AI isolated barrier is common connect with field instruments: two/ three-wire transmitter/current source.
The current source is an active 4~20mA signal that does not require a isolated barrier or an independent power supply for distribution.
For example: The power supply of Ex ia four-wire transmitter is provided by the IS power supply alone, and the 4-20 mA signal is the current source signal.
The transmitter is a passive 4-20 mA signal that requires a isolated barrier or an independent power supply for distribution
For example: The power supply of Ex ia 2-wire transmitter/Ex i 3-wire IS transmitter is provided by the isolated barrier, and the transmitter outputs 4-20mA current signal.
24 V independent power supply