YASKAWA GA500 series - Page 184

2.3 b: Application
184 YASKAWA TOEPYAIGA5002A GA500 Programming
■ PID Control Block Diagram
Figure 2.28 PID Block Diagram
■ PID Feedback Loss Detection
The PID feedback loss detection function detects broken sensors and defective wiring between the drive and sensors.
Use the PID feedback loss detection function when you use PID control. If the feedback signal is too low, the motor
can suddenly accelerate to the maximum output frequency. This function prevents such risks to the load.
The drive uses two methods to detect feedback loss:
• PID Feedback Loss [FbL]
Set these parameters for the PID feedback loss detection function.
The drive detects feedback loss when the feedback value is less than the value in b5-13 for longer than the time in
b5-14.
– b5-12 [Feedback Loss Detection Select]
– b5-13 [PID Feedback Loss Detection Lvl]
– b5-14 [PID Feedback Loss Detection Time]
• Excessive PID Feedback [FbH]
Set these parameters to set how the drive detects a feedback level that is too high.
The drive detects too much PID feedback when the feedback value is more than the value in b5-36 for longer than
the time in b5-37.
– b5-12 [Feedback Loss Detection Select]
– b5-36 [PID High Feedback Detection Lvl]
– b5-37 [PID High Feedback Detection Time]
Figure 2.29 shows the operation principle when the feedback value is too low, and the drive detects feedback loss.
The operation is the same when the drive detects too much feedback.