there is an existing Krohne optiflux 4300 C (electromagnetic flow meter) with Basic I/O and with no marking for EX area. two days ago I removed the transmitter cover and look at sth strange that it was written [EEx ia] at the back of transmitter electronic modules where there is no ex marking on instrument tag. if sb knows please help me to realize whether the existing flow meter with no ex marking on its tag no and with ex marking on the inner side of the transmitter like [EEx ia] is intrinsically safe or not? or basically what is the exact difference between EEx ia and [EEx ia]?
Pardon this fortune. Database under reconstruction.