YASKAWA G7 Series Technical Manual page 324

PID Feedback Loss Detection
When performing PID control, be sure to use the PID feedback loss detection function. If PID feedback is lost,
the Drive output frequency may accelerate to the maximum output frequency.
When setting b5-12 to 1 and the status of the PID feedback value detection level in b5-13 is insufficient and
continues for the time set in b5-14, an FbL (PID feedback reference lost) alarm will be displayed on the Digi-
tal Operator and Drive operation will continue.
When b5-12 is set to 2, an FbL (PID feedback reference lost) error alarm will be displayed on the Digital
Operator, the error contact will operate, and Drive operation will be stopped.
The time chart for PID feedback loss detection (set b5-12 to 2) is shown below.
PID Sleep
The PID sleep function stops the Drive when the PID sleep function delay time continues while the PID con-
trol target value is at an insufficient level to operate the PID sleep function. When the PID sleep delay time
continues and the PID control target value is above the PID sleep function operation level, Drive operation
will automatically resume.
When PID control is disabled, the PID sleep function is also disabled. When using the PID sleep function,
select decelerate to stop or coast to stop as the stopping method.
The PID sleep time chart is shown below.
Internal run command
External run command
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PID feedback value
Loss detection
level
(b5-13)
Loss detection time
(b5-14)
Fig 6.61 PID Feedback Loss Detection Time Chart
PID target value
Sleep operation
level b5-15
Sleep operation
delay time
b5-16
Operation
Operating
Fig 6.62 PID Sleep Time Chart
No FbL
detection
FbL detection
Loss detection time
(b5-14)
Sleep operation
delay time
b5-16
Stopped
Run command has been input
Operation status output
Time