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.
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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