Can a PLC replace a SIS system?
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If that’s not possible, are there any standard documents that specify it?
It is possible to use a safety PLC together with relays; the standards do not specify the form of safety instruments
How can a PLC replace a SIS? In that case, large-scale factory DCS systems could dominate the market! That’s impossible; the concepts are different!
As I understand it, sis can be implemented using either PLC or DCS systems; the only difference lies in the permissions and the state after activation.
The instruments and valves in the SIS system have an SL rating.
Experts say that SIS DCS needs to be independent, and even requires a separate UPS; how is it possible to control it using PLCs and DCS? Perhaps the same effect can be achieved, but the specifications do not allow it.
There are no standards. SIS control system = safety functions + PLC. PLCs with safety functions (or safety certificates) are considered SIS control systems. There’s no need to get stuck on definitions.