PID Feedback below min. Value

What does F00221 mean?

The feedback signal for the PID controller has dropped below its configured minimum threshold (p2268). This indicates an issue with the feedback sensor, its wiring, or an incorrect parameter setting, causing the PID loop to lose its reference and potentially leading to unstable control or undershoot.

• Feedback sensor (e.g., pressure transducer, flow meter) failure, providing 0V, 0mA, or a very low output signal.
• Wiring fault (e.g., open circuit, loose connection, short to 0V) in the analog feedback signal path to the drive's input terminals (e.g., AI0 on terminals 1 & 2).
• Incorrect configuration of the minimum feedback value parameter (P2268) or the analog input scaling (P2265, P2266).
• The actual process variable is genuinely below the configured minimum threshold (e.g., tank empty, no flow) and not a sensor or wiring issue.
• Analog input module or channel fault on the drive (e.g., AI0 input) preventing accurate signal reading.

Click steps to track your progress.

1. 1

   1. Use a multimeter to measure the analog feedback signal voltage or current (e.g., 0-10VDC or 4-20mA) directly at the sensor output terminals.

2. 2

   2. Measure the same analog signal at the drive's analog input terminals (e.g., terminals 1 & 2 for AI0) to check for wiring integrity between the sensor and drive.

3. 3

   3. Verify drive parameter P2268 (PID feedback minimum value) is correctly set to reflect the expected minimum operational feedback value.

4. 4

   4. Check analog input scaling parameters P2265 (Feedback actual value filter time) and P2266 (Feedback actual value offset) for proper configuration.

5. 5

   5. Inspect the sensor power supply (e.g., 24VDC) at the sensor terminals for correct voltage and stable current delivery.

6. 6

   6. Simulate a valid feedback signal (e.g., 5VDC or 12mA) at the drive's analog input terminals to test the drive's response independently of the sensor.