NOOB to Duet has wiring questions!



  • Greetings and Salutation Duet Peeps!

    Working on a retrofit on a HUGE Cartesian machine. Started out using the 8 bit "A Word" controller and am making the jump to the land of 32bit.

    I am using external Motor Drives and External Relays for Heating of Bed and Extruder. The connections drawing of the Duet is pretty good however, it would be INCREDIBLY helpful if there was a drawing that showed actual devices connected.

    In other words... I am having trouble determining where to connect the output signal for the heaters and the motor drives. As far as the Heat goes, I am thinking I can use the existing E0 Heater output (I'm guessing it's 12VDC) and connect to an external SSR. Same goes for the Bed... use the existing HEATED BED outputs to drive an external SSR. Does this sound like a good idea or is there someplace else I can pick up the Heater signals?. While we are talking about these outputs. Can someone please explain the nomenclature VIN. On DC outputs, I am used to seeing Positive + and Negative -. Not really sure what VIN & E0- is trying to convey-Help please!

    Now, let's talk about those motor connections! I understand that I have to pick up these signals from the expansion header. However there does not seem to be outputs for X (Drive 0), Y (Drive 1) & Z (Drive 2). Expansion Header outputs start at Drive 5. Read something about using an M command to remap- OK but I have not yet found it explained anywhere that if you use external Drivers that you just lose Outputs 0 thru 2. Is this the case?

    Basically my Drivers are looking for a good old fashioned Dir +, Dir -, Step + & Step -. I am assuming that the GND on the Expansion Header will be used for all my Negative - signals. Is this correct? Also are Expansion Header Ground Pins 2, 30 & 42 all tied together? (I guess I could just put a wiggy on it but, too late I've already asked LOL.

    I have more questions but I'll hold short here and hopefully someone smarter than me will jump in and help light my way! Thanks in advance!


  • administrators

    @da-sid-mon said in NOOB to Duet has wiring questions!:

    In other words... I am having trouble determining where to connect the output signal for the heaters and the motor drives. As far as the Heat goes, I am thinking I can use the existing E0 Heater output (I'm guessing it's 12VDC) and connect to an external SSR. Same goes for the Bed... use the existing HEATED BED outputs to drive an external SSR. Does this sound like a good idea ...

    Yes.

    While we are talking about these outputs. Can someone please explain the nomenclature VIN. On DC outputs, I am used to seeing Positive + and Negative -. Not really sure what VIN & E0- is trying to convey-Help please!

    VIN is positive, E0- is negative. What we are trying to convey by the labelling is that the Duet switches the negative output.

    Now, let's talk about those motor connections! I understand that I have to pick up these signals from the expansion header. However there does not seem to be outputs for X (Drive 0), Y (Drive 1) & Z (Drive 2). Expansion Header outputs start at Drive 5. Read something about using an M command to remap- OK but I have not yet found it explained anywhere that if you use external Drivers that you just lose Outputs 0 thru 2. Is this the case?

    You don't lose them, they are still available (using the Duet's own drivers). For example, you can use them to drive extruders.

    Basically my Drivers are looking for a good old fashioned Dir +, Dir -, Step + & Step -. I am assuming that the GND on the Expansion Header will be used for all my Negative - signals. Is this correct? Also are Expansion Header Ground Pins 2, 30 & 42 all tied together? (I guess I could just put a wiggy on it but, too late I've already asked LOL.

    Have you read https://duet3d.dozuki.com/Wiki/Using_external_stepper_motor_drivers ? You may find this breakout board helpful https://www.duet3d.com/DuetAddons/Expansion_Breakout.



  • DUUUUUUUUUUUDE!! THANK YOU VERY VERY MUCH- That's enough to get me going! I did read that article but thought I could get by without the expansion boad- Change of plan now and I ordered one. I'll circle back and let you know about my success/failure rate LOL!


 

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