SIS system isolation safety barrier and signal isolator
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The field instruments are explosion-proof; they are not intrinsically safe instruments. When connected to the SIS system, should an isolation safety barrier or a signal isolator be used?
Explosion-proof, not intrinsically safe – does that mean flameproof? Isolation safety barriers and signal isolators – are these terms not properly named? Aren’t they the same thing?
Explosion-proof instruments do not require a safety barrier; take a look at this: https://bbs.hcbbs.com/thread-1268545-1-1.html
Isolated, non-intrinsic safety equipment can use isolators, while intrinsic safety equipment must be equipped with safety barriers due to the requirements related to limited energy output. However, whatever is used in SIS needs to be certified
I’ve encountered many clients who request the addition of safety shields; any device used in explosion-proof environments has such shields installed. Many times it seems like an unnecessary task or even something redundant, but as a precaution, it’s better to add an extra layer of protection.
1. Non-intrinsic safety instruments do not require a safety barrier. 2. The signal isolator only needs to be used with signals that may be subject to strong electrical interference. The others don’t need to be considered.
The 6th floor is correct; a safety barrier cannot restrict energy either for non-intrinsic safety instruments.