daba said:
...This is not an argument that anyone can win...
daba,
This is what I'm trying to point out but you have probably summed it up far better than I have managed to so far. I am not in any argument here about which should be used or not. I'm more pointing out that to argue for one or the other, exclusively, is futile until you know the application specifics and dependencies.
I edited that in as you posted before I had the following just finished...
dmargineau said:
...Read Post #1 again; and again;...
You are telling me to do something I have already stated as done. I can nearly quote the opening post for you at this stage, as can I recall their second and subsequently last post, which has not yet been mentioned. But that will come.
You are not opening my eyes to anything here. I know what the OP asked and the various ways in which it can be interpreted. I have already said that you could be right, but cannot be certain, yet. But you are ignoring my points that may prove to disarm you, or meet you half way and focusing on the argument that I'm not having with you...
dmargineau said:
...where is any reference to messaging?...
There is no reference to messaging the same as there is no reference to Produce Consume being an absolute prerequisite. However, the latter can only be clarified by the OP, whereas, until the OP clarifies said latter, the former is still a valid "other option".
dmargineau said:
...Does P/C function akin to messaging as some 16 year veteran thought all along up until yesterday?...
Are you seriously asking me that question? If you really want me to explain how "I" think they both work and what, if any, similarities they may have, then ask away. I'll be glad to keep you reading for the foreseeable.
I have at no point stated or suggested that Explicit messaging and Produce Consume are interchangeable. Please stop dragging me into the "proponents of using messaging over P/C" catagory. I've already explained that I do not take sides here. Choice is King. If you limit your choices in this business then I would say that that is somewhat unprofessional.
An honest question for you...
When would "you" use Explicit messaging between two or more Logix controllers?
I know what options are on the table here, and until the application dependencies are clarified (possibly might not happen now?), then those options will remain.
Moving on...
Knowing that the OP could not acheive their goal using Produce Consume while the controllers are operational, DBLD99 replied to a request for "other options". Other options could imply other options of implementing Produce Consume only, or it could imply other options alternative to Produce Consume. I can sensibly come to that possible conclusion. Can you, dmargineau? That's another honest question by the way.
Here is that reply providing an "other option"...
DBLD99 said:
Depending on Version of 5000 - You can create a UDT with everything you need and a SPARE DINT[xx] and REAL[xx] online. Reason for the spares is once you create it and utilize it with a tag you won't be able to change it online anymore.
Then use regular messaging. We have actually gone away from P/C tags lately and gone back to messaging. Way easier to maintain when you can't shut things down.
AutoMax said:
Yet another poster slagging produced/consumed tags...
I don't see any signs of "slagging" the Produce Consume model here? They have, for their own reasons decided to primarily use Explicit messaging over Produce Consume. Whether I would endorse this biased practice is another matter. It can appear to be a somewhat poor practice on the face of it. It is certainly not easier to implement, the most reliable, or the intended goto method for the Logix platform. But again, I don't know the applications that it's being implemented in, so it might suit their needs.
I don't advise anyone, uninformatively, to use one method or the other. Give me the application's specification and then it's a different matter. I could then advise ad nauseam. Then I would be as passionate in my replies as you are, if I felt that someone was being led astray.
dmargineau said:
...why are you presuming (George?) that he/she is not aware that he/she could programatically implement data exchange?
I don't like to blindly assume or presume to know anyone's experience on a given topic. I prefer to ask or summise as best I can.
Our OP's reply to the above "other option"...
mjosephs said:
How would I go about using a UDT to let the one PLC read specific tags from the other? I'm currently using Version 30 of Studio 5000
With respect, the above has "I'm not too sure about all this" written all over it. It suggests a level of uncertainty about UDT's and how one would use messaging with such UDT's. If our OP was au fait with messaging, as you suggest they most likely are, and I am incorrectly assuming they are not, then their last post would not imply as such, to me.
However, you have made a valid point here...
dmargineau said:
...I firmly believe the approach basics are more important than the apparent end result...
This is also my belief. We should always endeavour to explain the basics, or fundamentals to an OP, especially when they may appear somewhat "Green" on a subject. The fundamentals of communicating tag data between two or more Logix controllers should include both methods. If Implicit is a requirement, then you can point out the pitfalls of using messaging over Produce Consume. But why say you that when you seem to think they are not so "Green"...
dmargineau said:
...The question was about Produced/Consumed tags; there are NO OTHER OPTIONS for Produce/Consume handling as of today; period; the OP was inquiring of another way (short of Offline & Download) of creating P/C tags; I am pretty sure if he wanted to MSG data he would have not asked here about Produce/Consume; why are you presuming (George?) that he/she is not aware that he/she could programatically implement data exchange?
That doesn't sound like you think they need to learn anything other than what you have provided in Post #2, or since?
If you happened to be incorrectly assuming that they only want a Produce Consume type option here, and nothing else will do, and the OP said no, messaging will fit the bill nicely, will you then yield?
Or will you then move to them and start calling them amateur and unprofessional for not using Produce Consume, regardless of what the application will allow?
This is not an I'm right your wrong scenario. I don't care which way it slides as long as the OP has all the possible options made available to them. If the application specifications narrow, then the options will narrow.
But I don't choose, nor recommend others to choose, to close off such possibly viable options, until that conclusion can informatively be reached.
Please don't continue "SHOUTING" at us/me about when/where/why the Produce Consume model should always be used first and how the use of Explicit messaging is a "band aid" solution.
Members are already starting to point out cases here for you, for and against both methods. As did Firejo in that other thread you linked earlier. Which I also fully read.
One size does certainly not fit all here.
G.