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Revision to Using external stepper motor drivers

David Crocker

The expansion header has support for 5 external drivers on the Duet 2 and 4 on Duet0.8.5 or Duet0.6. The pinouts for the expansion header are important to make a note of when connecting external drivers:
 
The generation 2 Duets also support two additional drivers connected to the CONN_LCD connector.
The generation 2 Duets also support two additional drivers connected to the CONN_LCD connector.
 
* [[Duet Wiring Diagrams|Duet 2 (WiFi and Ethernet) wiring diagrams]].
* [http://www.reprap.org/wiki/Duet#Wiring|Older Duet wiring Diagrams] .
 
If the drivers require no more than about 2mA @ 3V on the step, dir and enable inputs, then you can drive them directly from the expansion connector of the Duet. See the expansion connector pinouts above. Otherwise, you should use external drive ICs such as 74HCT04 to drive them. You can use the Duet [[expansion breakout board]] for this purpose.
 
The pinout for the two additional drivers supported by the CONN_LCD connector are as follows (the pins for drive 10 and its endstop input are on one side of the connector, and the pins for drive 11 are on the other side).
'''Important! External drivers must always be connected to the expansion connector of the Duet or to the CONN_LCD port.''' The 3-pin pads on the Duet near to the stepper drivers are test pads and are not suitable for connecting external drivers.
 
== Adding additionalConnecting external stepper drivers with differential inputs ==
== Adding additionalConnecting external stepper drivers with differential inputs ==
 
MostThese stepper driver modules generally have optically isolated inputs labelled STEP+, STEP-, DIR+, DIR-, ENA+ and ENA-.

If they require no more than about 2mA @ 3V on the step, dir and enable inputs, then you can drive them directly from the expansion connector of the Duet. See the expansion connector pinouts above. Connect STEP+ and DIR+ to your chosen Step and Dir pins on the expansion connector or CONN_LCD, and connect STEP- and DIR- to ground. Connect ENA+ to +3.3V and connect ENA- to your chosen Enable pin.

If your
external stepper drivers need more than 3V or more than about 2mA then you should use the Duet [[expansion breakout board]] or some other method to provide 5V differential drive signals.

== Connecting Pololu-style
drivers will want a==

These take single-ended
STEP, DIR and EN (step, direction and enable) signalsignals, for example the popular [http://reprap.org/wiki/StepStick] have the following pin out:
MostThese stepper driver modules generally have optically isolated inputs labelled STEP+, STEP-, DIR+, DIR-, ENA+ and ENA-.

If they require no more than about 2mA @ 3V on the step, dir and enable inputs, then you can drive them directly from the expansion connector of the Duet. See the expansion connector pinouts above. Connect STEP+ and DIR+ to your chosen Step and Dir pins on the expansion connector or CONN_LCD, and connect STEP- and DIR- to ground. Connect ENA+ to +3.3V and connect ENA- to your chosen Enable pin.

If your
external stepper drivers need more than 3V or more than about 2mA then you should use the Duet [[expansion breakout board]] or some other method to provide 5V differential drive signals.

== Connecting Pololu-style
drivers will want a==

These take single-ended
STEP, DIR and EN (step, direction and enable) signalsignals, for example the popular [http://reprap.org/wiki/StepStick] have the following pin out:
 
[image|408|align=center]
 
From experience, evenEven though the stepsticks are nominally 5V boards they work fine with theboards, nearly all stepper driver chips are specified for 3.3V from the Duet boards, however different StepStick clones might varyoperation too.
From experience, evenEven though the stepsticks are nominally 5V boards they work fine with theboards, nearly all stepper driver chips are specified for 3.3V from the Duet boards, however different StepStick clones might varyoperation too.
 
=== External Extruders Example ===
[image|412|align=center]
 
== Using External Drivers for X/Y/Z Axis ==An alternative to using a RAMPS PCB is to use an adapter such as this one http://hobbycomponents.com/motor-drivers/892-breakout-board-for-a4988-stepper-motor-driver. Note that the pin labelled 5V must be connected to 3.3V on the Duet, not to 5V.
== Using External Drivers for X/Y/Z Axis ==An alternative to using a RAMPS PCB is to use an adapter such as this one http://hobbycomponents.com/motor-drivers/892-breakout-board-for-a4988-stepper-motor-driver. Note that the pin labelled 5V must be connected to 3.3V on the Duet, not to 5V.
 
If your motors are rated above about 2.8A and you are using the Duet WiFi, or above about 2A and you are using the Duet 0.6 or 0.8.5, or if they need higher voltage than the Duet can provide, then you need external stepper motor drivers. These may have optically isolated step/dir/enable inputs. For example, stepper motor drivers rated at up to 4.5A using the TB6600 stepper driver chip are widely available on eBay.== Using External Drivers for X/Y/Z Axis ==
If your motors are rated above about 2.8A and you are using the Duet WiFi, or above about 2A and you are using the Duet 0.6 or 0.8.5, or if they need higher voltage than the Duet can provide, then you need external stepper motor drivers. These may have optically isolated step/dir/enable inputs. For example, stepper motor drivers rated at up to 4.5A using the TB6600 stepper driver chip are widely available on eBay.== Using External Drivers for X/Y/Z Axis ==
 
The same principle as described above for adding an additional extruder driver is usedTo use external drivers to add an external driver for a movement axis. What is also required isdrive X, Y and/or Z axes instead of the internal ones, you need to remap the X/Y/Z axis to thisthe external driver. The drive numbers are:
The same principle as described above for adding an additional extruder driver is usedTo use external drivers to add an external driver for a movement axis. What is also required isdrive X, Y and/or Z axes instead of the internal ones, you need to remap the X/Y/Z axis to thisthe external driver. The drive numbers are:
 
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