IIntrinsically safe DCS/PLC cards

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Thread Starter

pandu

hi

Recently I came to know many DCS/PLC manufactures are coming with Intrinsically safe built-in AI/AO/DI/DO cards.

what is difference between this Built-in and
std.i/o card + external barrier.

if like i have an instrument or relay not certified for Intrinsically safe, but installed in hazardous area then can`t I use these Built-in cards.

somebody is telling me i can not use them and i have to use standard card with external barrier. but my question is how it makes difference between Bulit-in, std.i/o+external barrier.

hope somebody can help me

thanks
pandu
 
>have an instrument or relay
>not certified for Intrinsically safe,

If the device is not certified by recognized 3rd party as intrinsically safe with associated entity parameters and has an IS approval label on the device, then you can not install it in a hazardous area. even if you use IS barriers, because it has not been certified intrinsically safe.

You can do an installation with explosion proofing enclosures and purging, but those techniques are NOT intrinsically safe.
 
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