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gScript Documentation
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gscript.md

gScript (Gantry Script) Documentation

gScript is an interpreted language similar to assembly. A gScript source code file is a plain text file with one statement per line. Statements are executed in sequence from top to bottom. A statement has the form

COMMAND ARG0 ARG1 ... ARGN

COMMAND must be one of the build in commands as specified below. Arguments can be of various forms, including numeric and string literals, variables, or references to memory. The syntax for these forms will be described below.

The gScript interpreter has memory that is split into two parts. The first is a variable table. When you reference a variable with the $VAR syntax, gScript looks into the variable table to either read or write to that variable. Whether a read or write occurs depends on the command. Trying to read from a variable that has not been initialized will result in an error. The second part of memory is called Main Memory. It consists of an array of memory cells that can be accessed with bracket syntax, e.g. [10] to access the cell at address 10. The bracket syntax can also be used in conjuntion with variables. This is accomplished via the syntax [$var].

Comments are indicated with a #, with all characters after it being ignored.

# This whole line is a comment
ADD $res 12 -6  # This a comment sharing a line with a statement.

Labels

To reference specific lines of code, for example when using a GOTOIF, Labels can be used. The syntax for labels is the following:

@LABEL COMMAND args

The presence of a label does not effect the execution of the statement on its line.

Type System

gScript has a simple type system, supporting four types in memory (both for variables and in main memory) and five types for literals. In memory, the four supported types are integers, floats, 3d vectors, and 3d rotations. Internally, these are all stored as a four-tuple of 64-bit floats with a tag designating the type of the stored value. You can see this in the "Memory View" tab of the main UI. To access specific fields in vectors (and in fact any value), a dot syntax is supported. For example. If there is a variable called $var, one can access the y element with $var.y. It's also important to keep in mind that "integers" are stored as 64-bit floats. This could result in rounding errors for large numbers, so avoid relying on large integers being exact. For literals, in addition to the four memory types, string literals are supported for certain commands. Examples of literals are:

  • float: 10.0, 3.14E-2
  • integer: 0, 12, -568
  • 3D Vector: {12,13.7,-2}, Don't put spaces between the values!
  • 3D Rotation: {0.1,0.9,.16,0}, Again, no spaces
  • string: a_string, "a string with spaces", Quote escaping is not currently supported

But what about booleans? Boolean types are not supported in memory, but in commands that expect a boolean (e.g. GOTOIF) an argument is interpreted as false if the number in the first (the X) slot rounds to zero. Otherwise, it is interpreted as true.

Command Listing

General Commands

PASS

Does nothing. Used internally.

Format: PASS

COPY

Copies the contents of src to dest.

Format: COPY dest src

  • dest: Writable location to copy to
  • src: Readable location to copy from

PRINT

Used to print to the console on the bottom of the UI. The arguments are any readable value while format specifies how the arguments are to be printed. Supported format codes are listed in the table below

gScript Format Description
%f Equivalent to the printf format string %0.3f
%d Equivalent to the printf format string %d
%v Formats the value as a vector. {x,y,z}
%r Formats the value as a rotation. {x,y,z,w}
%b Evaluates argument as a boolean. Becomes either True or False

Format: PRINT format arg1 arg2 argn

  • format: The format string
  • arg1, arg2, argn: Readable values to insert into format string

GOTO

Used for flow control. Goes to the command at the line specified by dest. Recommend using in conjunction with labels to be robust against changing line numbers.

Format: GOTO dest

  • dest: The address of the statement to execute next. Can be a Label.

GOTOIF

Used for flow control. Goes to the command at the line specified by dest if the cond evaluates to True, otherwise proceed to the next statement. Recommend using in conjunction with labels to be robust against changing line numbers.

Format: GOTOIF dest cond

  • dest: The address of the statement to execute next. Can be a Label.
  • cond: If interpreted as True then GOTO dest, otherwise proceed to next statement.

GOTOIFN

Same as GOTOIF, except it goes to the command at dest if cond is evaluated to False.

Format: GOTOIFN dest cond

  • dest: The address of the statement to execute next. Can be a Label.
  • cond: If interpreted as False then GOTO dest, otherwise proceed to next statement.

ADD

Adds the two arguments piecewise and stores the result in dest. The type of dest is copied from arg1.

Format: ADD dest arg1 arg2

  • dest: Writable location for the result of the addition
  • arg1: Readable location for the first input to the addition.
  • arg2: Readable location for the second input to the addition.

SUB

Subtracts the two arguments piecewise and stores the result in dest. The type of dest is copied from arg1. The operation is equivalent to dest = arg1 - arg2.

Format: SUB dest arg1 arg2

  • dest: Writable location for the result of the subtraction
  • arg1: Readable location for the first input to the subtraction
  • arg2: Readable location for the second input to the subtraction

INC

Increments the first, the x, field in arg1 by 1 and stores the result in dest.

Format: INC dest arg1

  • dest: Writable location for the result of the increment
  • arg: Readable location for the value to be incremented

DEC

Decrements the first, the x, field in arg1 by 1 and stores the result in dest.

Format: DEC dest arg1

  • dest: Writable location for the result of the decrement
  • arg: Readable location for the value to be incremented

WAIT

Pauses execution for the specified number of milliseconds.

Format: WAIT time

  • time: Readable specifying the number of milliseconds to wait

FIT

Computes a position/orientation of a part in the gantry's coordinate system by comparing measured reference points with reference points defined by mechanical drawings of that part.

Format: FIT pos rot type fid_tr fid_br fid_bl fid_tl

  • pos: Writable location to store the position resulting from the fit
  • rot: Writable location to store the orientation resulting from the fit
  • type: The type of part that is being fit. Currently either BBM or HDI.
  • fid_tr: Top-right fiducial position
  • fid_br: Bottom-right fiducial position
  • fid_bl: Bottom-left fiducial position
  • fid_tl: Top-left fiducial position

Motion Commands

HOME

Moves the X,Y,and Z axes to their home positions.

Format: HOME

MOVETO

Moves the gantry to the absolute position of the vector specified by pos.

Format: MOVETO pos speed

  • pos: 3D Vector specifying an absolute position to move to
  • speed: Optional number to specify the speed of the motion in mm/s. If omitted, use the (rather slow) default speed.

MOVEREL

Moves the gantry through the displacement specified by the vector dis

Format: MOVEREL dis speed

  • dis: 3D Vector specifying a relative motion
  • speed: Optional number to specify the speed of the motion in mm/s. If omitted, use the (rather slow) default speed.

MOVESAFE

Moves the gantry to the named position pos_name. It must be one of the named positions found in safe_move_pos_data.dat.

Format: MOVESAFE pos_name

  • pos_name: A string literal for the name

GETPOS

Reads the current position of the gantry and saves it into pos.

Format: GETPOS pos

  • pos: A writable location to save the current x/y/z position

ROTATE

Rotates the gantry head by rot degrees.

Format: ROTATE rot

  • rot: The amount to rotate in degrees

GETROT

Reads the current rotation of the gantry head in degrees and saves it into rot.

Format: GETROT arg1

  • rot: A writeable location to save the current rotation in degrees

JOYSTICK

Format: JOYSTICK cam_name

Enables the Joystick. If cam_name is supplied and matches one of the cameras as specified in camera_configuration.ini, a video stream from that camera is shown in the popup window. Execution of the script will halt until the 'C' button is pressed on the joystick.

  • cam_name: The camera identification for the popup feed. If blank, no image is shown.

Vision Commands

SNAPSHOT

Fetches an image from the specified camera. If filename is specified, the image is saved to that location. Otherwise, a pop-up window will display the image until dismissed.

Format: SNAPSHOT cam_name filename

Vacuum Commands

SETVAC

Sets the specified vacuum channel to either on or off depending on the boolean evaluation of state.

Format: SETVAC chan state

  • chan: The channel name of Vacuum to set. Must be one of the channels listed in manifold_parameters.ini.
  • state: A readable value interpreted as a boolean.

GETVAC

Format: GETVAC chan dest

  • chan: The channel name of Vacuum to get
  • dest: writable location to store that channel's state

Tooled Routines

Tooled Routines call functions that are defined by the "Tool" subclasses of the LabVIEW Gantry Class. To call these, the script must first execute the LOADTOOL command for the specific tool. Afterwards, the UNLOADTOOL command must be called.

LOADTOOL

"Loads" the specified tool. This means different things for different tools. For example, PICKER and GRABBER loading means moving the gantry to the tool rack and picking up that tool, while for CAMERA and SYRINGE it currently just does internal bookkeeping.

Format: LOADTOOL toolname

  • toolname: One of CAMERA, SYRINGE, PICKER, or GRABBER.

UNLOADTOOL

Format: UNLOADTOOL

Camera Tool

AUTOFOCUS

Format: AUTOFOCUS res range steps

  • res: Writable location to save the position of max focus in the specified range.
  • range: Size of window to search for maximum focus centered around the current position.
  • steps: The number of samples to take within range.

FINDFID

Format: FINDFID loc fidtype

  • loc: Location of the fiducial in gantry coordinates. If no fiducial was found, the result will be {-1,0,0,0}.
  • fidtype: Specify the type of fiducial you want to find. Needs to correspond to a section in fiducial_parameters.ini

Syringe Tool

POTLINE

Invokes the Syringe Tool potting routine. Must supply the start and end positions as well as the offset between the gantry camera and the needle tip. Currently, potting parameters (speed, tip-height, etc.) are read from the POTTING section of general_configuration.ini.

Format: POTLINE start end offset

  • start: 3D position of the start of the desired line of encapsulant
  • end: 3D position of the end of the desired line of encapsulant
  • offset: Calibrated 3d offset of the needle tip.

POTDOT

Format: POTLINE pos offset

  • start: 3D position of the desired dot of encapsulant
  • offset: Calibrated 3d offset of the needle tip.

Picker Tool

NOT IMPLEMENTED

Grabber Tool

NOT IMPLEMENTED

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