Instrument communication in explosion-proof areas
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A beginner in explosion-proof areas is asking: There is a flow meter in an outdoor gas station that is intrinsically safe, and it operates in Zone 2. It is said that Rs485 communication should be used to connect it to the DCS cabinet room. Compared to an analog 4-20mA signal, is it necessary to use a safety barrier for the 485 communication? What actions need to be taken regarding the cards on the Dcs side, or what other cards should be used?
The intrinsically safe circuit should be equipped with safety switches; both ends of the armored cable must be grounded, and the shielding layer at the cabinet end must also be grounded
Does the safety barrier for intrinsically safe instruments apply to analog signals, or does it cover various communication methods as well?
Although I have not used a 485 communication safety barrier, there are indeed digital communication input safety barriers.
Is 485 communication an analog signal? ? ?