How to qualitatively describe SIL1, SIL2, SIL3, and SIL4? What can be placed in DCS?
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How to qualitatively describe SIL1, SIL2, SIL3, and SIL4? What can be placed in DCS?
Dcs can’t be used as SIS, so it has nothing to do with SIL
This should be used to evaluate the interlock level; both DCS and SIS can be used for this purpose, with higher levels generally being handled by SIS
DCS and SIS are two completely different concepts; DCS is a control system (including hardware, software, and HMI), while SIS is a system of instruments designed to implement safety functions. The SIS is at the top level; the DCS is primarily responsible for process control, while the safety system SIS is also at the top level.
SIL certification is divided into 4 levels in total: SIL1, SIL2, SIL3, and SIL4, covering both the product and system levels. Among them, the requirements for SIL4 are the highest. The SIL level that safety-related systems should achieve is determined through risk analysis, which is derived by comprehensively evaluating four factors: the severity of the risk consequences, the duration and frequency of exposure to the risk, the probability that the risk cannot be avoided, and the probability of occurrence of undesirable events. The higher the level, the lower the required probability of hazardous failure. See the figure below
SIS and DCS are two completely independent systems. DCS can’t hold anything. Regardless of how low the SIL level is, safety interlocks should not be configured in the DCS