Custom Axis Jog and Homing options



  • Hey group, I'm using the Duet Wifi for to build a house printer. One of the motor axis is used for a rotary that sprays concrete. I need to set up the interface where I can turn on the rotary (z-axis) and it stays on while I jog other axis around. This needed for testing and other functions. I've been turning on the rotary by clicking the home z button and changed the homez file to a ridiculous travel amount to keep it on. The problem I'm having is that I need to jog the other axis (x and Y) around while the rotary stays on. Does anyone no any ways I can do this? Also I need to turn off the rotary when needed...


  • administrators

    Currently the firmware doesn't have a facility to perform movements that are not synchronised between all the axes.

    Have you considered using a DC motor for the concrete sprayer, perhaps connected to a spare heater output (don't forget to add a flyback diode!), and controlling its speed by PWM using M42? That might work if the speed control doesn't have to be precise.



  • @dc42 Yeah I have been thinking about that. Someone just informed me that I can actually use a stepper motor with PWM like a brushless motor. This might be more ideal for me because I already have the Nema34 and machined parts to mount the nema34. I'm not sure if this would work but I might give it a try.



  • @dc42 Hey I bought this Nema 34 brushless motor and driver off Amazon. https://www.amazon.com/gp/product/B07H29S6DS/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

    Do you think I can wire the fan pins to the enable of the driver to turn it on with the fan control?

    Also is there a way to rename the jog buttons (X.1, X1.)?


  • administrators

    @shane77304 said in Custom Axis Jog and Homing options:

    @dc42 Hey I bought this Nema 34 brushless motor and driver off Amazon. https://www.amazon.com/gp/product/B07H29S6DS/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

    Do you think I can wire the fan pins to the enable of the driver to turn it on with the fan control?

    Wow, that's expensive!

    Do you have a DueX2 or DueX5 in your system, or a stepper motor expansion breakout board? If so then the easiest way to control that motor driver would be to feed one of the servo outputs into its AVI input, and use a common ground between the Duet and the motor driver.

    Also is there a way to rename the jog buttons (X.1, X1.)?

    In Duet Web Control you can configure the step size, see the User Interface page.


  • administrators

    @shane77304 said in Custom Axis Jog and Homing options:

    Also is there a way to rename the jog buttons (X.1, X1.)?

    See
    https://duet3d.dozuki.com/Wiki/Duet_Web_Control_Manual#Section_Adjusting_movement_amounts

    assuming you want to change the step size.



  • @dc42 Yeah it was pricey but my customer is paying for it. It's going on a 3 axis robot arm thats attached to an electric crane to print houses. We're just in proof of concept stage right now. I'm using the breakout expansion header. I'm just trying to use the Duet Wifi to turn on the rotary which will be ALWAYS ON, then run jog the print around while the rotary stays on and cycle through a series of macros. Think of the rotary as a giant fan but instead of blowing air it sprays concrete. It would be nice if I can make a button on the web interface to turn on the rotary and have it stay on while I execute other macros and jog the other three axis around without the rotary stopping. After we get a proof of concept we'll get more money to develop it further. Long term I'm going to need a CAN bus to interface with the electric crane to automate the crane motion. Do yall do custom boards by any chance. I heard that the next Duet Wifi board coming out will have a CAN bus connection.


  • administrators

    Yes the next generation Duet will support a CAN-FD bus. We have made custom boards for several customers.



  • @dc42 Ok so I need to wire one of the Duet servo outputs to the brushless motor's driver AVI and use a common ground between the Duet and the motor driver. So according to this illustration
    alt text
    the servo connectors are the same pins as used for the stepper endstops? Or should I be wiring to the expansion header as stated in the "Using servos and controlling unused IO pins" documentation? Also do think I still need the 220uF capacitor on the 5v rail for back emf?


  • administrators

    No, the servo pins use the same output pins as the extruder heaters. So disable the corresponding heater using M307 (e.g. to disable heater 7 aka E6 aka PWM_5, use M307 H7 A-1 C-1 D-1), then use the corresponding logical pin number in the M280 command. For heater outputs, the logical pin number is equal to the heater number; so M280 P7 Sxx would control PWM_5.

    You don't need the 200uF capacitor, that is needed for large servos that are powered from the 5V pin on the servo connector.


 

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