External drives limited at 25Khz



  • Hello,

    First of all, let me define my setup:

    The other items in my setup are irrelevant to my problem.

    I have the config file configured according to posts that I have read on the forum that have a similar setup to mine, which is T3.3:3.3:6:0, and it works up to a point and that point seems to be right around 25kHz for each motor. Any feed that I try to give above that results in lost steps.

    So, I hooked up the output from E3 port to an oscilloscope (Hameg HMO3004) to find out that when I cross the 25kHz boundary, the pulse lengths keep varying between 3.3us and 1.24us, which explains the lost steps as my drive does not accept anything lower than 2.5us but, what is interesting is the pulse-to-pulse time is calculated correct. So, when I increase the feed, lets say, to get a 33.3kHz motion, the pulse length and the gap in between the pulse is correctly set at 33.3kHz but, the pulse length is varrying between the set 3.3us to 1.24us, which baffles me.

    What could be causing this?

    Thank you.



  • I have also uploaded a ss from Saleae Logic analyzer, you can see some of the pointers and the measurements that I took from the signal on the right side.
    0_1555951406244_logic.jpg


  • administrators

    Which firmware version are you running?



  • Firmware is 2.02RC5(RTOS) (2018-11-28b1)



  • @byazici said in External drives limited at 25Khz:

    Firmware is 2.02RC5(RTOS) (2018-11-28b1)

    you should update to 2.02 at least. there was a bug that would impact long running prints.



  • OK, so, I have upgraded to the latest 2.03beta3 (2019-03-25b6) firmware. The problem continues...

    Here, the signal is at 25kHz:

    0_1556008608949_SCR02.PNG

    Here the signal is at 27kHz, where you can see the 1.36us signal, which creates a problem:

    0_1556008646914_SCR03.PNG



  • Here is the config file:

    ; Configuration file for Duet Maestro (firmware version 1.21)
    ; executed by the firmware on start-up
    ;
    ; generated by RepRapFirmware Configuration Tool v2 on Sat Apr 13 2019 13:22:32 GMT+0300 (GMT+03:00)

    ; General preferences
    G90 ; Send absolute coordinates...
    M83 ; ...but relative extruder moves

    M667 S1 ; Select CoreXY mode

    ; Network
    M550 P"My Printer" ; Set machine name
    M552 P0.0.0.0 S1 ; Enable network and acquire dynamic address via DHCP
    M586 P0 S1 ; Enable HTTP
    M586 P1 S0 ; Disable FTP
    M586 P2 S0 ; Disable Telnet

    ; Drives
    M569 P0 S1 T3.3:3.3:6:0 ; Drive 0 goes forwards
    M569 P1 S1 T3.3:3.3:6:0 ; Drive 1 goes forwards
    M569 P2 S1 ; Drive 2 goes forwards
    M569 P3 S1 ; Drive 3 goes forwards
    M584 X5 Y6 Z2 E3 ; Apply custom drive mapping
    M350 Z16 E16 I1 ; Configure microstepping with interpolation
    M92 X100.00 Y100.00 Z1280.00 E420.00 ; Set steps per mm
    M566 X900.00 Y900.00 Z900.00 E120.00 ; Set maximum instantaneous speed changes (mm/min)
    M203 X90000.00 Y90000.00 Z3000.00 E1200.00 ; Set maximum speeds (mm/min)
    M201 X1000.00 Y1000.00 Z20.00 E250.00 ; Set accelerations (mm/s^2)
    M906 X15.00 Y15.00 Z1500.00 E800.00 I30 ; Set motor currents (mA) and motor idle factor in per cent
    M84 S30 ; Set idle timeout

    ; Axis Limits
    M208 X0 Y0 Z0 S1 ; Set axis minima
    M208 X10000 Y10000 Z400 S0 ; Set axis maxima

    ; Endstops
    M574 X0 Y0 Z0 S0 ; Set active low and disabled endstops

    ; Z-Probe
    M558 P0 H0 F120 T18000 ; Disable Z probe but set dive height, probe speed and travel speed
    M557 X8:216 Y8:316 S20 ; Define mesh grid

    ; Heaters
    M140 H-1 ; Disable heated bed
    M305 P1 T100000 B4138 R2200 ; Set thermistor + ADC parameters for heater 1
    M143 H1 S280 ; Set temperature limit for heater 1 to 280C

    ; Fans
    M106 P0 S0 I0 F500 H T45 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned on
    M106 P1 S1 I0 F500 H T45 ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned on

    ; Tools
    M563 P0 D0 H1 ; Define tool 0
    G10 P0 X0 Y0 Z0 ; Set tool 0 axis offsets
    G10 P0 R0 S0 ; Set initial tool 0 active and standby temperatures to 0C

    ; Automatic saving after power loss is not enabled

    ; Custom settings
    M918 P1 ;initialize display
    M564 H0



  • Think I found it, correct me if I am wrong:

    I changed M569 P0 to P5 and P1 to P6, this seems to have fixed the issue...will test


  • administrators

    @byazici said in External drives limited at 25Khz:

    Think I found it, correct me if I am wrong:

    I changed M569 P0 to P5 and P1 to P6, this seems to have fixed the issue...will test

    That's right, assuming you are using the first 2 sets of step/dir/enable signals on either the expansion connector or the expansion breakout board.



  • I guess thats because the reprap configurator has a problem, because I did select the correct board and the correct external motors 5-E2 and 6-E3 but, it still appoints P0 and P1 in the config file. I guess you might want to report that.


  • administrators

    @byazici said in External drives limited at 25Khz:

    I guess thats because the reprap configurator has a problem, because I did select the correct board and the correct external motors 5-E2 and 6-E3 but, it still appoints P0 and P1 in the config file. I guess you might want to report that.

    Thanks, we'll get that fixed.


  • administrators

    Thanks, it looks like the configtool was using logical instead of physical drives. It's fixed now.


 

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