It is important that a MES software stores data with timestamps in UTC and not in local time. The problem are daylight savings applied to local time in many countries, including EU: In Spring, you have a gap of one our in your datastream, in Autumn you loose data of 1 hour ( as it is not possible for most MES systems, to store 2 datasets with the same timestamp ).
Experts told me about a weakness of OPC servers: All the data an OPC server gets is provided / pushed to process visualisation systems. It is one of the major tasks of a process visualisation system, to filter the incoming information ( by checking the OPC tags ), to reduce the data to an amout
which can be handled by the process visualisation display.
SEMI Interface A Standards ( E120, E125, E132, E134 ).
EDA does not replace the SEMI SECS/GEM standards or the SEMI GEM 300 standards, since EDA does not provide any features for equipment control or configuration. Instead, equipment suppliers support EDA in addition to other required interfaces.
The Generic Equipment Model ( GEM ) defines a standard implementation of SECS-II for all semiconductor manufacturing equipment. The GEM standard defines a common set of equipment behavior and communications capabilities that provide the functionality and flexibility to support the manufacturing automation programs of semiconductor device manufacturers.
The PEER Group Inc. "SDR" - “Provides high-technology factories and their equipment suppliers with the connectivity solution required to implement the well established SEMI equipment communication standard (SECS). SDR is fully compliant with current releases of SEMI standards E4 (SECS I), E5 (SECS II) and E37 (HSMS) and is in wide use throughout the semiconductor industry and is considered the standard that other SECS implementations are measured against.”.
The PEER Group Inc. "GEM4Tools" - “SECS/GEM is the communications standard for high-technology equipment. OPC is the communications standard for PLC-based equipment. PEER Group brings SECS/GEM and OPC together to deliver fast and easy factory communications for semiconductor, solar, MEMs, LED and other high-technology manufacturing equipment”.
The PEER Group Inc. "SECS4Hosts" - “The SECS/GEM protocol is complicated compared with PLC-based factory communications. With SECS4Hosts, you can simplify the development of a host-side SECS or SECS/GEM driver. SECS4Hosts is all about speed. It's simply the fastest way to give your Windows host applications the ability to communicate with any SECS-compliant equipment”.
EN.Wikipedia "SECS-II" - “The protocol is maintained by the SEMI organization, from which copies of the SEMI E5 standard may be obtained for a fee”.