Section 5
Special Functions
Special Functions 5-1
MN1269
Current (Torque) Mode
The “LD” can be configured for current mode operation by moving jumper P6 to its right
position (pins 1 to 2). This current mode operation is useful in applications where
commanded motor torque must be proportional to a voltage at the signal input. Since
torque is proportional to motor current, constant current must be provided to the motor to
develop constant torque. The current mode operation differs from standard operation in
that the velocity loop is basically disabled (gain is reduced from 6000 A/V to
approximately 6 A/V). The remaining current loop controls the output current proportional
to the input voltage (VCS).
Typical applications requiring current mode operation are:
Web controls
Brake applications
Bolt tightening
Current mode operation is useful if a programmable motion controller is precisely
controlling the velocity loop. In this configuration tachometer feedback is not required.
To convert a velocity control amplifier to a current amplifier (Refer to Figure 5-1).
1.
Move the P6 jumper to its right position (pins 1 to 2).
2.
The T pot must be rotated fully counter–clockwise.
3.
The S pot should be set fully clockwise.
Note: if the A pot is used, set full clockwise and the S pot counter–clockwise.
Figure 5-1 Servo Control Card
Servo Systems Co. • 115 Main Road • P.O. Box 97 • Montville, NJ, 07045-0097
(973) 335-1007 • Toll Free: (800) 922-1103 • Fax: (973) 335-1661
www.servosystems.com
