一、概述
SECS/GEM是由國際半導體設備與材料協會（SEMI）制定的連接性標准。此連接性標准用於在設備和工廠的資訊和控制系統間建立通訊。SECS是SEMI設備通訊標准的縮寫。GEM指SEMI連接性標准E30，被定義為制造設備實現通訊和控制的一般模型。一般來說，SECS/GEM標准定義了信息、狀態機和情境，來讓工廠軟件能夠控制並監視制造設備。正式名稱是SEMI連接性標准E30。
在實現SECS/GEM標准的工廠內，存在主機和設備這兩方。由設備在其中一台必須實施和遵守SEMI E30標准的計算機上運行軟件。由制造商（工廠）運行與設備接口建立通訊的主機軟件。主機無需遵守完整的連接性標准，因為它只設定設備的預期行為。不過，若要使用接口，主機必須進行主機端通訊。SECS/GEM為每條可能的主機信息設定了清晰的設備預期行為。
通訊
SECS/GEM SEMI連接性標准定義了主機和設備開始建立通訊的方式，並且還定義了當通訊中斷時重新建立通訊的方式。在線識別方法負責驗證設備的硬件和軟件標識。終端服務功能允許主機操作員和設備操作員在控制台上交換手動輸入的文本。
控制
SECS/GEM SEMI連接性標准概括了主機與設備操作員之間的合作等級的控制狀態模型。設備提供三種基本的主機控制等級：離線，在線/本地，以及在線/遠程，確定了主機控制和監控設備的能力。設備操作員設定主機控制的等級。遠程控制功能允許主機發送諸如“啟動”、“停止”、“暫停”、“繼續”和“中斷”這樣的指令，用以控制設備的工作過程。
運作通知
收集事件和警報功能使主機能監控設備的運作情況。設備收集事件功能會將重要的正常活動和異常活動通知主機。當潛在的危險活動出現並隨后被清除時，設備警報功能會通知主機。主機設定哪些收集事件和警報需要通知。SECS/GEM連接性標准要求特定的事件必須有通知，但一般會給設備定義額外的事件，以便主機監控具體設備相關的活動。
二、基本術語
| Term | Description |
|---|---|
| Alarm | 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. 設備處於非正常運行，可能危害操作員、設備或無聊的情況下，GEM允許當檢測到告警或清除告警后通知host主機。 |
| Collection Event | 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. 對於設備而言是可檢測的事件信號。 |
| Data Variable | 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. 針對某一特定事件才有效。主機能獲取某一事件所有的數據變量值。 |
| Equipment Constant | 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. 可被主機讀取或設置的設備特性數據。 |
| GEM Equipment | An "intelligent system which communicates with a host" [SEMI E4, 2.1] and complies to the SECS/GEM standard. 就是一個遵循SECS/GEM協議標准，並能與主機進行通信的設備系統。 |
| Host | "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. 就是一個線性控制系統（系統當然包含了依附在硬件上的軟件） |
| HSMS-SS | 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. 在SECS/GEM標准中通過定義TCP/IP網絡通信協議在單客戶端-主機的情況下使用指定端口下可替換SECS-1。 |
| PV2 | GUIDE FOR PV EQUIPMENT COMMUNICATION INTERFACES (PVECI), based on SECS/GEM, specifically for photovoltaic equipment suppliers. |
| Process Program | A Recipe (see Recipe) |
| Recipe | A set of instructions for the equipment. |
| Report | "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. 就是應答。 |
| Status Variable | "Status variables may include any parameters that can be sampled in time such as temperature or quantity of a consumable（消耗品數量）." [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. 狀態變量/數據 |
| SECS-I | 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. 現階段由於自身速度的限制，已逐步被HSMS標准替代。 |
| SECS-II | 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. |
| SECS-II Message | 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. |