Rockwell Automation 1336E IMPACT Adjustable Frequency AC Drive User Manual V 1-4.XX - Manual (Page 374)

B-36 Control Block Diagrams
Measuring the Inertia
To measure the inertia, the speed loop auto-tune test:
1. Applies the amount of torque specified in Autotune Torque
(parameter 164) to the motor.
2. Ramps the speed up to the speed specified in Autotune Speed
(parameter 165).
3. Decreases the speed down to 0.
4. Measures the slope of the increase and decrease to determine the
inertia.
Once the torque is applied, how the test measures the inertia depends
on whether bit 10 of Bus/Brake Opts (parameter 13) is set.
If bit 10 is set, the speed is ramped down to 0 after the motor reaches
the speed specified in Autotune Speed. At the same time, the torque
becomes a negative value and remains negative until the speed
reaches 0. This is shown as:
If bit 10 is not set, the speed coasts down to 0 after the motor reaches
the speed specified in Autotune Speed. The torque also becomes 0 at
this point. This is shown as:
file: Application
group: Bus Reg/Control
Speed
Time
Autotune Speed
(parameter 165)
Dwell
Time
Slope used to find inertia
0
0
Torque
Time
Autotune Torque
(parameter 164)
Dwell
Time
0
Autotune Torque
(parameter 164)
With a brake:
Speed
Time
Autotune Speed
(parameter 165)
Dwell
Time
Slope used to find inertia
0
0
Torque
Time
Autotune Torque
(parameter 164)
Dwell
Time
0
With no brake:
0