Active and passive
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How exactly is the distinction made between active and passive components? I’d appreciate it if an expert could explain this
The mA circuit can be active or passive; in simple terms, it refers to whether the milliampere range is capable of measuring milliampere signals. The signal circuits of four-wire instruments are generally active; it is necessary to terminate them in a passive manner at the system side, or to use a signal regulator to convert them to a passive configuration for termination at the system side. The signal circuits of two-wire instruments do not have their own power supply, so they are all connected in an active manner at the system side. Analogous to three-wire instruments. I’m not sure if it’s understandable: lol
In simple terms, a DCS loop does not have sufficient power supply to operate the instruments; those that require a separate power supply from the distribution cabinet are active loops, while others are passive loops.
Hahahahaha, “active/passive” – the advantage of using simplified language lies in avoiding complicated explanations: lol. Fortunately, it’s used within this limited context; if it were applied more generally, its meaning would become much broader: lol