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Rockwell Automation Publication 2198-UM002E-EN-P - February 2018
Appendix D
Motor Control Feature Support
Table 161 - SLAT Operation When Motion Polarity Is Inverted
SLAT Min Speed/Torque
SLAT Min Speed/Torque is a special mode of operation primarily used in web
handling applications. The drive typically operates as a torque regulator,
provided that the TorqueTrim attribute is less than the torque output due to
the velocity regulator's control effort. The drive can automatically enter
velocity regulation based on conditions within the velocity regulator and the
magnitude of the velocity regulator's output relative to the torque reference.
When used for SLAT control, an application dependent VelocityCommand
value is applied to the drive via an MAJ instruction (2198-
xxxx
-ERS3 drives,
firmware 7.001 or later) or MDS instruction (2198-
xxxx
-ERS4 drives,
firmware 9.001 or later). An application dependent TorqueTrim value is also
applied via cyclic write. Under normal operation, VelocityCommand is set to a
level that results in the velocity regulator's control effort becoming saturated
when the motor's speed is mechanically limited. The TorqueReference value
equals the TorqueTrim value, resulting in a positive VelocityError value.
Should the mechanical speed limitation be removed (example: web break), the
motor accelerates and VelocityError becomes negative. At this time, a forced
transition to velocity regulation occurs, and the motor's speed is regulated to
the VelocityCommand attribute.
The axis remains in velocity regulation until VelocityError exceeds
SLATSetPoint for a time specified by SLATTimeDelay. At this point, the axis
returns to operating as a torque regulator.
Figure 176 - SLAT Min Speed/Torque
See the Integrated Motion on the EtherNet/IP™ Network Reference Manual,
publication
, for more information on SLAT attributes.
Velocity Command
Motion Polarity
SLAT Configuration
Positive (clockwise)
Normal
Min
Inverted
Max
Negative (CCW)
Normal
Min
Inverted
Max
Select Minimum of Velocity Loop Output
or Torque Command
(speed control is OFF)
Select Velocity Loop Output
(speed control is ON)
Velocity Error < 0
Velocity Error > SLAT Setpoint for SLAT Time