Some automation projects require specialized machinery or other equipment with built-in control systems. Specialty machine builders and OEMs generally perform the software and hardware integration for the custom equipment they fabricate. Some machine builders may also integrate their custom control systems into the overall plant control system. Many system integrators, machine builders, and OEMs maintain their own in-house panel shops. They may use their own software products or specialize in configuring commercial software packages.
Many software houses are also value-added resellers.
The value they add may be other compatible products or services such as software configuration, troubleshooting, or complete system integration. VARs generally focus on a particular vendor's products or a particular industry's applications. VADs also maintain product inventories and provide technical advice. Other vendors have gotten into the system integration business as a matter of necessity. The advent of digital drives has enabled a host of advanced motion control functions.