Bentley and SIS
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There are 4 probes for unit vibration, and I’m considering using a 2-out-of-4 voting system. Which is better – to implement this voting on the Bentley 3500 or on the TRICON system? Thank you for the guidance.
I’ve really never seen a four-out-of-two system for machine vibration; usually, the vibration from the drive side and the non-drive side is each evaluated using a two-out-of-two approach. This type of cascading logic can be implemented either on 3500 or on SIS; both are mature applications. There is a slight difference: by using 3500, it eliminates the need for additional relay points; it’s sufficient to use the logic relay to provide one interlock point for the SIS. The downside is that it becomes difficult to determine which specific point is responsible for the interlock after it is established. In SIS, apart from adding relay points and cables, there’s not much else to do.
If the logical relationship design is in SIS (choose 2 out of 4), it is best to carry it out on the SIS system.
It is recommended to do it on SIS, as this will reduce future troubles; I’m not sure whether the 3500 has a SIL rating certification. (The probe also requires corresponding SIL certification)