Free OPC SERVER
Advosol offers a number of simulation and sample servers, usually as part of a toolkit or component evaluation (requires registration). Supported specifications include DA 2, DA 3, HDA and XML-DA.
Freeware simulator server for DA 2.0 and 1.0. Usefully shows list of clients and groups, plus an activity log.
Evaluation version of a combined OPC server and client package, including several I/O drivers. Very flexible, but user interface is sometimes confusing. Includes support for a proprietary protocol, offering a subset of OPC Data Access functionality, which uses XML data packets sent over HTTP.
Time-limited demo download of leading DA server bundle, incorporating over 80 communications drivers. Supports DDE and SuiteLink for legacy applications. Also includes a useful client program (see clients). Now DA 3.0 compliant.
Various MatrikonOPC servers are available as free time-limited downloads, requiring restarting after two hours continuous use. All MatrikonOPC servers also have a DDE server capability.
Free demo server. Version 4.10 adds XML-DA to the existing DA and AE support. The XML-DA server may run standalone, or integrated with Apache or IIS.
OPCSvr.zip is a simulation server supporting Data Access 2. It has some useful diagnostic aids: the user may control the profiles of the simulated data points, and all OPC interface calls are displayed in a logging window. Also available is a demo server for Historical Data Access.