I have a question regarding SIS’s ability to receive DCS signals
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Instruments connected to the SIS must all meet the SIL rating requirements. As for signals connected to the DCS, does the DCS not have a SIL rating? Is that how the regulations work in this regard?
SIL: Safety Instrument Level; SIS: Safety Instrument System. A safety instrument system can be established only when it meets certain safety levels. DCS is primarily used for control functions – what is its relationship to the SIL level?
The SIL level is composed of SIF. Calculate the SIF of the circuit.
DCS systems generally have a reliability level of SIL1 by default, and they can be used as SIS systems. When a SIL2 level is required, some DCS systems are capable of meeting that standard; therefore, it is necessary to consider the requirements of your SIS. If only a SIL1 level is needed, then a DCS will suffice, but if a SIL2 level or higher is required, special consideration must be given
There are no regulations. But it must meet reliability requirements. One of the differences between DCS and SIS is that SIS does not allow any loss of functionality (it must be foolproof), while DCS requires that the loss of some functions does not affect the other functions (risk dispersion). The main reason why DCS communication signals are generally not used as SIS signals is: 1. There is a possibility that signals cannot be transmitted via DCS ； 2. The DCS reaction is slow. The DCS polling cycle ranges from hundreds to thousands of milliseconds, while the response time of SIS is usually in the millisecond range. If the two reasons mentioned above are not a concern, SIS can use DCS signals. However, the accurate description at this point should not be that SIS uses DCS signals, but rather that DCS utilizes SIS functions.