9-5 
9.4   Sleep / Wakeup Function 
 
The PID Sleep function can be used to prevent a system from running at low speeds and is frequently used in 
pumping application. The PID Sleep function is turned on by parameter 10-29 set to 1. The inverter output turns 
off when the PID output falls below the PID sleep level (10-17) for the time specified in the PID sleep delay time 
parameter (10-18).   
 
The inverter wakes up from a sleep condition when the PID output (Reference frequency) rises above the PID 
wake-up frequency (10-19) for the time specified in the PID wake-up delay time (10-20). 
 
PID 
Target
Value
Feedback
Value
+
-
PID=OFF
PID=ON
f          
  
Soft Start
Output
Frequency
( Fout )
PID 
Sleep/Wake- up 
function
(Fref)
Freq Reference
t 
 
10-18
Hz
T
10-19
10-17
10-20
Wake up
frequency
Sleep
frequency
PID output frequency
Actual output frequency
 
PID Sleep Function