YASKAWA F7 Programming Manual page 54

The direction in which speed is controlled is determined by the sign of the speed limit signal and the direction of the run command.
Positive voltage applied: The speed in the forward direction will be limited for forward operation.
Negative voltage applied: The speed in the reverse direction will be limited for reverse operation.
If the direction of the motor rotation and the command direction are not the same, speed will be limited to zero as long as d5-
05 is set to zero. The direction of the run command determines the polarity of the speed limit.
Example:
Fmax - E1-04 = 60 Hz
Speed limit bias - d5-05 = 10%
No load on motor - Drive will always run up to speed limit
Run Direction
FWD
FWD
REV
REV
Speed Limit Bias Setting
The speed limit bias can be set to limit both the forward and reverse speed to the same value. This differs from the operation of
the speed limit bias setting. To use the sped limit bias, set d5-04 to 0 and set the bias in d5-05 as a percentage of the maximum
output frequency.
To set 50% forward and reverse speed limits, set the speed limit setting to 0 (d5-03 = 2, d5-04 = 0, and d5-05 = 50). The range
of torque control will be from -50% to 50% of the maximum output speed.
When using both the speed limit and the speed limit bias, the range of torque control will be positive and negative speed limits
with the speed limit bias added to each.
The range of torque control when the forward speed limit is 50% and the speed limit bias is 10% as shown in the following
figure. This figure does not take the priority circuit into account.
Reverse Operation
R everse O perati on
Torque Reference
100%
-100%
100%
-100%
Positive Torque P osi ti ve Torque
Speed limit bias
Speed l i m i t bi as
d5-05
d5-05
Negative Torque
N egati ve Torque
Fig. 36 Speed Limit Bias Setting
Programming 46
Output Frequency
46Hz
-6Hz
6Hz
-46Hz
Delta N = Tref % / C5-01
D el ta N = Tref % / C 5-01
d5-04 d5-05
d5-04 d5-05
Forward Operation
Forw ard O perati on