Issues with replacing FF bus instruments
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I’ve been learning about *FF bus instruments recently, and I have a question: in an explosion-proof area, if one of the instruments connected to the bus fails and needs to be replaced, how is that done? If it is powered by a bus, then wouldn’t cutting off the bus power cause all the instruments on that network segment to stop working? Because I see that the explosion-proof junction box in the picture doesn’t have a separate switch.
The segment protector is a isolation barrier; as long as the segment protector remains in place, the field FF instruments should be in intrinsically safe mode.
No, for on-site instruments to be connected to the main line, a terminal is required. A terminal is a standard device that includes terminal resistors, short-circuit protection, and so on; therefore, failures of the on-site instruments will not affect the main line
I mean, the junction box is explosion-proof – how can it be opened while there is electricity present in an explosion-proof area? Unless everything connected above are intrinsically safe instruments, right?