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DRV2605L: Diagnostics and Auto calibration modes both fail

user5282848
Prodigy 20 points
Part Number: DRV2605L
Other Parts Discussed in Thread: DRV2624, DRV2625

Hello,

I'm trying to use the DRV2605L to drive a C2-tactor LRA (link).

I have successfully used the same system (Arduino + Adafruit DRV2605L board) to drive a C10-000 LRA from Precision Microdevices.

I've adjusted the Rated and Overdrive voltages (1.5Vrms and 2.5V) as well as the resonance frequency (270Hz) according to the technical specifications of the C2-tactor.

But both "diagnostic" and "autocalibration" modes now flag an error, which did not occur with the same code when driving the other LRA.

I've tried several values for the SampleTime, BlankingTime, IDissipationTime and ZCDetTime, but always get the same error.

Any idea about what is causing the error? Many thanks in advance!

François

// Configuration values before diagnostic and autocalibration
uiBrakeFactor = 2
uiLoopGain = 2
uiBEMFGain = 3
uiRatedVoltage = 61
uiClampVoltage = 117
uiAutocalTime = 2
uiDriveTime = 13
uiSampleTime = 1
uiBlankingTime = 2
uiIDissTime = 3
uiZCDetTime = 0

// Registers before diagnostic and autocalibration
0x1A : 0x10101011
0x1B : 0x10001011
0x1C : 0x11011011
0x1D : 0x10100000
0x1E : 0x00100000
0x1F : 0x10000000
0x20 : 0x00110011
0x21 : 0x11100010
0x22 : 0x00101000
Status = 0x11100000

Execution Log:
 
Diagnostic mode ..... done
No motor connected or motor dysfunction (status = 0x11101100)
Calibrating ..... done
No motor connected or motor dysfunction (status = 0x11101100)

// Values of populated registers after calibration
uiBEMFGain = 3
Autocal compensation = 12
Autocal EMF = 108

  • 0
    TI__Genius 10512 points
    Hi Francois,

    I just read a little information about that actuator, but I haven't ever used one. From the information, it looks like the resonance peak is between 200-300Hz. This makes me think that it may not be a high-Q actuator, but rather it is optimized for a wideband of frequencies. This can cause issues with our driver because out driver is designed for high-Q systems. If you could run a frequency sweep, the results can confirm this theory.
    Alternative way to drive the LRA is using the open-loop mode.
  • 0 in reply to Kelly Griffin
    Prodigy 20 points

    Hi Kelly,

    thanks for your answer, this could explain the problem. According to the technical documentation from EAI, the mechanical Q-factor (determined on the peak to peak displacement vs frequency curve) is around 10. I think that the electrical Q-factor is also around 10, considering that the EMF is proportional to the speed.

    Is au Q-value of 10 enough for allowing a closed-loop control with the DVR2605L?

    Anyway, I will try using the open-loop mode. The problem is that I was using the PWM control mode for switching the LRA on and off...

    Regards,
    François

  • 0 in reply to user5282848
    TI__Genius 10512 points

    Hi François,

    That Q-value should work with our driver. One thing you can try is using the DRV2625/DRV2624 to run auto-calibration. There is more diagnostic information reported back. It is possible that the BEMF voltage is out of range. This newer driver also has a more robust algorithm and may be able to drive the LRA.
    You should still be able to use PWM input in open-loop mode. But this can effect the vibration performance.