Whether there’s a difference between the HART and FOUNDATION Fieldbus networks depends on how your devices are set up. If they only read 4-20 mA outputs, then yes, you’ll receive fewer data on a HART network. In fact, all relevant diagnostics and features will die in the field!  You have to configure your devices to send their digital data as well, or the control system will only receive the process values through the 4-20 mA.

HART network

Quantum system with HART card diagram
Quantum system with HART card

Fortunately, a HART system offers the same intelligent device management (IDM) that you’d find in a FOUNDATION Fieldbus (FF) device. As a matter of fact, a HART network can provide easy setups for your transmitters through its configuration tool. Of course, your control system will need to use 4-20 mA to control loops, which is the main disadvantage when we compare HART and Fieldbus.

FOUNDATION Fieldbus network

foundation fieldbus network diagram
Foundation Fieldbus – Copyright Relcom Inc.

FF offers digital communication from the primary device to the final control element. You also have the IDM in all devices, providing the same level of information as HART. FF uses digital communication and HART uses analog, so it makes more sense to compare FF and 4-20 mA.

For more information about both networks, check the links below:

Other resources that might interest you

HART Communicator: When to Use
I have a question about HART communicators. Can you help? When we have a local configuration, when do we use the HART communicator?

HART theory
Could you explain how it’s possible to send a digital communication through an analog signal?

I’d like to know if a converter or a gateway can connect a HART device in an FF network without data loss from the field devices, or if we should stay with a HART over PROFIBUS remote IO. Could you explain?

Both FF and HART can provide field data to the marshalling cabinet. Which is more reliable for the oil and gas industry?

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