HART without 4-20 mA?

Field Network Q&A

Can we have a HART network without using 4-20 mA?

Expert’s answer: HART without 4-20 mA?

No, you can’t have a HART without 4-20 mA. The HART network depends on analog communication. You can read more about the protocol here.

When you have a multidrop network, the current stays in 4 mA. Thus, you might say that you don’t have the 4-20 mA modulation, because the current stays at 4 mA and the process information comes from the HART communication.

HART without 4-20 mA
HART communication (copyright HART Foundation)

With that in mind, you have other HART protocols that technically don’t have 4-20 mA. For example, wirelessHART and HART-IP. Both protocols are HART, but they provide digital communication based on wireless and Ethernet.

For more information, please check the list below:

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Related tags: 4-20mA FSK HART HART communication HART communicator hart foundation Multidrop
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