SIS系統(tǒng)技術說明書

SIS System Technical Specification

1、概念/Concept

SIS是安全儀表系統(tǒng)，根據(jù)美國儀表協(xié)會（ISA）對安全系統(tǒng)控制系統(tǒng)的定義而得名。也稱緊急停車系統(tǒng)（ESD）安全連鎖系統(tǒng)（SIS）或儀表保護系統(tǒng)（IPS），安全儀表系統(tǒng)是指，能實現(xiàn)一個或多個安全功能的系統(tǒng)。用于監(jiān)視生產(chǎn)裝置或獨立單元的操作。如果生產(chǎn)過程超出安全操作范圍，可以使其進入安全狀態(tài)，確保裝置或獨立單元具有一定的安全度。安全系統(tǒng)不同于批量控制、順序控制及過程控制的工藝連鎖。當過程變量（溫度、壓力、流量、液位等）超限、機械設備故障、系統(tǒng)本身故障或能源中斷時，安全儀表系統(tǒng)自動（必要時可手動）的完成預先設定的動作，使操作人員及工藝裝置處于安全狀態(tài)。SIS系統(tǒng)可用來實現(xiàn)一個和多個安全儀表功能的控制系統(tǒng)。主要為工廠控制系統(tǒng)中報警和聯(lián)鎖部分，對控制系統(tǒng)中檢測的結果實施報警動作或調(diào)節(jié)或停機控制，是工廠企業(yè)自動控制中的重要組成部分。

SIS is a Safety instrumented system, named after the definition of the safety system control system by the American Instrument Association (ISA). Also called emergency shutdown system (ESD) safety interlocking system (SIS) or instrument protection system (IPS), Safety instrumented system refers to a system that can realize one or more safety functions. Used to monitor the operation of production devices or independent units. If the production process exceeds the safe operating range, it can be put into a safe state to ensure that the device or independent unit has a certain degree of safety. The safety system is different from the process interlocking of batch control, sequence control, and process control. When the process variables (temperature, pressure, flow, liquid level, etc.) exceed the limit, mechanical equipment failure, system failure or energy interruption, the Safety instrumented system automatically (manually if necessary) completes the preset action, so that the operators and process devices are in a safe state. The SIS system can be used to implement a control system for one or multiple safety instrument functions. Mainly for the alarm and interlocking parts of the factory control system, implementing alarm actions or adjusting or stopping control on the detection results in the control system is an important component of automatic control in factories and enterprises.

2、系統(tǒng)構成/System composition

2.1、安全儀表系統(tǒng)主要包括測量單元、邏輯控制單元和執(zhí)行單元，再配合相應的軟件組成。通常與基本過程控制系統(tǒng)（如：DCS系統(tǒng)）有通訊要求，共同組成生產(chǎn)裝置的過程儀表控制系統(tǒng)。

The Safety instrumented system mainly consists of measurement unit, logic control unit and execution unit, together with corresponding software. Usually, there are communication requirements with the basic process control system (such as DCS system), which together form the process instrument control system of the production device.

2.2、安全完整性等級/Safety Integrity Level

安全完整性等級是一種國際通用的“標準語言”，目的是用一種簡單的方法來劃分工藝裝置中每個安全儀表回路的安全等級要求。是SIS系統(tǒng)設計中必須遵從的一個重要安全指標。

依據(jù)IEC標準由低到高劃分為SIL1-SIL4， ISA 84.01標準劃分為SIL1-SIL3，DIN V VDE0804標準由低到高劃分為AK1-AI8，它們之間的對應關系如下。

Safety integrity level is an international "standard language", which aims to divide the safety level requirements of each safety instrument loop in the process unit in a simple way. It is an important safety indicator that must be followed in the design of SIS systems.

According to the IEC standard, it is divided into SIL1-SIL4 from low to high, SIL1-SIL3 from ISA 84.01, and AK1-AI8 from low to high according to DIN V VDE0804. The corresponding relationship between them is as follows.

安全完整性等級/Safety integrity level

2.3、安全生命周期/Safety Lifecycle

安全儀表系統(tǒng)的安全生命周期也是一個非常重要的概念，要保證工藝裝置的安全生產(chǎn)運行，不但要選擇合適的控制系統(tǒng)，而且對工藝過程的風險評估、安全回路等級劃分和控制系統(tǒng)的維護管理也有嚴格要求。SIS系統(tǒng)的整個安全生命周期可分為分析、工程實施及操作維護3大階段。在分析階段，要辨識工藝過程的潛在危險，并對其后果和可能性進行分析，以便確定過程風險及必要的風險降低要求。工程實施階段主要完成SIS的工程設計、儀表選型，安全邏輯控制器的硬件配置、軟件組態(tài)以及系統(tǒng)集成，完成操作和維護人員的培訓，完成SIS的安裝和調(diào)試，以及SIS的安全驗證。操作維護階段在整個安全生命周期中時間區(qū)間最長，包括操作和維護、修改和SIS的停用。

The safety life cycle of the Safety instrumented system is also a very important concept. To ensure the safe production and operation of the process unit, not only the appropriate control system should be selected, but also there are strict requirements for the risk assessment of the process, the classification of the safety loop, and the maintenance and management of the control system. The entire safety lifecycle of the SIS system can be divided into three stages: analysis, engineering implementation, and operation and maintenance. In the analysis stage, potential hazards of the process should be identified, and their consequences and possibilities should be analyzed to determine process risks and necessary risk reduction requirements. During the implementation phase of the project, the main tasks are to complete the engineering design, instrument selection, hardware configuration, software configuration, and system integration of the SIS, as well as training for operation and maintenance personnel, installation and debugging of the SIS, and safety verification of the SIS. The operation and maintenance phase has the longest time interval throughout the entire safety lifecycle, including operation and maintenance, modification, and SIS deactivation.

在SIS系統(tǒng)設計選型后，要根據(jù)可靠性數(shù)據(jù)和操作模式，對安全儀表功能的危險失效概率或危險失效頻率進行計算，評定是否滿足目標安全儀表的功能安全要求。這是保證必要的風險降低和功能安全儀表功能安全的重要環(huán)節(jié)。同時，在SIS運行后，日常維護、修改管理、周期性檢驗測試、功能安全審計等也是功能安全的核心工作。

After the design and selection of SIS system, the dangerous failure probability or dangerous failure frequency of safety instrument function shall be calculated according to the reliability data and operation mode to assess whether it meets the Functional safety requirements of the target safety instrument. This is an important link to ensure necessary risk reduction and Functional safety and Functional safety of instruments. At the same time, after SIS operation, routine maintenance, modification management, periodic inspection and testing, Functional safety audit, etc. are also the core work of Functional safety.