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Definition of HART Protocol
Definition of HART protocol?

I hear the term "HART" protocol, but only have a rough idea what it actually is. Is it in any way related to GPIB protocol?

would someone point to a reference that would give me some basic defintions and a protocol reference.

By James Ingraham on 25 June, 2002 - 5:42 pm

Conviently, "": is "The Official Source on HART Technology."

Yes, GPIB and HART are related, in the same way that any two network protocols are related. Certainly, GPIB and HART are both used primarily for analog data acquisition. The similarites end there, however.

-James Ingraham
Sage Automation, Inc.

By Daniel Chartier on 26 June, 2002 - 6:05 am

HART is a 2-wire, current-loop communication link for instrumentation devices (pressure, flow, level, temperature.... transmitters). It can be used in Ex zones (undes certain conditions). Fisher-Rosemont, Invensys, Foxboro, and other manufacturers of field transmitters have joined to create the HartComm organisation; you can look at their weppage at:

"": .

Hope this helps,
Daniel Chartier

By Steve YATES on 26 June, 2002 - 11:25 am

There is an excellent book written by Romilly Bowden of Fisher Rosemount that describes HART in detail.

I have no idea what GBIB is but HART exists only over 4/20 mA loops, either superimposed over the 4/20mA in a point to point application or in a purely digital form for multi-drop applications (although applications of this are rare)


It's a digital communication system that is superimposed on 4-20mA signals for field devices... nothing to do with GPIB...... developed by Rosemount many years ago and made available to anyone. The HART Communication Foundation now has the rights.

The HART Communication Foundation: "":
The best HART website: "":

Vince Dooley

hey! in what way is it just not related or hasn't anything to do with GPIB? could u give more clarification? may i know ur conceptual frame of mind about HART?

By Wally Pratt on 28 June, 2002 - 3:04 pm

Dear Chris,

HART is not related to GPIB. HART in an enhancement to 4-20mA communication that allows two way digital communication with smart (i.e.,
microprocessor-based) field devices. If you will, HART field device simultaneosly support two communications channels: the 4-20mA communications and modulated two-way digital communications.

I will be glad to answer any questions about HART you have. In addition, there is abundant information about HART on our web site.

best regards,

Wally Pratt (
Chief Engineer
HART Communication Foundation

By Ken Zlotkowski on 30 July, 2002 - 1:17 pm


Do you know of any protocol converter to get HART devices onto ethernet? A Linux based program is what I am looking for.


Ken Zlotkowski

By Ranjan Acharya on 28 June, 2002 - 3:54 pm

A quick search on Google would lead you to many sites. The HART Communications Foundation can be found on URL "":

By Adrian Chesney on 12 July, 2002 - 12:05 pm

You might also want to check out "": it is an indpendant site that has detailed articles of HART technology and applications, it also has hundreds of products and pdf datasheets.

We (SMAR) can do it this way: HART > H1 Fieldbus > HSE Fieldbus on Ethernet.