Hi
I would like to ask about Ex'i' certified transmitter.

As I know, At intrinsic safety circuit, Barrier limit P, I, V from non-hazardous area, So that is not possible to make spark after barrier

1.So What is function of Ex'i' Transmitter? and what is differences between ex'i' certified and non-ex'i' transmitter?

2.If Ex'i' certification means that "This transmitter is safe only under the specified Vi, Ii, Pi", What happen when we used Pi(Tx) < Po(Barrier)?

Is that means "We used Ex'i' Tx and Barrier but Not Intrinsic safe loop?

Thanks.

 

Ex = explosion proof
i = intrinsically safe

Barrier and loop wiring are IS standard.

More info: http://www.engineeringtoolbox.com/hazardous-areas-classification-d_395.html