Unlocking the Power of .NET for Industrial Automation
Industrial application developers have had two main options for interacting with production processes via programmable logic controllers (PLCs): they can buy a preprogrammed monolithic, shrink-wrapped human machine interface (HMI), complete and ready to go or they can customize their own solutions.
Shrink-wrapped HMI software packages are appealing because many complex tasks are hidden from you. Purchase the development software from an authorized distributor, load it into your development PC and then configure, debug and test. Then, just deploy the necessary runtime applications, data servers and configuration files on to your target PC or PCs. What could be easier?
But cookie-cutter HMI software solutions might not necessarily be the best or most practical approach for your specific industrial applications.
For one thing, while the shrink-wrapped HMI software packages enable connections to other vendors' devices, software, and systems via OPC or other standards, such connectivity is seldom adequate for high security or real-time control. And no matter how advanced the integration technology the package uses, you will end up lagging behind the technology curve. For example, if you had bought a package using the distributed common object model (DCOM) and wanted to benefit from advances in security and robustness that Microsoft had made since you bought the package, you would have to buy a new package. Moreover, the monolithic nature of the shrink-wrapped offerings often makes it difficult to embed third-party capabilities directly into your solution, thus limiting your options further.
Then there's training. Because the development environment and behavior of each HMI vendor's software varies, you'll need to acquire specialized skills to accomplish similar tasks. Training courses, material costs and schedules also vary by HMI publisher and many times are offered only through exclusive distributor channels. You could consider hiring outside help, but because of the specialized training and experience, the talent pool can be relatively shallow and therefore proportionately expensive.
And for many, cost of multiple deployments is an even bigger issue. Before you can actually deploy your solution to PCs, portable devices, or Web servers, you must typically have to pay for additional runtime software licenses. If you have more than a couple of users, this could amount to a considerable expense, often making this approach cost-prohibitive, especially if you are paying for more functionality than you actually never need.
Finally, there are the intangibles. As well-designed and flexible as these shrinkwrapped solutions might be, they almost always force compromises that would not be necessary if the solution were custom built for your specific applications. Whether that is a matter of function or just pride, it can be significant determining your satisfaction with the resulting interface.
Author: INGEAR | File Type: PDF