User's Manual
“B” Group: Fine-Tuning Functions
Configuring Drive 
Parameters
3–40
Controlled Deceleration at Power Loss – When enabled, this feature permits the inverter to 
control final motor deceleration upon loss of inverter input power. First, you must make a 
wiring change to the inverter. See “
Optional Controlled Decel and Alarm at Power Loss” on 
page 4–4 for complete instructions including wiring and signal timing diagrams for using the 
controlled deceleration at power loss feature.
After making the wiring change, use function B050 to enable the feature. Use B051 to deter-
mine the point at which a decaying DC bus voltage will trigger the controlled deceleration. Use 
parameter B054 to specify an initial step-wise deceleration at power loss, and B053 to specify 
the duration of the linear deceleration.
During the controlled deceleration the inverter itself acts as a load to decelerate the motor. With 
either a high-inertia load or a short deceleration time (or both), it is possible that the inverter 
impedance will not be low enough to continue linear deceleration and avoid an over-voltage 
condition on the DC bus. Use parameter B052 to specify a threshold for the over-voltage. In 
this case, the inverter pauses deceleration (runs at constant speed). When the DC bus decays 
again below the threshold, linear deceleration resumes. The pause/resume process will repeat as 
necessary until the DC bus energy is depleted (under-voltage condition occurs).
B046 Reverse Run protection 
enable
Prohibits reverse motor 
rotation. Two option codes:
00 Disable
01 Enable
✘ ✔ 00 00 00 —
>b046 LIMIT
PREV  OFF
“B” Function
Run 
Mode
Edit
Lo Hi
Defaults
Units
SRW Display
Func.
Code
Name Description
–FE
(CE)
–FU
(UL)
–FR
(Jpn)
“B” Function
Run 
Mode
Edit
Lo Hi
Defaults
Units
SRW Display
Func.
Code
Name Description
–FE
(CE)
–FU
(UL)
–FR
(Jpn)
B050 Controlled deceleration 
and stop on power loss
Allows inverter control 
using regenerative energy to 
decelerate after loss of input 
power (requires jumper 
change)
Two option codes:
00 Disable
01 Enable
✘ ✘ 00 00 00 —
>b050 IPS-DECEL
Mode  OFF
B051 DC bus voltage trigger 
level during power loss
Sets trigger for controlled 
deceleration and stop on 
power loss function.
Range is 0.0 to 1000.V
✘ ✘ 0.0 0.0 0.0 VDC
>b051 IPS-DECEL
V1 0000.0Vdc
B052 Over-voltage threshold 
during power loss
Sets over-voltage threshold 
for controlled deceleration 
function.
Range is 0.0 to 1000.V
✘ ✘ 0.0 0.0 0.0 VDC
>b052 IPS-DECEL
V2 0000.0Vdc
B053 Deceleration time 
setting during power 
loss
Range is 0.01 to 99.99 sec. /
100.0 to 999.9 sec. /
1000 to 3600 sec.
✘ ✘ 1.00 1.00 1.00 sec.
>b053 IPS-DECEL
TIME 0001.00s
B054 Initial output frequency 
decrease during power 
loss
Sets the initial decrease in 
output frequency upon 
power loss.
Range is 0.00 to 10.00 Hz
✘ ✘ 0.00 0.00 0.00 Hz
>b054 IPS-DECEL
DEC-F 00.00Hz










