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TB331 Rev1 – Instructions for Using a scale as a DRO W/Acorn
Intro
The Acorn can accept one scale or encoder input By default the encoder input is assigned to axis 5 in CNC12 To use a
scale as a DRO we need to assign axis 5 as a manual axis axis 5 Motor Revs per In/mm to 1 and axis 5 steps per rev to the
number of steps per inch or mm of the scale
Navigate to Motor Menu
In CNC12 Navigate to the Motor Parameter Menu F1 Setup F3 Config F2 Mach F2 Motor
Set Axis 5 Label to M
Under the Label column for axis 5 toggle the Select the N and set it to M
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TB331 Rev1 – Instructions for Using a scale as a DRO W/Acorn
Refer to Imperial or Metric below depending on your application
Imperial
The Resolution of scales are measured in mm per step and can be found on the scale or in the documentation CNC12 uses
Steps per inch To convert use this formula 25 4 / Resolution of scale For example 25 4/ 001mm = 25400 Steps per inch
Set Axis 5 Motor rev/in to 1
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TB331 Rev1 – Instructions for Using a scale as a DRO W/Acorn
Set Axis 5 Motor Steps/rev to the number from the above formula
Press F10 Save and return to home screen for changes to take effect
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TB331 Rev1 – Instructions for Using a scale as a DRO W/Acorn
Metric
The Resolution of scales are measured in mm per step and can be found on the scale or in the documentation CNC12 uses
Steps per mm To convert use this formula 1 / Resolution of scale For example 1/ 001mm = 1000 Steps per mm
Set Axis 5 Motor mm/rev to 1
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TB331 Rev1 – Instructions for Using a scale as a DRO W/Acorn
Set Axis 5 Motor Steps/rev to the number from the above formula
Press F10 Save and return to home screen for changes to take effect
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TB331 Rev1 – Instructions for Using a scale as a DRO W/Acorn
Scale Requirements Verify Pin out in your scales documentation!
Encoder Output Encoders must have RS422 type differential quadrature outputs with A B and Z channels to work with the
Acorn
The outputs have additional voltage level requirements described in the table below
Wiring Code Wire the encoder according to the diagram and the table shown below Refer to the encoder manufacturer’s
documentation for the wiring color code
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TB331 Rev1 – Instructions for Using a scale as a DRO W/Acorn
Identifying Resolution
The resolution of the scale will be marked on the scale and/or listed in the documentation
Document History
Rev1 Created on 2024 05 30 by #493
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