🔍 Key Concepts
• Understand the meaning of common PID controller terms: PV, SP, KP, and XO/XOUT
• Relate the block diagram in part A (process, measurement, actual value) to the function block inputs in part B
• Identify which label usually represents the measured process variable in a PID loop
💭 Think About
• In the upper diagram, find where the measurement signal (actual value) comes back to the PLC, then match that role to one of the inputs in the PID block in diagram B
• Ask yourself which of the labels (KP, PV, SP, XO) represents a tuning constant, which represents a target value, which represents a controller output, and which represents the live feedback from the process
• Eliminate the options that clearly are NOT an input for a raw measured signal but are instead a setting or an output
✅ Before You Answer
• Be clear on the difference between setpoint (desired value) and measured value (feedback)
• Identify which parameter is the proportional gain (a tuning constant, not a signal from the field)
• Confirm which tag in the PID block is used for the controller output to the actuator, so you don’t confuse it with the measured-value input