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Join Date: Jun 2007
Posts: 24

HART Pressure Transmitters

12/12/2008 1:50 AM

We are going to purchase a HART 4-20 mA pressure transmitter. Can I use this transmitter in the conventional 4-20mA current loop without using the HART functionality.

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Power-User
South Africa - Member -

Join Date: Nov 2008
Location: Johannesburg
Posts: 295
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#1

Re: HART Instrument

12/12/2008 2:03 AM

Hi there,

Yes you can. If you want to use the HART functionality - your input card would need this facility. The HART signal is only superimposed over the 4-20mA which is what you are interested in.

Just as a matter of interest, most trasmitters today come with HART already, but not many people use the actual functionality.

So in a nutshell - you can definately use the instrument as you would in a conventional 4-20mA loop.

Regards

Craig

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Anonymous Poster
#2

Re: HART Pressure Transmitters

12/15/2008 3:50 AM

Yes you can, without anydoubt.

The Hart functionnality will remain there and you can access to them via a pocket.

The Hart signal is a digital protocol which is carried (as an FSK signal) over the 4-20mA signal.

Enjoy

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Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

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Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
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#3

Re: HART Pressure Transmitters

12/19/2008 4:08 AM

Yes, as all the others above have indicated.

Check-out the Wikipedia page on the Hart Protocol for confirmation reading. It's a calibration/transmission system that is superimposed upon the 4-20mA analog loop without interference between them - that's the beauty of it. The transmitter will behave just like a non-Hart transmitter if the Hart stuff isn't in use. Come to think of it, it will do the same if the Hart stuff is in use as well.

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