HART Isolator

M

Thread Starter

Marcos Giorgianni

Dear List Members,

I am working on project using some HART transmitters.

Now, the end customer wants to isolate the HART signal before send it to the DCS.

Could you, please, help me to find a device to isolate the HART signal?

Is there any company doing this?

Thank you all


M.Giorgianni
BRASIL
 
A

Arnold Dillon

Fisher Rosemount offers a Hart Isolator. At least my local rep. firm handles them. Placed in-line with the basic 4-20 milliamp signal, this
unit picks off the digital information, and sends out a separate scaled 4-20 milliamp signal that is proportional to the second Hart variable.
 
W
Dear Marcos,

Your request seems to be for a filter circuit to separate the HART Signal from the DC 4-20mA signal. Many DCS's have a low pass filter already incorporated into their input circuitry. This filter is designed to reject process "noise"
and at the same time it rejects the HART Signals. If you will provide me with the DCS vendors name perhaps I can contact them to discuss this issue. There are many DCS vendors that are members of the Foundation.

In regard to you need for a filter. I know of no company making such a product. Normally such filter can be constructed using a simple Resistor Capacitor combination. I guess there is not generally much revenue potential for such a
product. I will check around the Foundation to see if anyone makes such a product.

I don't believe the following are what you are looking for

> Date: Mon, 28 Aug 2000 15:07:02 -0700
> From: Arnold Dillon <[email protected]OMASSON.COM>
> Subject: Re: COMM: HART Isolator
>
> Fisher Rosemount offers a Hart Isolator. At least my local rep. firm
> handles them. Placed in-line with the basic 4-20 milliamp signal, this
> unit picks off the digital information, and sends out a separate scaled
> 4-20 milliamp signal that is proportional to the second Hart variable.


I believe this is refering to the Rosemount Tri-Loop. This product receives burstmode messages and generates a 4-20mA signal for up to three secondary measurements from a multi-variable HART Field Device.


> Date: Mon, 28 Aug 2000 18:08:01 -0400
> From: Larry Kolbert <[email protected]>
> Subject: COMM: HART Isolator
>
> Elcon in the UK makes one.

Elcon makes intrinsic safety barriers and HART compatible I/O systems (i,e. multiplexers). I talked with Elcon this morning and I am not sure this is what you are looking for. In other words they do not make a simple filter circuit to
separate out the DC 4-20mA from the HART signal.

> From: "Adrian Chesney" <[email protected]>
> To: "The Automation mailing list, managed by Control.com Inc."
> <[email protected]-control.com>
> Subject: Re: COMM: HART Isolator
>
> The HART Book includes many Isolator products from many
> different suppliers, try www.thehartbook.com

The HART Foundation also has web pages containing a many HART product catalog listings. However, I believe "Isolator" referes to intrinsic safety barrier products. If you are looking for an IS barrier product you can contact Elcon, MTL, Ronan, Stahl, Pepperl+Fuchs, etc. There are contacts listed in our web site.

The HART Communication Foundation supports industry world-wide in the application, training etc. on the HART Protocol. If you need additional
assistance feel free to contact us.

Best regards,

Wally Pratt
Chief Engineer
HART Communication Foundation.
http://www.hartcomm.org
 
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