Tag Archives: copyright

Intellectual Property and Control System Integrators

I’m not a lawyer and what follows is not legal advice. What I’d like to do here is point out some minimum things that you need to be aware of if you’re doing control system integration when it comes to intellectual property. I hope you can appreciate that there are subtle details that can affect the reality of your situation and you should consult a lawyer depending on your situation, geographic location, and product.

If you do control system integration for a living then you deal every day with intellectual property. Ladder logic (or structured text, etc.) is code, and code is automatically copyrighted. Electrical designs are also intellectual property. The important thing to realize is that somebody owns that intellectual property, and people are sometimes surprised by who owns it.

Here’s a typical situation: you work for a control system integrator and they’re doing a fixed price (or “turn-key”) project for a customer. In this case the ownership of the copyright should be spelled out in the contract, and most control system integrators will specify that the copyright belongs to the integrator, but part of the purchase price of the project covers a license to use that software in their facility. There are very good reasons for this. The integrator works on many different projects for many different customers and over time you’re going to see the same problem over and over so you want the ability to maintain an internal library of tested code that you can re-use on future projects. Not only does this make you more efficient, but it’s almost impossible to avoid writing the same code again when you see a problem that you’ve solved before.

In this case the customer, to protect themselves, needs to insist on a license that will cover all of their needs, including the ability to see and modify the code, including having someone else come in and modify it, though only for use in that facility or on that machine, as the case may be.

Now consider a very different situation. You’re a control system integrator doing a time-and-material project for a customer. They have their own internal PLC ladder logic standard, including a library of function blocks, and they know how they want everything written. They give you a sample program and tell you to start with that and modify it to suit the machine you’re building. This is a completely different case. The copyright of the finished PLC program is almost certainly owned by the customer, not the integrator. The integrator and the customer should both be making sure that the contract specifies this in writing. This creates some interesting differences for the integrator.

The integrator cannot (and should not) be using their own internal library of code on this project, or the customer could end up claiming copyright on the integrator’s code. Even more importantly, the integrator should definitely NOT take code they see in the customer’s standard library and put it in their own internal library. Here’s what could happen: you take code from customer A and put it in your library. You use that code on a project for customer B, and it happens that customer B is a competitor to customer A. Customer A’s lawyers can now use the legal system to prevent customer B from using that machine without paying royalties to customer A.

You may be wondering, “how would customer A even find out that this happened?” There are several ways… for one, people in the control system industry move around. A lot. Trust me, it’s a small group of people and everybody knows each other. It’s not a big stretch for someone who worked at customer B to end up at customer A. For another, sometimes employees just talk. I’m writing this because just the other day I witnessed an employee from a local integrator say out loud that they’d done just this… took some function blocks from their customer and used it on other projects for other customers… and they said this in front of the customer they took them from! Now, the representative from the customer seemed to think this was OK, but I doubt their corporate lawyer would agree, and I doubt this agreement was in writing. If some future customer of the integrator ever got in trouble legally, what do you think would happen to that integrator?

I realize it’s sometimes hard to adjust from a university environment with the free flow of ideas, where everyone’s downloading copyrighted movies and songs from peer-to-peer networks all day long, and then work in a corporate environment where the stakes are much higher, where lawyers and executives on both sides would love to find some leverage over their competition. Seriously, it’s not worth your career. Take a moment to school yourself on intellectual property law and how it affects your profession. This can be a big deal. Be careful.

A Very Fast Tutorial on Open Source Licenses

I’ve written a bit of open source software lately, and I did a lot of learning about open source licenses. Unfortunately, after you learn a lot about a topic, you tend to subconsciously assume everyone knows what you do. In the interest of catching you all up, here’s a cheat sheet with some practical tips:

Note: I use the terms “proprietary” and “commercial” with specific meanings. “Commercial” means an application that isn’t open-source and you sell copies of it for money. “Proprietary” includes “commercial” but also includes software that is only used internally, never sold.

BSD or MIT/X11 Licenses

Sometimes called the “Academic” Licenses

Technically it’s the “revised” BSD license, but it’s been around so long that it’s just the BSD license now. It’s pretty much equivalent to the MIT/X11 license. These are considered to be the least restrictive, “do-anything-you-want” licenses as long as you keep the original notice on the code, display the copyright notice in your program, and don’t infer the author is endorsing your product. Also, it has a disclaimer saying they’re not responsible for anything you do with it. Standard stuff.

You can use this code in proprietary software, and you can use it in a GPL’d work (the common term for this is “GPL-compatible”.)

Apache 2.0

The Apache 2.0 license is similar in use to the BSD license, but it adds a patent grant. That is, it specifically states that if the authors hold any patents that cover the code, you can still use this code and be safe from that. Some might argue that BSD implies the patent grant, but it’s not specific, so Apache 2.0 makes it specific.

You can use it in proprietary software, and it is GPL-compatible, but only with version 3 of the GPL.

Mozilla Public License 1.1 and the Common Development and Distribution License

a.k.a. MPL 1.1 and CDDL

CDDL was based on the MPL 1.1.

These are your “weak copyleft” licenses, copyleft meaning some part of the derived work also has to be released under the same license. What it means is that you can use this code in a proprietary application, but if you make any changes to the code you included, you have to release that code publicly (but not the code of your entire work). The CDDL defines the boundary at the source file, so if you change one of the original files, you have to release that back.

These are not compatible with the GPL.


Microsoft Public License

You’ll see this license a lot if you do much .NET coding. A lot of the stuff you find on MS’s open source site, CodePlex, is MS-PL licensed. The short of it is that you can use it in proprietary applications, but it’s not GPL-compatible (by design – MS hates Linux). It’s also not copyleft at all.


Your strong copyleft

The GPL is the one everyone loves to hate, but it’s also popular because the Linux kernel is released under the GPLv2 license, and many/most of the tools of the Linux community are GPL-based.

Unlike the previous licenses, if you take any code from a GPL’d program and include it in your own project, you’re making a “derived work” and you must agree to release your entire derived work under the same license (or a later version if the author specifically says you can). That means you can’t use GPL’d code in your commercial application (but you can use it in internal applications).

The reason some programmers are so annoyed by it is that they’re at work Googling for some code to solve their problem, realize someone has written an open source library to do exactly what they want and they get all excited. Then they check the license and their heart drops because it’s GPL and they realize they can’t use it. A small minority go as far as to send hate mail to the author. (As someone who has released some GPL’d code, I’ve received my share of this hate mail, and I find it very silly. I’m offering something for free, under certain conditions, and you are free to take it or leave it.) What most programmers don’t seem to understand is that if you email the author, they’d probably be willing to sell you a commercial license for the code so you could use it in your program.


The weak copyleft version

The “L” originally stood for library, but now it stands for “lesser”. It kind of works like the CDDL, but it defines the boundary at the “library” rather than the source file. It basically says you can use this library, even in a commercial application, but if you make any changes to it, you must release your new version of the library under the same (or newer…) license.

It also adds a restriction that some people overlook – you must also provide the users of your application the ability to replace the LGPL’d library with a newer or modified version of that library. Usually this means providing the binaries and compilation instructions. Consider the difficulty of meeting this obligation if your derived work is firmware on an embedded device. Version 3 of the GPL and LGPL make it very clear that you must allow your users all the tools needed to replace the software on the device. This was a reaction to the TiVo, which used GPL’d code, and released the code publicly, but didn’t allow anyone to further modify the code and update their TiVo’s with it.

The other thing you have to worry about is copying code. If you copy any code from the library into your main project, then your project becomes a derived work, and you’re essentially forced to release your whole application under the LGPL. Programmers don’t worry about this too much, but legal departments do.



It turns out you can take GPL’d code, run it on a server as a web application, make all the changes you want, and never release your code because you’re not “distributing” the derived work, and distribution is what triggers the GPL. (Google has it’s own version of Linux that it never had to release because it only uses it internally).

This ticked off some people who were writing GPL’d blogging and other website type software, so someone came up with the AGPL. This changes the triggering clause, so if you are using the AGPL’d code in a website, you have to make any changes public.


Those are the major licenses you’ll run into. If you’re writing commercial software, you want to look for BSD, MIT/X11, Apache 2.0, MS-PL, MPL 1.1 or CDDL code. You can also use LGPL’d code, but watch out for the extra restrictions.

If the proprietary software you’re writing is only for internal use, or you’re writing it “for hire” for another company that will only use it internally, then you’re safe to use GPL’d or LGPL’d code because you won’t trigger the distribution clause. Just be sure that you make this clear to your management/customer before you go down this path. If they decide they want to sell the software later, they’ll have a mess to clean up.

If you’re writing open source code then you need to pick a license. A BSD license is the easiest, and it’s great for little utility libraries because anyone can use it. If you’re writing an application and you want to protect against some company taking the application, adding a bunch of new features that make it incompatible, and then releasing and charging for it without ever giving you anything, then you should choose the GPL (or AGPL if it’s a web application).

Format Shift

In case anyone out there is doubting my absolute nerdiness, I currently have a VCR hooked up to my computer through an NTSC to USB converter and I’m converting my old VHS copy of Hackers to an mpeg so I can store it on my Windows Home Server and stream it to my TiVo. Any other pseudo-nerd would just use BitTorrent to download a pirated copy of their favorite movies from the internet, but I’m one of those crazy people who think that copyright serves a purpose. At the same time, I absolutely stand behind my right to format shift the digital content I’ve already purchased to new formats.

“Of all the things I’ve lost, I miss my mind the most.”

That’s my rant on format shifting. Interested in robot shifting? Check out Robot Shift – make the move to industrial robots.