YASKAWA Varispeed E7 Instruction Manual And Parameter Description page 228

PI Snooze Function
By setting b5-21 to 2 the PI snooze function can be enabled. This software observes the output frequency
(Softstarter output) and the PI feedback value to turn the inverter ON and OFF automatically as the system
requires.
Snooze Activation
•
The inverter stops operation when the output frequency (Softstarter output) falls below the snooze level
b5-22 for a longer time than the snooze delay time b5-23 and the feedback value is above the snooze feed-
back value in b5-27. Before stopping the inverter finally, the PI setpoint is boosted up to temporarily
over-satisfy the load and thereby to avoid a short cycle ON and OFF switching of the inverter. The boost
level is set in constant b5-25 and it is set as percentage of the PI setpoint value, but the maximum time for
boost operation is set in b5-26.
Wake up
•
The inverter resumes the normal PI operation when the PI feedback exceeds the wake up level b5-24. The
normal acceleration ramp is used.
PI Setpoint
Setpoint Boost (b5-25)
PI Feedback
Snooze Feedback Level (b5-27)
Wake-Up Level (b5-24)
SFS Output Freq.
t < b5-23
Snooze Level
(b5-22)
Normal PI operation
Using the constant b5-21 either sleep operation or snooze operation can be enabled. It is impossible to
enable both functions at the same time.
NOTE
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Snooze Delay
(b5-23)
Boost
Fig 6.52 PI Snooze Time Chart
Individual Functions
time
PI Setpoint + b5-25
time
normal
decel.
ramp
normal
accel.
ramp
time
Normal PI
Snooze
operation
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