|An alarm is related to any abnormal situation on the equipment that may endanger people, equipment, or material being processed" [SEMI E30, 2]. GEM allows the host to be notified when alarm conditions are detected and cleared.
|A collection event is a "detectable occurrence significant to the equipment" that "is considered to be significant to the host". [SEMI E30, 2] GEM allows the host to be notified when a collection event occurs. This allows the host to track the equipment's activity.
|Data variables "…may only be valid upon the occurrence of a particular event". [SEMI E5, 6.6]. The host can gather data variable values from the GEM Equipment. The data variable values provide information specifically related to the event.
|Equipment Constants are "settable by the Host"[SEMI E5 6.6]. The host can gather equipment constant values from the GEM Equipment. The host can also set equipment constant values on the GEM Equipment to control the equipment's behavior.
|An "intelligent system which communicates with a host" [SEMI E4, 2.1] and complies to the SECS/GEM standard.
|"An intelligent system which communicates with the equipment." [SEMI E4, 2.1]. The host can be viewed as a line management system. GEM does not intend to define how the host should behave. The GEM SECS standard defines the set of messages a host must use when interacting with GEM Equipment. A GEM Equipment can communicate with one host. A host can communicate with multiple GEM Equipment.
|SEMI standard High Speed Message Service-Single Session which defines TCP/IP network communication used by SECS/GEM for host/equipment communication. It is replacing the SECS-I standard. Only one client host can use a specific port at a time.
|GUIDE FOR PV EQUIPMENT COMMUNICATION INTERFACES (PVECI), based on SECS/GEM, specifically for photovoltaic equipment suppliers.
|A Recipe (see Recipe)
|A set of instructions for the equipment.
|"A set of variables predefined by the equipment or defined by the host…". The host uses reports to gather status variable, data variable, and equipment constant values. The host can request a report explicitly or attach a set of reports to a collection event.
|"Status variables may include any parameters that can be sampled in time such as temperature or quantity of a consumable." [SEMI E5, 6.5] "Status values … always contain valid information." [SEMI E5, 6.6]. The host can gather status variable values from the GEM Equipment.
|SEMI Equipment Communications Standard 1 Message Transfer - defines RS-232 serial communication used by SECS GEM for host/equipment communication. It is phasing out due to inherent speed limitations. It is being replaced by the HSMS standard.
|SEMI Equipment Communications Standard 2 Message Content. SECS GEM is a specific implementation of the SECS-II standard. SECS-II defines most concepts and functionality used in the SECS/GEM standard. Many SECS-II capable systems are not GEM compliant.
|All GEM Equipment and host communication is accomplished using SECS-II messages. Each unique SECS-II message is identified by its stream number (S) and function number (F). The SECS-II standard defines a large set of SECS-II messages determining each one's purpose, content, and usage. The SECS GEM standard defines how to use a subset of these SECS-II messages yet allows other SECS-II messages to be used in addition to this subset.
To learn more about SECS Messaging, download the primer.