Analyzing torque mode effects

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Due to discussion about torque control differences between IONI firmware versions 1.4 and 1.5, we made a special versions of both firmware versions to allow analytical comparison of torque output. If unexpected differences are noticed, please report us at Granite Devices support.

How to compare[edit | edit source]

Example of Tracking error on step response test with TBW and notch filter enabled
Example of Tracking error on step with TBW set to Unlimited and all other effects disabled

Analytical comparison is achieved by the means of Tracking error capture channel in Granity. This channel displays the difference between the pure unmodified user setpoint and realized actual torque. The difference scale is in millamperes.

Following parameters will modify the setpoint torque and cause the difference between actual and raw setpoint to grow:

  • Maximum peak powerMPP
  • Torque bandwidth limitTBW
  • Torque notch filter
  • Torque mode effects
  • Motor torque cogging & ripple compensation

If all effects are disabled and TBW is set Unlimited, then in the ideal case Tracking error would be straight line at zero. However, in practice some error will be there due to current sense noise and physically limited torque control bandwidth.

Guide[edit | edit source]

To run comparison in real application, connect drive with Granity and configure capture with following settings:

Capture signals
Only Tracking error
Capture controls
TSR of 500 to 2500Hz
Capture instantly
Continuously repeating catpure

Then click Start capture and run the application which uses drive in torque control mode and simultaneously observe the graph. You can do this test with 1.4 and 1.5 firmware versions to see if there is any unexpected difference.

Firmware files[edit | edit source]

Use the firmware files here to do the comparison with Tracking error feature:

Older firmware versions don't have Tracking error scope in torque mode (will display only straight line of zero value).

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