8.3 Lua Extensions

OpenDRO extends Lua with a number of built-in objectsthat make it easy to get status information and control the behavior of OpenDRO.  These extensions are summarized below. 

8.3.1 User Functions

OpenDRO supports up to ten user functions that are started from the DRO keypad.  The user functions are identified by functions at global scope named 'user0' through 'user9'.  After creating a user function, you run it by pressing the FUNC key twice followed by the number.  For example, suppose you create a user function to beep for 500ms.  Enter the function in the shell as follows:

OpenDRO> function user1() machine.beep(500) end

Now press FUNC-FUNC-1 and the DRO will beep (assuming you have the beeper on).  Note that on the second press of the FUNC key, the OpenDRO will prompt for the user function to execute.  If after making a selection the function has a run-time error, OpenDRO will display an error message on the display which you can clear by pressing any key.  You can then go back and correct your user function or try running it from the shell by typing the function name and empty parentheses (i.e. 'user1()').

8.3.2 Auto-Execute Script

OpenDRO can automatically execute a Lua script on boot up.  This script is stored in the non-volatile memory on the DRO and is used to initialize user functions, load programs off of the SD card, or to do anything else you like.  On the DPU-550, this is the only place to store permanent Lua code.  For the DRO-550, one can execute Lua scripts from the SD card in addition.  The auto-execute script is written by the luash.execwr() function and read by the luash.execrd() function.  See the OpenDRO object reference below for more information.

8.3.3 OpenDRO Types

The data types listed below are used by the OpenDRO object reference that follows this section.  These are not meant to represent official Lua data types and are simply used to clarify the expected type and range for the parameters passed to and returned from the OpenDRO objects.

• FLOAT - A decimal floating point number.  For example, -1.23 or 5.78555.
• INT - An integeral positive or negative number.
• BOOL - A boolean value.  In Lua, 'nil' or 'false' are logically false, 'true' or any other value is logically false.
• STRING - A textual string encapsulated inside of single or double quotes.  Most strings used by OpenDRO are not case sensitive.
• TABLE - A Lua table which can represent an indexed array or an arbitrary set of data.
• FILE - A string identify the complete path to a file on the SD card.  Either forward slash '/' or backward slash '\' may be used as directory separators.  The file path is not case sensitive.
• AXIS - A string or number identifying an axis.  Mill axes are identified by 'X', 'Y', 'Z', 'W', or 'C' or by the numbers 1 through 5, respectively.  Lathe axes are identified by 'X', 'Z1', Z2', 'W', or 'C'.
• LINE - A number from 1 through 3, or 1 through 5 if an LCD-200 is attached, that identifies a display line.  Lines 1 through 3 are displays X, Y, and Z, respectively, on the main DRO display.  Numbers 4 and 5 identify display lines W and C, respectively, on the LCD-200 display.
• MENU - A number from 1 through 3 that identifies the top, middle, or bottom menu line on the display, respectively.
• SCALE - A number from 1 through 5 that identifies a scale.

8.3.4 OpenDRO Objects

This section lists the OpenDRO objects added to Lua that enable you to control and report various aspects of its operation.  The tables following each object list the functions available inside of the object.

axis

config

display

func

keypad

luash

machine

mem

scale

sd

system

trace