YASKAWA Varispeed G7 Series Instruction Manual page 366

Torque compensation
from analog input
Torque reference Torque primary delay
from analog input filter
1
Speed limit from analog
input from terminal A1
Speed limit
d5-04
2
d5-03
Speed limit bias
d5-05
Speed feedback
Speed Limiter and Priority Circuit (Speed Limit Function)
If the external torque reference and load are not balanced during torque control, the motor will accelerate in
either the forward or reverse direction. The speed limit function is used to limit the speed to a specified value
and it consists of the speed limiter circuit and priority circuit.
When the motor speed exceeds the speed limit value during torque control, the speed limiter circuit generates
the suppression torque proportional to the speed above the limit value and adds to the torque reference. The
priority circuit switches the internal torque reference to ASR output so that the motor speed does not exceed
the speed limit value.
Application Precautions
There are two ways to set a speed limit: using an input from an analog input terminal and setting a speed limit
in d5-04. The inputs methods for a speed limit are listed in the following table.
Speed Limit Input Method
Constant setting
Voltage input (-10 to 10 V)
Current input (4 to 20 mA)
d5-02
+
Speed controller
(ASR)
−
Speed limiter
Fig 6.70 Torque Control Block Diagram
Location of
Reference
Set in d5-04
Between A1 and AC
Between A2 and AC
Between A2 and AC
+
Priority
Torque limit
circuit
+
+
Refer to torque limit setting
via constants and analog input
Constant
Settings
d5-03 = 2 –
Set H3-01 to 0 if the speed limit between
b1-01 = 1
terminals A1 and AC is always to be posi-
H3-01 = 1
tive.
The sum of the values of terminals A1 and
AC and terminals A2 and AC are the
speed limit. Set H3-09 to 1 to set the speed
b1-01 = 1
limit to the multiplied values of terminals
H3-08 = 1 A1 and AC and terminals A2 and AC. Set
H3-09 = 0 H3-08 to 0 if the speed limit input on A2
is always to be positive.
Turn OFF (V side) DIP switch pin S1-2 on
the terminal board.
The sum of the values of terminals A1 and
AC and terminals A2 and AC are the
b1-01 = 1 speed limit. Set H3-09 to 1 to set the speed
H3-08 = 2 limit to the multiplied values of terminals
H3-09 = 0 A1 and AC and terminals A2 and AC.
Turn ON (I side) DIP switch pin S1-2 on
the terminal board.
Individual Functions
Internal torque
reference
Remarks
6-
133