What is the role of a HART slave (field device) in the network?

• A. To respond to master requests and provide measurement values, status, and diagnostic data.
• B. To initiate communication with the master and assign addresses.
• C. To exclusively provide power but no data.
• D. To control other devices on a separate bus.

Answer: (A)

In a HART network, a field device acts as a slave that responds when the master asks for information. The master controls the conversation, polling devices and requesting data. The slave’s job is to reply with the process variable (measurement values), its current status, and diagnostic data. The digital data rides on top of the 4-20 mA current loop, and the device is powered by that loop rather than supplying power to others. This makes the role clear: the slave provides data in response to master requests, not initiate communication, assign addresses, power other devices, or control a separate bus.