What is the primary difference between PV and SV in HART data?

• A. PV is the current loop value representing process variable; SV is the desired setpoint value as commanded by a controller.
• B. PV is the process velocity; SV is sample value.
• C. PV and SV are both the same concept; there is no difference.
• D. PV is the value stored in nonvolatile memory; SV is the value read-only.

Answer: (A)

The main idea here is that PV and SV serve two different roles in a control loop. PV is the actual, real-time measurement of the process variable—the current state the sensor reports. SV is the setpoint, the target value that the controller wants the process to reach. For example, if a temperature loop shows a PV of 75°C but the SV is 80°C, the controller will drive the actuator to raise the temperature toward 80°C. This distinguishes PV as the live value you observe from the process, and SV as the commanded value you aim to achieve. The other statements mix up these roles: PV isn’t a velocity or a sample value, they aren’t the same thing, and SV isn’t simply a stored memory value.