Dear Sir,

Kindly, please clarify the following issue:

- I'll replace an FOXBORO positioner using Foxcom protocol with ABB positioner using 4-20 MA HART protocol considering the available DCS is FOXBORO.

The question is, what the suitable way to achieve this connection between the FOXBORO DCS and ABB positioner?

Waiting your kind reply.

Thanks and best regards,
Nidal Hasan

 

Hi,

In my opinion you should do two steps:

1-Change the DCS program to redirect the output to the valve (PID output in %)from comms output to a phisycal 4-20 mA analog output.

2-Communicate this analog output and the positioner with a new (i.e. 3x1 mm shielded) cable.

If you have more HART devices you should consider to integrate this one onto the HART bus, but if this is not the case I think that the best solution is the above one. You can use the HART conecivity of the device for setting up (configuration)the positioner with a HART communicator.

Regards,

Torre

 

Dear Mr. Torre,

Thanks for your kind reply.

I understand from the second solution that it's able to connect an ABB Positioner HART, with FOXBORO DCS use Foxcom protocol.

Best Regards,
Nidal

 

Nidal,

Sorry, maybe my explanation has not been clear enough. I do not think that Foxcom and HART are compatible. You must do both steps, in this way the new positioner would be out of the Foxcom bus. Foxcom is a proprietary bus of FOXBORO, while HART is an open BUS. (Many brands develop HART compatible devices.)

Regards,

Torre