Probing

Add a QPushButton named probing_enable_pb and if it is found it will be set as a toggle button. The button will only be enabled when the machine is homed and not running a program.

When the probing_enable_pb is toggled OFF any widget with an object name that starts with probe_ will be disabled.

When the probing_enable_pb is toggled ON the widgets that start with probe_ will be enabled. In addition spindle controls will disabled, spindle speed set to 0, run controls will be disabled, MDI controls will be disabled.

QPushButtons with an objectName that starts with probe_ and configured as a MDI Button to launch the probing subroutines will be enabled when probing is enabled and disabled when probing is disabled.

You can create a HAL Spinbox to use in your probing subroutine. Set the objectName to start with probe_ and it will be enabled and disabled with the probe buttons.

If you’re using a touch screen add a Dynamic Property name input and set the value to touch.

Example

A minimal example is in the Flex Examples in the Features directory.

To run the example close the E Stop, turn Power on, Home all, then togggle the Enable button. When probing is enabled many other controls are disabled including the spindle.

To test the probe routine press the Probe X Plus button and the X axis will start to move in the positive direction. If you do nothing when the Search Distance is reached you will get an error that the G38.2 move finished without making contact.

Press the Probe X Plus button again and after it starts to move press the Probe Trip button, the X axis will back off the Backoff Distance and start to move in the positive direction again. Pressing the Probe Trip button will end the probe simulation. The debug information will show up in the Information window.

Subroutine

The probe subroutine uses the values from the Probe Settings spin boxes. To use the values you need to make the spin box a HAL pin. See the Spinbox example in the HAL section.

The subroutine is located in a directory called subroutines that is in the configuration directory. In the ini file in the [RS274NGC] section the following entry sets the path that LinuxCNC looks for subroutines. Notice the leading ./ specifices that the path to the current directory is where the subroutines directory is.

SUBROUTINE_PATH = ./subroutines

The example files used are the following and notice that the xplus.ngc is in the subdirectory subroutines.

├── main.hal
├── parameters.var
├── parameters.var.bak
├── postgui.hal
├── probe.ini
├── probe.ui
├── README
├── sim_axis_probe.ini
├── subroutines
│   └── xplus.ngc
└── tool.tbl

The subroutine is a normal LinuxCNC subroutine. The magic is how you get the values from HAL pins with #<_hal[pin_name]> where pin_name is the actual pin name in HAL.

(filename xplus.ngc)
(HAL pins #<_hal[pin_name]>)
(G90 absolute distance mode G91 incremental distance mode)
o<xplus> sub
        (msg, xplus subroutine)
        G20
        ; initial search
        G91 G38.2 F#<_hal[flexhal.search-speed]> X#<_hal[flexhal.search-distance]>
        ;5061-5069 - Coordinates of a G38 probe result (X, Y, Z, A, B, C, U, V & W)
        (debug, Probe Contact at #5061)
        ; back off using #5061 to compensate for over travel on the probe
        G90 G0 X[#5061-#<_hal[flexhal.backoff-distance]>]
        ; final probe at latch speed
        G91 G38.2 F#<_hal[flexhal.latch-speed]> X[#<_hal[flexhal.backoff-distance]> + 0.02]
        (debug, Probe Contact at #5061)
o<xplus> endsub
M2

Looking at the Halshow window which pops up when you press the Show HAL button you can see the flexhal pin names for each spin box and for the Probe Trip button. Also notice that the Probe Trip button is conneced to a signal which is connected to motion.probe-input in the postgui.hal file.