SIL requirements for transmitters
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A problem has arisen in the engineering process: since the process package requires that the circuit be of SIL3 level, the transmitter used for monitoring this circuit must also be SIL3 rated. The supplier told me that their SILs are configured with redundancy, meaning two pairs of wires are fed into the system. Who has used SIL3 transmitters? Are all SIL3 systems implemented using transmitters for redundancy? Then why am I still SIL3? I might as well just modify the circuit and make the measurement unit a three-out-of-one or two-out-of-one system? The price can be lower
Can a single transmitter achieve SIL3? I have used SIL2; by using a 2-out-of-1 design with diagnostic functions, it is possible to achieve SIL3, or one can use a 3-out-of-2 design. If there is indeed a single unit that reaches SIL3, theoretically redundancy is not necessary. Ask the supplier to show me the safety certification for his product; I don’t think that’s possible. Last edited by hwindforce on 2009-2-26 at 16:39.]
The so-called SIL3 refers to the safety level that needs to be achieved during design; generally, it requires three identical components to operate simultaneously, with a 2-out-of-3 voting system applied after three signals undergo ESD protection.
At present, there seem to be no SIL3 transmitters that meet the requirements of IEC61508 and are certified by TUV or e*da. Even if manufacturers claim that their products meet these requirements, it is only partial compliance – for example, the PFD value may meet the specifications – but such claims from manufacturers are merely for reference only and have no legal validity. For SIL3 scenarios, it is recommended to use several instruments with SIL2 certification to establish redundancy.
:handshake :handshake Person on floor 4 agrees with me: lol