Discussion on the differences and connections between ESD and SIS

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I saw a good post and would like to share it with everyone [Repost]: To give just an example – it may not be appropriate, but it can help in understanding these concepts. Siemens’ PCS7 system. It includes S7-400H hardware, WinCC monitoring software, and Simaticnet communication software. Step7 programming software. Intelligent metering tools such as PDM. PCS7 is a combination of software and hardware, and it represents a conceptual system. The principle is basically the same for SIS as well. Essentially, the hardware system of SIS includes not only the SIS controller and IOs (such as Triconex, HIMA, Siemens 400FH). It should also include all other input components that interface with the controller, such as sensors, transmitters, and detection devices that have obtained TUV SIL certification ； It should also include all output components, such as actuators that have obtained TUV SIL certification (hydraulic safety actuators, pneumatic safety actuators, electric safety actuators), as well as certified field devices. -- In strict-demand sites, the valve body must also come with a TUV certificate. For example, the safety valves in nuclear power plants must not only meet the quality standards for boilers and pressure vessels, but also come with nuclear inspection certificates as well as TUV safety certification, clearly indicating the SIL level. So, let’s understand these concepts again: a safety controller (this is the most scientific term used currently) is merely one component of the hardware in an SIS system. Manufacturers of safety controllers include Triconex, HIMA, Siemens, Moore, ICS, ABB, Emerson, and others. These safety controllers are used in emergency stop applications, and are referred to as ESD. Fire detection and gas alarm systems used in oil and gas fields are referred to as F&GS. Combustion control systems used in hazardous environments are called BMS. ESD, F&GS, and BMS do not refer to Triconex, nor to HIMA, and certainly not to the controllers produced by these manufacturers. Rather, the safety controllers made by these manufacturers are used in various different scenarios and serve different purposes, which is why they have different names. – Next time, when someone asks you why Triconex is called ESD at times, PSD at other times, F&GS at yet other times, and BMS again at different times, answer them. It is also called SIS. . . You should understand its meaning. These are all safety controllers, or safety control systems; in IEC standards they were formerly referred to as safety systems (PES), that is, safety-oriented electronic devices. When used in contexts referred to as ESD, it is ESD; when used in contexts referred to as F&GS, it is F&GS. Meanwhile, SIS is a complete, systematic concept. As can be seen from its name, it is a complete concept, one that places more emphasis on wholeness, a system. Overall safety is built upon various security mechanisms, including safety controllers (such as ESD, F&GS, BMS, etc.), safety-rated instruments, safety-rated actuators, safety-rated software (function block libraries, interlock specifications), and even \"safe communication functions\" (which are rarely used these days). The holistic concept of SIS should also include standards that apply throughout the entire lifecycle of the safety control system, such as the initial design, the construction phase, and commissioning ； Final trial operation, evaluation, and verification. Subsequent maintenance. Dismantling before the end of the safety lifecycle. . . In short, the concept of SIS is very comprehensive and extensive. – The first to get confused is always the design institute, and then the design institute confuses the client as well. . . Then many people who work on SIS and adjust ESD, having done it for several years, are also a bit confused about the concepts. Why is the concept of SIS mentioned more often in tenders these past few years? Theoretically, only ESD “does not necessarily” constitute a complete SIS control system. ESD is just one component of SIS, and it is located in the physical hardware; it is the most important component among them. Therefore, many people believe that SIS is the same as ESD. . . ESD is SIS. With ESD, there are also many surrounding supporting devices. A SIS control system can then be formed. What users want is a complete security control system; that’s why the bidding specifications over the past few years have all been referred to as SIS, haha. To be honest, it’s still the same old approach, but at least it shows that our users have made progress in terms of their overall understanding of security – whether through being misled or through their own efforts, progress has been made regardless. Similarly, (I once heard from a deputy sales manager at a well-known DCS company that Siemens’ PCS7 DCS is actually the S7-400 PLC, and the S7-400 PLC is in turn the PCS7 DCS; haha) many things are not simply equivalent to each other! ITCC. Control of high-speed rotating equipment, such as steam turbine unit control, air compressor control, and blast furnace blower control. Even turbine engine control, gas turbine control. It’s a different concept. For example, Triconex controllers can perform ITCC in addition to ESD and F&GS functions. Systems such as ESD, F&GS, and those falling under the SIS concept require certification, and a SIL rating certificate from TUV is essential. For ITCC, a TUV certification is not mandatory. The same item from the same manufacturer can have different uses in various situations, which is why it has different names. By the same logic, if you have a great deal of money, you can use the Triconex system for PLCs, or for small DCS systems. At this point, you can still refer to Triconex as a PLC or a DCS – either term is acceptable. CCC focuses on ITCC, not ESD ； Yokogawa and Emerson’s safety systems are basically designed for ESD and F&GS only, without ITCC functionality. Triconex handles both ESD and ITCC.