| View previous topic :: View next topic |
| Author |
Message |
jaro
Joined: 16 Dec 2004
Posts: 105
Location: Prosys
|
 Posted: Mon Jan 29, 2007 1:19 pm Post subject: |
 |
|
There is no real alternative for OPC, which is very wide spread in the automation field.
I suggest that you spend your money to a toolkit, in which case you can omit studying the specifications and concentrate on building applications.
For example, take a look at Prosys Sentrol, which provides you ready to use components for building an OPC client and server in a one day:
http://www.prosys.fi/sentrol.html
 |
|
| Back to top |
|
 |
micke_932
Joined: 07 Oct 2005
Posts: 4
|
| Posted: Mon Jan 29, 2007 1:40 pm Post subject: |
|
|
| I am aware of this, and this is a fine alternative if you work for a company, but in my case it is an open source project with no commercial funding, and then it gets more complicated. |
|
| Back to top |
|
|
jaro
Joined: 16 Dec 2004
Posts: 105
Location: Prosys
|
| Posted: Mon Jan 29, 2007 2:22 pm Post subject: |
|
|
OK, that makes it more complicated.
The problem with the openness of OPC is that the development of the specifications is based on companies volunteering to work on it - and they require some advantages in order to be willing to participate.
In your case, you might need to discuss if you could exchange some of your work to be used for developing the specifications (currently the OPC UA specifications) vs. getting the specifications for your project.
I am not certain if that is possible for non-members, though...
There are also some free samples around, e.g at opcconnect.com, which might help you, too. |
|
| Back to top |
|
|
SebV
Joined: 31 Jan 2007
Posts: 3
|
| Posted: Wed Jan 31, 2007 2:50 pm Post subject: Summary of the new politic... |
|
|
OPC UA shall (if I understand well) provide many advantages like support not only window platform, embedded system, various transport protocols supported...
Usually, there is some studies done by leading engineer who want to check if it is good or not to invest company money for new solution and drive the future solution... what is the best solution (buy API, do it yourself, drop the techno...)
The main worry of OPC foundation is: interoperability, plug and play, OPC UA stack reference maintenance. For a standard it is better that all of this working fine… For this the OPC foundation has also the compliance test that any product must success to be authorise to go to the market with OPC stamp. This test should be enough to guaranty the interoperability and plug and play…
For the maintenance, one of the best way is to continue its development as a OPEN project, like this every body could participate and improve the OPC UA stack with the source under control of the OPC foundation. (A win/win condition)
Of course the permanent member shall have an advantage for the definition of the evolution (they vote) and primo access to the specification and they definition (it is there interest). But other should be able to access to it to continue to improve OPC and provide it a larger support… RFC use open description and at the moment and I do not have problem to communicate under TCP/IP with various type of computer… The free access to the spec and reference implementation of the stack is NOT a limitation for the interoperability. The free access to the spec is a good way to promote the use of your solution.
Some time I am worry that the main worries of the fundation is not the develoment of the standard but to finance the structure (important aspect for every organisation)
PLease when could we have access to the specifications and later to the source code of the reference stack 
PS: For the one who want a good way to exchange information between device and supervisor, you have modbus… but many advantages we could find in modern protocol (IEC-104, OPC..) are missing.
 |
|
| Back to top |
|
|
Randy
Joined: 27 Feb 2003
Posts: 3523
Location: OPC Foundation
|
| Posted: Thu Feb 01, 2007 6:11 am Post subject: |
|
|
| Quote: | | I do not have problem to communicate under TCP/IP with various type of computer… The free access to the spec and reference implementation of the stack is NOT a limitation for the interoperability. |
If an end user buys a TCP/IP product that does not work they blame the vendor of the product. When an OPC end user buys an OPC product that does not work they blame OPC. That is the reality of the marketplace that OPC must deal with. That is why the OPC Foundation is working with vendors and end users to improve the quality of OPC products that go on the market. We felt that requiring vendors to become members before getting access to the specifications would encourage the vendors to participate in the various certification and testing programs. This would increase the quality of OPC products on the market and ensure that they better meet the needs of the end users.
Obviously, giving the specification and all of the code away for free would maximize the number of people building OPC products. However, the end users tell us today that they don't want more OPC products - they want better OPC products. That is why we had to make some decisions that would make some people unhappy. We feel that the current model is a balance between the desire encourage as many people as possible to implement OPC solutions and the need to ensure that those implementations deliver the quality demanded by the end users. |
|
| Back to top |
|
|
Mike Dillamore
Joined: 11 Mar 2003
Posts: 122
Location: OPCconnect.com
|
| Posted: Thu Feb 01, 2007 6:35 pm Post subject: |
|
|
FWIW, OPC Foundation president Tom Burke has undertaken to provide Open Source developers with free access to the OPC specs: -
| Quote: | So Here is my offer:
Any developer that does not want to be a member of the OPC Foundation but wants the OPC Foundation Specifications to evaluate the OPC technology, I will personally provide them unrestricted access to the OPC specifications as long as they provide complete unresticted access to any products they or their company has built in the last 10 years (matching the opc foundation 10 year anniversary) that I am alowed to provide to members of the OPC Foundaton for to evaluate and use for interoperability testing. Demo versions of products are unacceptable.
Developers also must be willing to bring their products to the Interopeability workshops and prepare for the grueling testing theat all OPC Foundation members go through to validate quality and interopaerability. |
See http://opcfoundation.org/cs/blogs/tom/archive/2006/09/22/14.aspx |
|
| Back to top |
|
|
SebV
Joined: 31 Jan 2007
Posts: 3
|
| Posted: Sun Feb 04, 2007 11:13 am Post subject: |
|
|
Dear All,
I already read the previous message in the forum, but it does not solve any problem, I do not own the source from my company... and you need to sign many NDA just to provide a copy of the specification. It is for this reason I consider the declaration more like humoristic than a real proposal.
To guaranty the OPC quality, all depend of the interoperability test than in all case is an obligation before sell any OPC product (with OPC logo). If the test is OK and it is not working, I need to complain about OPC.
In other case if it is not working I will not blame OPC, but the supplier who did not have the certificate from OPC foundation….
But let study another case (not mine exactly mine). A small company or software developer need to get few tags from an OPC sever (like for a web service or monitor a process with embedded system…). The easy choice could be to get the data by a small query, specially made. I recognize it is not fully follow the OPC spec, but it is enough for the service request and do not put in danger OPC standard. Interoperability is really important on server side, on client side I am not sure it is so critical…
Any way it is the fashion to lock the specifications, ODVA did the same with CIP (I still have the version before the lock, but no access to safety part of the protocol ). I also understand that the member that do product based on those specification are not too happy to see new competitor when the market become mature... |
|
| Back to top |
|
|
Borg
Joined: 25 May 2007
Posts: 1
|
| Posted: Fri May 25, 2007 6:26 am Post subject: |
|
|
The problem of the specifications being out of reach for individuals could be solved by the individuals forming an alliance or non-profit group and the group becomes a paid member. (PM me if interested).
My issue with 'Open' is that the technology seems to assume a Microsoft platform. COM, etc.
We also recently experienced the hefty fee for CIP specification and in the end it didn't really help as many vendors use their own extensions to the standard and simply will not release any information what so ever.
We now provide our own complete proprietary solution - hardware and software rather than someone else's.
My 2c. |
|
| Back to top |
|
|
rweaving
Joined: 01 May 2008
Posts: 2
|
| Posted: Thu May 01, 2008 5:38 pm Post subject: |
|
|
It’s really disappointing to see the OPC foundation’s lack of commitment to creating truly open standards. OPC UA is built upon open standards. I know that you can implement it without having to pay royalties. Randy seems to think that by raising the bar to entry that it creates “higher quality software”, this is flat out wrong, look at Microsoft. Security thru obscurity does not work, more eyes mean more opportunities to catch bugs. I think the OPC foundation should focus on certification as a means of funding. If you did open the spec, and even the code you would have more programmers interested in helping to work on the project, and make it a standard that could become widespread.
I’m not renewing my membership in the OPC foundation until they create a truly open standard as defined by the European Union (http://europa.eu.int/idabc/en/document/3761 ) or W3C (http://www.w3.org/Consortium/).
Ryan C Weaving |
|
| Back to top |
|
|
Randy
Joined: 27 Feb 2003
Posts: 3523
Location: OPC Foundation
|
| Posted: Thu May 01, 2008 6:25 pm Post subject: |
|
|
Ryan,
The OPC Foundation specifications meet all of the criteria in the EU document you provided except for:
| Quote: | | The standard has been published and the standard specification document is available either freely or at a nominal charge. It must be permissible to all to copy, distribute and use it for no fee or at a nominal fee. |
We plan to make the specifications available on a DVD for purchase by people who are not members once they are released.
UA will also be eventually released as an IEC specification which means people will be able to get the specifications from the IEC.
I am not certain why allowing others to redistribute the specifications is a requirement but I have forwarded the EU document to Tom. Our current policies are based on policies that other open standards bodies like ITU, ISO, IEC are using.
Here is the page for IEC industrial automation specifications:
http://www.iec.ch/cgi-bin/procgi.pl/www/iecwww.p?wwwlang=e&wwwprog=sea00227.p&progdb=db1&ics=25040 |
|
| Back to top |
|
|
rweaving
Joined: 01 May 2008
Posts: 2
|
|
| Back to top |
|
|
Randy
Joined: 27 Feb 2003
Posts: 3523
Location: OPC Foundation
|
| Posted: Thu May 01, 2008 9:21 pm Post subject: |
|
|
The $1500/year gives people access to much more than the specifications.
A nominal fee would be a couple hundred dollars. We have not set up the process for distributing the specs to non-members so we don't have a price list available. However, open does not necessarily mean completely free according to the EU definition of term.
I realize there is a disconnect between the way things are traditionally done in the industrial automation world (the IEC wants $1000 per document for Fieldbus specifications) and the IT world where specs are always free. I don't know whether the IEC will treat UA as an IT spec or an IA specification. If the IEC provides it for free then the OPC Foundation likely will as well.
That said, OPC is a member driven organization and if members believe that the specs should be made available for free then these members need to make their feelings known to Tom. |
|
| Back to top |
|
|
BrianT
Joined: 07 May 2008
Posts: 3
|
| Posted: Wed May 07, 2008 2:58 pm Post subject: Re: |
|
|
| Randy wrote: | The $1500/year gives people access to much more than the specifications.
|
Many people don't want or need (at least initially) more than the specs.
| Quote: |
That said, OPC is a member driven organization and if members believe that the specs should be made available for free then these members need to make their feelings known to Tom. |
The problem with that is those members have already paid for the specs - why would they want you to give to others for free what they had to pay for? That's like a TV station asking businesses who have already paid for advertising time slots if they want the TV station to provide free advertising time slots to everyone else.
| Quote: |
If an end user buys a TCP/IP product that does not work they blame the vendor of the product. When an OPC end user buys an OPC product that does not work they blame OPC.
|
I doubt this happens much, and when it does it would take only 30 seconds to educate the end-user. Product certification would also solve this problem.
| Quote: |
We felt that requiring vendors to become members before getting access to the specifications would encourage the vendors to participate in the various certification and testing programs.
|
Instead, you should only promote certified apps. If Microsoft tried with Win32 or .NET what you're trying with OPC, developers would jump to Apple and Linux in droves. With OPC, there's not really anywhere to jump to.
| Quote: |
This would increase the quality of OPC products on the market and ensure that they better meet the needs of the end users. |
In any other software market, the way it works is that end users shop around first, basing their purchase decision on company reputation and/or Certification of the software and/or reviews of the software. Quality products flourish, the others die off - you don't need to try to control that, the nature of market itself will do that. Certification helps both buyers and developers attain quality.
| Quote: |
Obviously, giving the specification and all of the code away for free would maximize the number of people building OPC products. However, the end users tell us today that they don't want more OPC products - they want better OPC products.
|
A janitor at ABB or TV salesman from Hitatchi, with no development experience but wants to learn OPC on his own, has full access to the specs and sample code just because they have an email address from a corporate member. Does that mean their software will therefore be of a higher quality than mine? I think not. University members have access to the specs as well (that's what it says in the member benefits .pdf, anyway), which means any student/staff/faculty/alumni from University members can freely access the specs, regardless of their "commitment" to OPC let alone any association with software development or engineering. On the other hand, people like me with many years of professional software development experience and an large interest in OPC are locked out simply because our current employers are not members. Perhaps I should sweet-talk a receptionist at any corporate/charter member company, or pay $20 to a poor Art History student at the University of Illinois to download the specs for me? I wouldn't do that, my point is only to illustrate that the claim that the current policy is in place for "quality protection" and commitment testing simply doesn't hold water.
So my suggestion is: 1. open the specs and sample code to everyone, 2. charge a membership fee for things like voting, input, event attendance, etc. and 3. charge a fee (or combine with #2) for product OPC logo certification. 4. Promote only certified software on the official site and in official catalogs, etc.
I will continue to try and learn/develop OPC software regardless of whether the specs and sample code are made freely available or not. And |
|
| Back to top |
|
|
BrianT
Joined: 07 May 2008
Posts: 3
|
| Posted: Wed May 07, 2008 3:00 pm Post subject: |
|
|
...continued
And there are many others like me - thus, withholding information can actually have the opposite effect from what the current policy is intended to create, for the software I create without any specs will likely not be as good as it would be if I had the specs. If the OPC foundation was *really* interested in protecting quality and determining commitment, having an email address that can get by OPC's download security system (or $2,500 cash lying around to purchase a corporate membership) should not be the determining factor in who is viewed as a competent developer of quality software. |
|
| Back to top |
|
|
Fred_Loveless
Joined: 26 Aug 2005
Posts: 168
Location: Portland, Maine
|
| Posted: Wed May 07, 2008 5:19 pm Post subject: |
|
|
I have kept my 2 cents out of this until now but wanted to make a comment. Until moving to a new position I managed the support department at Kepware. I cannot begin to tell you the number of issues that we had to resolve that were result of customers buying poorly designed products. Every time OPC or our server was blamed until we provided proof otherwise. Sometimes this was easy to do and sometimes it took a lot of manhours that could otherwise have been used more productively. That is not to say that we write perfect code. All products have bugs.
Once the OPC Foundation restricted access to the specs and toolkits these problems started to go away. I am a programmer and I would love to see all the OPC Standards freely accessible. The cruel reality though is that for every programmer out there that writes clear well formed and intelligent process code there are 5 that want to take the easy way out which is never the best way.
One other comment this is not share ware and the OPC Foundation provides a lot of services that are funded by fees that are paid.
Fred Loveless |
|
| Back to top |
|
|
|
