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encoder detection

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RSR
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encoder detection

I tried to detect encoder parameters on a 8-pole servomotor with 80A (rms?) rated continuous current.  Using VESC 6 and VESC-tool free menu: Motor Parameters --> FOC --> Encoder --> Detect Encoder.  Clicking on "Start Detection" runs motor first slowly (relaxed steps), then in more sudden steps.  Results are plausible at 10A current (in my case it detected Offset 103.4,  Ratio 4.0, Inverted), but results are not consistent when increasing current.  Increasing to 25A and I get offset 115.8, ratio 4.0, and next time 187.2, ratio 5.0,   When using 30A, then the stepping continues for very long time. 

I tried to check the offset via this method:  Set sensorless ERPM to high value, adjust resolver offset to get lowest current at max speed.  Result: lowest current at 100-110 deg offset.

What can be reason for fail and how to to check?   I suspect high current might induce noise on encoder signal.  

benjamin
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Joined: 2016-12-26 15:20
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What kind of encoder are you using? If it is an A, B, Index you also have to configure the amount of encoder counts.
RSR
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Using AMT capacitive with A,B,index.   yes, I have configured the resolution

Benjamin Mahony
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Joined: 2018-01-09 02:45
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Your getting much further than me, sorry to hijack your thread but I just happy to se people discussing encoders as they are not very popular over on the eskate forums. 

Sadly I can't get the an optical ABI encoder to auto detect in vesc tool wizard.  I have checked the encoder signals at the board using an oscilloscope and all looks nice, clean, square and full swing.  When I run auto detection, the motor pulses around in 18 degree steps for a full revolution in one direction, switches direction and then either just keeps stepping for ever or drops out comms, both faults require power cycle to recover comms.   Any suggestions?

I would like to spin the motor by hand and see if the Vesc can see the encoder signals, anyway to test this? 

FOCBOX (HW4.12, FW3.34) and Vesc tool.  Hall sensor filter components removed and 0ohm Resistors fitted