How to set homing procedure in PlanetCNC TNG software

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This tutorial will explain how to correctly use Machine/Home  feature.

Homing procedure will reference machine axes and set machine work area.

 

First you would need to configure your machines step per unit values, motor & soft limits and limit switch inputs of controller:

How to set step per unit values in PlanetCNC TNG software

How to configure limit switch inputs of controller in PlanetCNC TNG software

How to set motor & soft limits in PlanetCNC TNG software

 

Homing procedure configuration

Homing procedure is configured in settings: File/Settings/Program Options/Home

 

 

Speed & Low:

Speed and Low are speed values of first and second axis reference moves.

First reference move will be performed at Speed value. After limit switch is activated, machine retracts for switch click distance and starts with the second reference move, but this time at Low speed value.

Make sure that Speed value is not set too high to the point where limit switch or machine could get damaged. Low value should be significantly lower that Speed value.

 

Order:

To set homing order of specified axis, select order number from drop down menu:

Direction:

To set homing direction of specified axis, click radio button of axis direction option, – or +. So, if your Y axis limit switch is mounted at the positive end of Y axis, you enable “+” for Y:

Switch Position:

Switch Position value is axis machine position at which corresponding axis limit switch gets activated. These values, to some degree, have already been obtained in How to set motor & soft limits in PlanetCNC TNG software tutorial.

For example, during Homing procedure when e.g. X axis is being referenced and its limit switch is activated, X axis will get assigned machine position value of Switch Position value.

To automatically populate all axis Switch Position values, click Copy Motor Limits button. However these values are not values of limit switch activation but previously obtained motor limit values…

 

Obtaining axis switch position values:

Slowly jog Z axis up until Z+ limit switch is hit and machine stops. Write down Z+ axis machine position.

If your X limit switch is mounted at positive end of  X axis: Slowly jog X axis in positive direction until X+ limit switch is hit and machine stops. Write down X+ axis machine position.

If your X limit switch is mounted at negative end of  X axis: Slowly jog X axis in negative direction until X- limit switch is hit and machine stops. Write down X- axis machine position.

If your Y limit switch is mounted at positive end of  Y axis: Slowly jog Y axis in positive direction until Y+ limit switch is hit and machine stops. Write down Y+ axis machine position.

If your Y limit switch is mounted at negative end of  Y axis: Slowly jog Y axis in negative direction until Y- limit switch is hit and machine stops. Write down Y- axis machine position.

 

Now insert all values that you obtained for switch positions into their corresponding field values…

 

 

Move To:

Each axis will travel to its dedicated Move To position immediately after being referenced.  These are machine position values.

 

Switch Click Distance:

This is the distance from the point where limit switch is activated and to the point when it is released.

 

 

Homing sequence:

You can execute homing procedure via Machine menu Machine/Home or left toolbar button: 

When Homing is executed, homing sequence(as set above – see screenshots) will be:

Z axis will be referenced first. Axis will move in positive direction until Z axis limit switch is activated. When switch is activated machine stops and moves to position set with Z “Move To”(Z=10mm) .

X axis will be referenced second. Axis will move in positive direction until X axis limit switch is activated. When switch is activated machine stops and moves to position set with X “Move To”(X=0mm).

Y axis will be referenced third. Axis will move in positive direction until Y axis limit switch is activated. When switch is activated machine stops and moves to position set with Y “Move To”(Y=0mm).

 

Home script file

Homing procedure uses script file. If you would like to edit script code or to have more in-depth look at the procedure itself, you can do that by opening script file.

You can access and edit script file:

In settings under File/Settings/Program Options/Scripts/Home & Measure -> Home, click button Edit Script.  Script file will open in TNG gcode editor. In order that Home script file is generated and saved in your profiles Script folder, you need to click Save button.