Siemens Launches New Information Link Between PLC And PC

<%=company1%> has introduced SIMATIC Computing, a cost effective data link for users to manage data between PLCs and PCs. Industrial Software Business Unit of Siemens Energy & Automation describes SIMATIC Computing as a new product category called business integration tool, "to directly view, modify, and collect process data via standard applications or the Internet."

This software application accesses data from Siemens' SIMATIC S7 PLCs or PC-based WinLC controller using three core components based on Microsoft's proven OLE technology: ActiveX controls, Tagfile Configurator and OPC server.

An integrated ActiveX Container called "SoftContainer" includes controls for displaying and modifying PLC data without having to write code in a high level programming language. The same ActiveX controls can also be integrated in any OLE capable application like Visual Basic, Visual C++ or Excel. The physical link for accessing data is via MPI, Profibus or Industrial Ethernet.

The Tagfile Configurator allows the use of symbolic names defined in the SIMATIC STEP 7 symbol table. STEP 7 is the Siemens unified development software tools to configure, manage and maintain a plant-wide automation system. Using symbolic names instead of absolute addresses to access process data facilitates access to the PLC data. The symbols are stored in a tag file, which is created automatically from the symbol table of the STEP 7 project. Multiple STEP 7 programs can be mapped into a single tag file, with each program providing access to a different computer and PLC. This method allows the user to access data from different computers and PLCs simultaneously.

An OPC (OLE for Process Control) server in SIMATIC Computing provides a standard mechanism for communicating to numerous data sources, whether they be the devices on the factory floor or a database in the control room. Any OPC client application has access to data in the hard PLC or soft PC controller. The OPC server's "plug and play" capability allows the use of off-the-shelf tools (such as SCADA packages or databases) to assemble a system without having to worry about drivers or interfaces.

Edited by Stephen Heiser