but it is very time intensive.



Do you folks have a software that you like for creating Logic Diagrams?
 
for flowcharts, i would use Visio or Excel flowchart symbols. the biggest pain with excel is resizing the boxes for the text.
I have seen visio and it's pretty neat. Excel is what i used.
timing charts is another matter, never had to do one of those.
james
 
wow, this brings back the memories when I did P&G projects. I had to do so called "English Logic" diagrams. I did this one project where every PLC programmer quit and got stuck doing 10 unit operations and conveyor in a paper towel factory room. It was just two lines of towels. I think I had like 10 cad operators behind me doing cad. This was like the 1996-8 time frame. After that mind numbing experience I swore off doing that stuff ever again.

I remember some of the other companies I worked for had some sharp cad operators that had semi automatic tools or Lisp routines that generated a lot of the work. Like drawing the different symbols, and or, xor gates. The gate would represent either contacts in series or in parallel Maybe look at cad forums and ask around.

I remember Taylor software had a program that generated these type of diagrams but that was like 30 years ago. I bet they are out of business, it was a company out of Canada.

I would put an adder in your quote to provide these diagrams. Get a 3rd party cad house to quote this for you based on the specs that the end user would give you. Once they see the price they would back off asking for them.
 
for flowcharts, i would use Visio or Excel flowchart symbols. the biggest pain with excel is resizing the boxes for the text.
I have seen visio and it's pretty neat. Excel is what i used.
timing charts is another matter, never had to do one of those.
james




I hadn't thought about Visio but I used to use it for block diagrams and it worked great. I'll have to take a look at it again.
 
I would put an adder in your quote to provide these diagrams. Get a 3rd party cad house to quote this for you based on the specs that the end user would give you. Once they see the price they would back off asking for them.


Haha, now that is a great idea. I love it. I really hate making logic diagrams and this may just do the trick.
 
Why not program in ladder and print it out? Then your logic is there for anyone to see.

Ah...no.

Diagrams like this should communicate to non-programmers what the expected operation of the equipment/process will be. It should be used as an engineering document to tell others how to program it, and/or be used in conjunction with FAT/SAT testing to ensure that ladder logic you wrote does what you expect it do.

"As you can see from my printed logic that I gave you earlier for this test, the results of the hoist crashing into the barrier do confirm the system works exactly as programmed. Yes I do see that there is a photo eye available to detect an overshoot, and given the crash one could be lead to believe that this test is a failure. However, my printed logic, which I provided you to validate against clearly doesn't have the photo eye as part of the document. Therefore I would call this a successful SAT."
 
Programmer making the logic diagrams for their own programming? That sounds redundant in my ears.



At my previous employer we did logic diagrams for our equipment.
This was usually 100's of pages describing the programming function in detail, yet on an abstract enough level so that it would be platform agnostic.
This was input to the programmer contractors which we would use in a FAT/SAT against the programmers to check if they did it right.
We used our CAD system Elcad or Siemens CAD system COMOS.
 

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