EDA/Interface A and SECS/GEM

Mapping EDA/Interface A to SECS/GEM 

EDA (Interface A) uses many of the same concepts as SECS/GEM. Here is a mapping between the similar concepts and technologies.

SECS/GEM EDA/Interface A
Status Variables, Equipment Constants, and Data Variables Parameters
Alarms Exceptions
Collection Events (S6, F11) Events in DCP
E39 Objects SEMIObjType and Instance IDs
Trace Data Collection Traces in DCP
Reports Data Collection Plans/Reports
State Machines State Machines
Enable/Disable Collection Events ActivatePlan/DeactivatePlan
Define and Link Reports (S2, F33 and S2, F35) DefinePlan


Comparing EDA/Interface A With SECS/GEM

SECS/GEM EDA/Interface A
SECS/GEM supports only one client connection. IC makers cannot run several data gathering applications at the same time without an infrastructure to share the data. EDA requires support for multiple concurrent clients.
SECS/GEM is only partially self-describing and therefore relies on good documentation. IC makers have complained that the documentation is often not well-maintained. EDA is self-describing through the E125 standard's metadata.
SECS/GEM data is relatively flat and unorganized. The IC Maker must study the documentation, hardware, software, and processing to understand how to organize the data. EDA presents the data in a hierarchy, organized by the major hardware components.
Data in a SECS/GEM message is highly structured and relatively inflexible. Because EDA uses XML, it is inherently designed to accommodate additional metadata.
SECS/GEM is used extensively in only a few industries, which limits the number of experts in the world. SOAP/XML and HTTP are the backbone of most Internet and Intranet applications. There are many programmers worldwide that are familiar with this technology.
In most factories, the SECS/GEM interface is used for equipment configuration and control, and therefore subject to extensive oversight and lengthy change procedures. It can take at least several weeks for any data collection changes to be implemented. EDA is independent of the GEM interface and therefore immediately available for the dynamic data collection needs of the process engineers.