Calibration of Encoders not working - El. field value always 1 after calibrating
  • Hello,

    the short story: If I press CALIB.EL FIELD the gimbal starts the calibration by moving each motor. If it is ready the "El field" value is always 1. The stabilization is not working any longer if the gimbal is moved.

    the long story: (I'am working with Alexmos Gimbals since 2013. I have a lot of experience. My gimbal is always perfect balanced and calibrated. It is working fine if the encoders are not activated. I helped a lot of people with my youtube videos. But now I cannot do anything to get the encoders working.)
    So I will explain you what I am doing with my new BaseCam SimpleBGC 32-bit Extended Controller from iflight and my AS5048A Magnetic Encoder connected via PMW. I am using the latest 2.63b0 encoder firmware.
    I do what is written in the encoders manual. The gimbal is balanced, PIDs are calibrated, poles are correct, follow mode and RC are disabled, the calibration values in "Encoder" tab are zero. If I press CALIB.EL FIELD the gimbal starts the calibration by moving each motor. If it is ready the "El field" value is always 1. And the stabilization is not working any longer if the gimbal is moved.
    But I cannot find any other calibration problems. The blue ball on the angle panels is in the middle in neutral position - correct. The power indicator is zero in neuitral position. If I press one axis the power indicator goes to maximum - correct. I if press one axis a little bit more the motor jumps to a new unstable position an the blue ball goes to its limits - incorrect, no stabilization.

    My big question is: What am I doing wrong? And why is the El. field value always 1?

    I found out that the stabilization works a tiny bit better if I set the EL. field value for example to 13.000 for all three motors. So the encoders seem to work. But the calibration is not working at all.

    I encountered a second problem with the encoders. If all three encoders are plugged into the Controller and the LiPo is plugged in too, the Controller is only flashing but not turning on. If I put in the USB connetion as well it is turning on normally.
    So has the board a power problem? If I unplug one of the encoders, the controller is turning on normally too.

    Do you have any sugesstion?

    Regards, junk.box
  • Hello,
    1. Check that each encoder provides correct information. In the "Monitoring" tab check the "ENC_RAW_xx" variable. Especially its linearity: ensure it gives 16384 units per full turn or proportional value in the 40-degrees area around the neutral position.
    2. check the "numer of poles" parameter.
    3. The the "gearing ratio" field after calibration is finished. It should be close to 1.0 (+-0.05 is acceptable).
    4. To exclude the version of a bug in firmware, try the previous stable release 2.6x, that worked on thousands of gimbals without problems.

    Regards, Aleksey.
  • Thanks for your answer. I will check it. But I remember that I could never click on the "ENC_RAW_xx" variable. And I saw errors on all three encoders. But I am shure that they are plugged in correct.

    Regards, junk.box
  • Hello,
    I checked it. All ENC-RAW_xx variables are always 0. And I have the same read errors on all three encoders. But the cable connection is correct. Do you have any suggestion? The encoders are all new and came with different iflight motors.

    Regards, junk.box
  • I can advise only to check the wiring - did you connect all properly? If you have oscilloscope tool, you can ensure that there is a PWM signal coming from encoder.
  • I am shure that the wiring is correct. But I will double-check an write again.
  • Please give a link to motors and how you connect them. Which version of firmware is loaded? I remember it was the old bug related to PWM encoders. Try to test it with the latest beta 2.65b7 where it is corrected and there are no known bugs related to encoders.
  • I am using the iflight Motors GBM 8108-90T (http://www.iflight-rc.com/ipower-motor-gbm8108-90t-brushless-gimbal-motor-with-as5048a-encoder-compatible-with-slipring-423.html).
    But now I found a big mistake. You are wright: The wiring was wrong. The encoders have black (GND) and red (+5V) cables. My SimpleBGC Extendet board came with black and red cables, too. But the red cable is GND and the black is +5V.
    I soldered red to red and black to black.
    Do you think, that all encoders are gone now because of the wrong polarity?
  • HI
    Gimbal without encoders working well. But when I try setup encoders all motors start shaking very hard.And few second later i got message "Emergency stop: Enooder calib. failed:wrong number of poles or inversion" All motors have 28 poles one motor mark invert. 2 times i made an eeprom reset and stell the same problem.
    screen shot http://tinypic.com/r/e1deeu/9
  • Hi,
    I know this error. It came up some time if my stabilisation was not very good. I think it don't has to do anything with your poles or inversion.
    Have you checked your encoders in the monitoring tab or debug? Are they working without errors?
  • Hello alexmos,

    do you know if the encoders get broken if the +- polarity is wrong?
  • OK,

    It was my fault. I got a new encoder from iflight. It works without any problems. So my conclusion: The encoder breaks immediately if the polarity is wrong.
    So please keep in mind to check the marking. I have to solder black to red and red to black for correct polarity. Don't trust the cable color.