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Motor periodic noise

2018-11-16
2018-11-23
1 2 > >> (Page 1 of 2)
  • MASSIMILIANO CHERSICH

    I'm working with the standard configuration DRV8825_HW203 and a Nema 17 PG27 stepper motor.
    I've already adjusted the current as indicated in the manual (using a tester).
    Regardless of Step Mode the motor produce a periodic noise (with approx a 1s period).
    Is this something intrinsic to the motor design or could this be an indicator of a problem?
    Thanks in advance...

     
  • brownrb

    brownrb - 2018-11-16

    Hi
    You will need to be a bit more specific
    Does the noise happen when moving or not moving?
    What sort of noise?
    Is it loud?
    High pitched?
    Like an electrical buzzing one gets in one ear?
    If you can do a video with sound would be very helpful

    What is current current level set to with full steps coil power on?
    Regards
    Robert

     
  • MASSIMILIANO CHERSICH

    It is a low frequency noise that lasts about 1/10 sec and repeats once a second during fok move.
    If I remember I measured about 1/4 A during tests (full step and coil power on)...
    Tomorrow I will post a recording.

     
  • MASSIMILIANO CHERSICH

    Here is the recording. Unfortunately quality is awful. Probably the sound recorder has a noise reduction filter I was not able to deactivate... You have to turn up the volume at maximum to hear a little (from second 3:00)...

     
  • brownrb

    brownrb - 2018-11-21

    Hi
    That sounds mechanical, like a stripped gear.

    I do not think it is a driver issue or controllerissue

    Remove motor from focuser.
    Put controller and motor on a bench
    Connect to controller with USB and do same moves.
    If noise is still there then this is a motor issue.

    If noise is gone when motor free from focuser, then it is about how motor is connected to focuser. Maybe not aligned right.

     

    Last edit: brownrb 2018-11-21
  • MASSIMILIANO CHERSICH

    Here is a better recording with motor detached from the focuser...

     
  • brownrb

    brownrb - 2018-11-21

    Yes, this audio is much better

    Not a problem with motor, or controller, or driver

    This is normal
    The sound blip is caused by the following
    The computer chip - nano - is not very powerful
    It cannot do a lot of things at once
    When you tell motor to move, it moves motor
    But then a request comes to get position or update display
    So it has to stop moving
    Update display
    Then continue moving
    The update display happens around 1s intervals
    So it causes slight pause in motor moving every second
    Which is this sound

    If you turn off lcd update when moving - the slight pause will stop. and then motor will not pause during move and will sound ok

    The small pause will not cause any problem with focuser. But you decide if you want lcd update or not.

     

    Last edit: brownrb 2018-11-21
  • MASSIMILIANO CHERSICH

    Dear Robert I'm not using the LCD neither the OLED at the moment.
    Is there perhaps something I have to change in the .ino?

    //#define BLUETOOTH 1

    define TEMPERATUREPROBE 1

    //#define HOMEPOSITIONSWITCH 1

    define PUSHBUTTONS 1

    //#define LCDDISPLAY 1
    //#define ROTARYENCODER 1
    //#define INFRARED 1
    //#define BACKLASH 1
    //#define BUZZER 1

    define INOUTLEDS 1

    //#define CONTROLLERISAMICRO 1

     
  • MASSIMILIANO CHERSICH

    These are my extra settings. The "update position" check is already disabled but the noise still persist...

     
  • brownrb

    brownrb - 2018-11-22

    You can please try this test.
    Connect controller with USB cable
    Open firmware file for controller in Arduino IDE
    Open Serial Port Monitor in IDE (Ctrl+Shift+M)
    Make sure baud rate is set to 9600
    At the top, enter :62# and then click Send
    I need to know what is returned in window - it should be something like L01#

    Regards

     
  • MASSIMILIANO CHERSICH

    I can try later at home. In the meanwhile I attach my .ino file.

     
  • MASSIMILIANO CHERSICH

    The Win App is the latest, i.e. 2.1.4.6.
    In a couple of hours I will send you everything.
    Thanks a lot again!

     
  • brownrb

    brownrb - 2018-11-22

    Please download this windows app and test with focuser.
    https://www.dropbox.com/s/kyyz0zc0cwzp70q/myFocuserPro2_2_4_1_9.zip?dl=0
    Let me know result.
    Regards
    Robert
    Author myFocuserPro2

     
  • MASSIMILIANO CHERSICH

    Just to add another element: the noise is present also when moving the focuser by ASCOM driver (through an external automation software).

     
  • brownrb

    brownrb - 2018-11-22

    Yes, I have also a new ASCOM driver to test. I believe issue is in Software. The WIndows app and ASCOM driver share code base, so issue is common to both. I think you will find new win app 2419 is better.
    Regards
    Robert
    Author myFocuserPro2

    But please test with new windows app first. Please UNINSTALL old windows app using control panel first before installing new windows app.

     

    Last edit: brownrb 2018-11-22
  • MASSIMILIANO CHERSICH

    No way: also 2.1.4.9 has the same issue...
    The return of :62# command is L0#

     
  • brownrb

    brownrb - 2018-11-22

    You did uninstall 2.1.4.7 first?

    Connect focuser to computer
    Run windows app 2.1.4.9
    Enable logging (menu)
    Connect to focuser
    Add 1000 to focuser position and enter the value as new position then click GOTO Position
    Wait for move to finish
    Take screenshot of windows app and save
    Post the logfile and screenshot here

     
  • MASSIMILIANO CHERSICH

    Yes I did uninstall everything related to myfocuserpro2 first.
    Here is the screeshot and log file...

     
  • brownrb

    brownrb - 2018-11-22

    Interesting.
    Please set motor speed to fast and stepmode to full steps
    Repeat move 500 steps
    Any difference in noise??

     
  • brownrb

    brownrb - 2018-11-22

    You can try this sketch to move motor backwards and forwards. This will check if there is a fault with the motor
    It should be smooth with no pauses. Waits 2s between reversing directions.

     
  • MASSIMILIANO CHERSICH

    Full steps and speed=fast give the same result.
    I uploaded the sketch. After upload the motor start to move forward and reverse continuosly.
    The windows app cannot connect because the COM port seems to be busy (Serial Port is already connected. Please click Disconnect first, then click Refresh). I tried to disconnect the whole and to connect again with no result...

     
  • MASSIMILIANO CHERSICH

    I tried to modify the loop raising the number of iteration to 10000 and the motor does not make any noise regardless of direction of rotation ...

     
  • brownrb

    brownrb - 2018-11-22

    Hi again

    Your sound file threw me off a bit because I was thinking it was something else for a while.

    I have had both my focusers (and a number of older prototypes) on the bench since about 4am this morning. The little pauses (noise) are normal and date all the way back to the initial releases. I have them also.

    Drivers are normally built using a command/response protocol. This keeps things simple, easy to change/add and has minimal overhead. ASCOM also works as command/response protocol.

    As I explained before, the Arduino Nano is not a powerful chip.
    So the nano controls the timing when moving.
    During a move, it is necessary to poll the focuser to see if its stopped moving
    Otherwise we would have no way of knowing when it stopped moving.
    This is done periodically at 1s intervals.

    What you are hearing is the Nano briefly stopping the move, and handling the ismoving request from the windows application (or the ascom driver) every second when moving. The nano cannot do two things at once, only one or the other - so when its controlling the moving and a request comes in, the nano has to temporary stop the move, handle the request then go back to continue the move. IF it did not handle the request then the application would time out during a move and the serial comms would drop connection to the focuser.

    This does not affect the operation of the focuser other than causing that slight pause which you may find annoying. You will find its not noticed by any client program such as Nebulosity, APT, SGP, Maxim etc. It is normal behaviour for the focuser firmware.

    In practice it will have zero effect on the focusers operation.

    In short, try not to worry about the pause. Its normal, it will not harm your focuser or scope, its been like that since day 1. It is unavoidable and due to the limitation of the nano. We are asking a lot from the nano and its at its limit trying to keep up.

    Regards
    Robert

     
  • brownrb

    brownrb - 2018-11-22

    Hi
    I have put together this file which has been modified from the interrupt driven code v275 and updated to 278

    It is for minimal focuser only, no display, bluetooth etc, I do not support this but it works.

    I wrote the interrupt code versions sometime ago and when I get a chance update them, but its a low priority for me. However, no pauses.

    Regards
    Robert

     
  • MASSIMILIANO CHERSICH

    Thank you so much. Are you planning to publish a minimal ASCOM version for automated operations too?

     
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