FM Pressure Transmitter and UL Current Recorder

[Grasshopper7]

Hi,

I'm building a recorder to record a 4-20mA signal in Class 1, Div 1 applications. I'm going to get the unit certified with UL to have intrinsically safe outputs. I'm now looking around on the market for what devices I can connect to my recorder. A typical unit is Rosemount Pressure Transmitters. These have FM approval for Class 1, Div 1, Intrinsically safe.

My question is, can I connect the two of these together (assuming that the electrical specifications of the outputs of the Rosemount unit and the inputs of my recorder are within specification of the certifications from UL and FM)?

Will this be accepted within industry? Is this normal to do?

Thanks

Grasshopper

 

[DRWeig]

Yes, it's normal when designing intrinsically safe systems by the entity method.

Be sure to add in your cable parameters.

Look here for more info:

http://www.mtl-inst.com/images/uploads/datasheets/App_Notes/AN9003.pdf

Best to you,

Goober Dave

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[Grasshopper7]

Hi Goober Dave,

Thanks for getting back to me and the reference you provided.

The system that I'm building isn't intrinsically safe - it just has intrinsically safe input - the rest is certified explosion proof. I'm trying to figure out whether once this thing gets to a customer on-site that they are going to be happy to connect up a box that has UL certification with a sensor with FM certification. I shouldn't see any problems in the field?

Cheers.

 

[DRWeig]

Yes, as long as your sensor (FM) is also explosion proof -- OR the input that you describe is a listed intrinsic safety barrier within your explosion proof enclosure and the parameters all match up with the field (intrinsically safe) device.

As you go through UL with your system, they'll help you with the required labeling and stuff for the input to be connected in the field.

If I'm confused, it might be best to give us a sketch -- block diagram of sorts. I'm making assumptions that I probably am getting wrong...

Best to you,

Goober Dave

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