There is a truism that large companies cannot innovate. When Invensys introduced InFusion, though, then Wonderware CEO Mike Bradley pointed me to Geoffrey Moore’s book, “Dealing with Darwin.” Moore discusses a method of thinking through which corporate managers can foster innovation while maintaining legacy business. That’s what the managers at Invensys and Wonderware believed they were doing.

Recently, however, I’ve run across several examples that point to the difficulty for large companies to innovate.

In an interview with Moira Gunn on TechNation, Vijay Vaitheeswaran, author of “Need, Speed, Greed,” stated that many innovations are small, “some of the best ideas are small in implementations.” The ramifications in our business are that large companies require a large market to justify the investment. Picking up an additional $5 million to $50 million in sales matters not so much to a $5 billion company. It needs $500 million or more to make a dent in the amount of additional revenue necessary to grow by ten percent. But to a $5 million company growing to $10 million is fantastic.

Later, Gunn interviewed ACP ThinManager conference. This is an example of a small company that weathered the downturn with strength on the innovation of a different way to do HMI/SCADA. Opto 22 is an example of a small company that isn’t afraid to try things. It’s often at the cutting edge of morphing IT and control–and in its latest iteration is doing much with energy management. Two small companies are attempting to disrupt the HMI/SCADA from a different direction–through the cloud: Inductive Automation and Tatsoft.

I’m very interested in hearing from small companies trying some innovative ideas. The big companies (mostly) have big PR budgets to make sure they are in front of editors. But everyone at small companies has an email account or twitter feed or can comment on blogs (hint). What’s happening?