Rockwell Automation Publication PFLEX-RM003E-EN-E - January 2011 165
Detailed Drive Operation Chapter 1
minimum is to operate as a torque regulator. While operating in torque
regulation, the load decreases and the motor speeds up. Notice the torque
command has not changed. When the speed regulator comes out of saturation, it
clamps the speed and now the drive operates as a speed regulator. The “At Speed”
relay then closes.
Figure 26 - Min Spd/Trq Mode Operation
Sum Speed / Torque Mode
Configuring the drive in this mode allows an external torque input to be summed
with the torque command generated by the speed regulator. This mode requires
both a speed reference and a torque reference to be linked. This mode can be used
for applications that have precise speed changes with critical time constraints. If
the torque requirement and timing is known for a given speed change, then the
external torque input can be used to preload the integrator. The timing of the
speed change and the application of an external torque command change must be
coordinated for this mode to be useful. The “Sum Spd/Trq” mode will then work
as a feed forward to the torque regulator.
Speed Limited Adjustable Torque (SLAT) Min Mode and SLAT Max
Mode
The SLAT minimum and SLAT maximum modes are for applications that
require a smooth transition from a torque mode to a speed mode operation; for
example: web handling, center winders and center unwinders where the drive is
normally following a torque reference, but a break or slippage could occur.
Direction of the applied torque and direction of the material movement
determine whether SLAT minimum or SLAT maximum mode should be used.
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