Hello,

I'm a student who's doing his final project which is an internship at a company. For this project i must research everything i can about OPC because the company wants to know if it's a venture worth pursuing.

The problem i have run in to is that since they aren't a member of the opcfoundation i don't have access to the specifications and the like and i think i need that for my project to be a succes.

Since they want to know if it's possible to integrate it with their software i must be able to write a client, but i don't want to do that yet without enough information and if it's possible to write a client for software that's written using delphi (read something about a automation wrapper for that).

I have found several pages with some information and the like including the ones mentioned here.

The question is if their is a way for me to get more indepth information? and i know if they were a member it wouldn't be much of a problem but since they aren't i am a bit stuck.

if my english is a bit on the poor side i would like to apologize for that, but i'm from the netherlands so english isn't my main language.

greetings Dennis

 

OPC is a fairly small club. There's not much real information available on the details of how OPC works if you're not a club member. What I have seen tends to talk around the issues rather than dealing with them in a straight forward manner. It is amazing how many words some people can use to say nothing.

Even if you had the specs, there is no guaranty that they would contain all the information you would want. The version of OPC which is being used today is based on Microsoft's COM/DCOM software (a method for programs to communicate with each other). That part of it is proprietary to Microsoft, so it is inevitable that there is going to have to be a lot of hand waving when describing that part of OPC.

I would suggest that you type "opc delphi" into Google and start working your ways through the links. I just tried this, and there were a number of links offering source code samples and free demos.

Something else you will want to research is what is meant by "OPC" and what your company wants out of it. There are many different "flavours" of OPC which are meant for different purposes.

The OPC club has come out with a new version of OPC which is intended to replace existing versions. As I mentioned above, the old style OPC is based on Microsoft's COM/DCOM. COM/DCOM has always been the Achilles heel of OPC and the source of many headaches for users. The new version supposedly dispenses with it and replaces it with a software stack that the OPC club came up with for themselves.

There are some books that you can order from the OPC foundation ("http://www.opcfoundation.org/"). I can't tell you if they are any good though.

 

Dennis,

A good place to start is to purchase the OPC Book.
OPC – Fundamentals, Implementation and Application third edition.

You can find this at www.softing.com for about $95.

It offers good starting point information with code examples and tools you can use.

Also www.kepWARE.com provides code examples VB6, VB.NET, C and more with there OPC drivers.

Both companies want you to learn as much as you can about OPC and they are willing to teach you at no expense. You are there future sales.

Read all you can, at both Web sites and you will be off and running in no time.

They have references to other vendors providing you with additional information.

Its fun stuff, Good Luck....

Gary Dudley
Automation Engineering
BP Exploration Alaska Inc.
Office: (907) 659 5969
Email: [email protected]

 

I think you need to be CLEAR about what exactly is required - I often hear the term OPC tossed round like a magic pill; people with a $50 serial products latent "If we only had a built-in OPC server ..." but that's not possible.

Which of these situations explains your company?
1) They make a software tool which needs to query existing OPC servers?
2) They make a hardware tool which needs to be queried by other software & customers ask for OPC.
3) They make both software & hardware, and now want to *ADD* a true OPC link in between.

For situation #1, sellers like Kepware should have free .NET or VisulaStudio examples which enable a Windows application to use other people's OPC servers.

For situation #2, adding Modbus/TCP or other common non-OPC protocols is the fastest way to enable OPC servers to talk to your hardware (you likely do will not want to add an OPC server to a field device)

For situation #3, fastest solution might be to look at some of the "user-configurable" OPC servers. You'd still be buying an OPC tool (and I know some companies abuse interns by asking for free miracles - sorry, can't help with that).

Bottom line - anyone who wants an OPC tool written and cannot afford to join OPCFOundation is not being realistic.

 

In reply to Lynn August Linse: In your situation #3 ("They make both software & hardware, and now want to *ADD* a true OPC link in between"), if someone controls both ends of the link, why would they want anything to do with OPC? That would have to be the hardest possible way to do things. I'm not disagreeing with your overall conclusions, but situation #3 should be another case of "do it some other (easier) way".

However, you left out situation #4, which is what I suspect is the case here:

4) They make a software tool which needs to be queried by existing OPC *clients*.

There are "data historians" and other such things that work this way. If they are doing that, then they need to write a client application to run automatic tests on their product so they can see what is working and what isn't. That sounds like the sort of project that someone might give a student.

 

From what i gather situation 1 is what they want at the moment although they will probably write their own OPCserver too, but that's because they use hardware with no OPCserver available. IF they want too use it in that situation they would need too write their own server. And they use their software as a client/ server already so they can troubleshoot clients from were they are situated more easily.

But at the moment all they really want too know is what OPC is, how it works, if it could be integrated in their software and if it's a worthwile idea too put time and money in.

At the moment i am still reasearching what OPC is how it works etc and working too udnerstand their own software. I have found the examples you talked about and even some servers i can test.

thank you for your answer greetings

 

In reply to the last two replies,

The program that they use is divided in different parts.

They have a program in which you make a template. In this template you make the basic userinterface. After done with the basics you can then choose which weighbridge, badge reader, PLC, screens or other devices like that that you want too add. You can select which driver too use for a particular device and the preferred parameters.

You can also define how the template works behind what you see. So for example if you fill in field a you could define that it automatically fills in fields B till H if their is something in the database for those fields of course. The complexity of how it works is rather overwhelming for a beginner although i think i'm making good progress.

If you have your template ready you can load it in the program that let's the program work for you.

Their are other programs but i haven't had the time too see what they are about but these two are the most important.

If I understand OPC a bit correctly. I need too make sure that in the template configurator a server can be chosen and then per device that they want too connect set which parameters should be used.

And then the program which runs the template should have the actual client.

I hope i'm a bit n the right track.

thank you for all your reply's you have been a great help so far.

greets