6
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The direction of the torque output from the motor will be determined by the sign of the analog signal input. It
does not depend on the direction of the Run Command. The direction of torque will be as follows:
•
Positive analog reference: Torque reference for forward motor rotation (counterclockwise as viewed from
the motor output axis).
•
Negative analog reference: Torque reference for reverse motor rotation (clockwise as viewed from the
motor output axis).
Application Precautions
If the analog signal input level is 0 to 10 V or 4 to 20 mA, a forward torque reference will not be applied. To
apply reverse torque, use an input level of -10 V to 10 V or switch the direction using a multi-function input
set to 78 (polarity Reverse Command for external torque reference).
Fig 6.67 Torque Control Block Diagram
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.
Current input (4 to 20 mA)
Between A2 and AC
(Turn ON pin 2 of
SW1.)
H3-08 = 2
H3-09 = 13
To switch the torque reference between
positive and negative torque, set a multi-
function analog input to 78.
The input can be used for torque compen-
sation by setting H3-09 to 14.
Option board (AI-14B)
(
−
10 to 10 V)
Between TC2 and TC4
F2-01 = 0
H3-08 = 1
H3-09 = 13
The input can be used for torque compen-
sation by setting H3-05 to 14.
Torque Reference Input
Method
Reference Location
Selection
Method
Remarks
Torque reference
from analog input
Torque primary delay
filter
d5-02
Torque compensation
from analog input
Speed limit from analog
input from terminal A1
Speed limit
d5-04
1
2
d5-03
Speed limiter
Speed feedback
Speed limit bias
d5-05
+
Torque limit
Internal torque
reference
Refer to torque limit setting
via constants and analog input
Speed controller
(ASR)
Priority
circuit
+
+
+
−
