from the Forum department...
ATEX certification (ATEX II 2 G Eex ia IIC T6) and power supply requirements of instruments
Engineering and workplace issues. topic
Posted by Anonymous on 13 November, 2009 - 5:13 am
I want to know from the experts of this forum whether power supply for the instruments like Magnetic flow meter installed in Zone 2 areas can be 230 VAC, 50 Hz along with 4-20 mA IS (passive) as output when we specify the requirement of ATEX certification (ATEX II 2 G Eex ia IIC T6.

I understand that when we have specified the instrument as Eex-ia (intrinsically safe)which is going to be installed in Zone-1 or 2 area then 230 VAC can not go to the field. And if we require 4-20 IS (passive) mA output from the instrument then we may have to either look for the instruments that are 24 VDC loop powered or if that is not possible and only 230/ 110 VAC is required to power the instrument then we may have to change the protection technique to Eex-id (flame proof).

Please correct me if I am wrong and suggest the way around.

I am not sure whether Magnetic flow meters or Radar level transmitters come 24 VDC loop powered.

Or is there any way by which we can separate the meter and transmitter part (may be in safe area).

Thanks in advance.



Posted by Bruce Durdle on 13 November, 2009 - 2:33 pm
A field transmitter rated as Ex i with no other method of protection will need to have all circuits fed to it protected by barriers. So you will not be able to use a 230 V power supply with it. However, you can get apparatus which has an enclosure for power supply terminals rated as Ex e or Ex d, together with separate signal circuitry rated as Ex i. The apparatus itself will then generally incorporate the energy limiting barriers or isolators for the IS circuitry (since it is a source for these signals rather than using an external power supply) and this equipment will then be certified as Ex e[i] or Ex d[i].


Posted by nik on 15 November, 2009 - 11:57 pm

Good reply,

But let me know whether this is an example of an ideal case or is commercially available. As the requirement is for an integral transmitter assembly.

Did you mean to say that for taking care of 230 VAC supply flameproof enclosure will be there and the output of the transmittter which is 4-20 ma IS will also be in the same housing and will be connected to DCS through barrier.

Any vendor with model nos???


Posted by Bruce Durdle on 17 November, 2009 - 12:08 am
For example, ag-6000-i-6000-i-ex-d-11592.htm


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