What is HART protocol, and how does it coexist with a 4-20 mA loop for field instrumentation?

• A. HART is a standard that adds a digital signal alongside the 4-20 mA loop for device configuration and diagnostics.
• B. HART uses only digital signals and eliminates the analog loop.
• C. HART is a wireless protocol used for remote sensors.
• D. HART requires separate power supply; cannot operate on a 4-20 mA loop.

Answer: (B)