.\"	$FabBSD$
.\"	Public domain
.\"
.Dd $Mdocdate: April 4 2009 $
.Dt NGC 1
.Os
.Sh NAME
.Nm ngc
.Nd NIST RS274/NGC numerical control code interpreter
.Sh SYNOPSIS
.Nm ngc
.Op Fl lmnvW
.Op Fl t Ar toolfile
.Op Ar file ...
.Sh DESCRIPTION
The
.Nm
command executes a machine tool program written in RS274/NGC code
(NIST
.Dq Next Generation Controller
Version 3).
Unless the simulation
.Pf ( Fl n )
option is used,
.Nm
performs machine actions directly.
.Pp
Code may be spread across multiple files.
The program
.Em main
(which must be the first program passed to
.Nm )
and subroutines are separated by lines containing a single
.Sq %
character.
Subroutines are identified by "O1234" (or ":1234") lines.
.Pp
.Nm
verifies input programs for errors before they are executed.
However, fatal hardware conditions (e.g., raised
.Xr estop 4
events,
.Xr atc 4
failures) will cause
.Nm
to interrupt execution and exit with an error code.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl l
Execute program(s) in
.Em lathe
(turning) mode.
.It Fl m
Execute program(s) in
.Em milling
mode.
This is the default.
.It Fl n
Run the program in simulation mode (do not perform actual machining operations).
This is useful for verifying the syntax of a program.
.It Fl t
Read the tool sheet from
.Ar toolfile .
The tool sheet is a CSV file containing information about the tools referenced
by the
.Em T
instructions in the program; see the
.Dq TOOL FILES
section for more information.
.It Fl v
Enable verbose operation (default).
.It Fl W
Enable extra warnings.
.El
.Sh TOOL FILES
The
.Nm
tool file format is a simple CSV-style database with fields:
.Bl -tag -width "Tool Length Offset "
.It Name
The unsigned integer identifying the tool, which will be referenced by
.Em T
commands.
.It Tool Length Offset
A real number normally representing the length of the tool as it extends
from the chuck.
.It Diameter
Effective diameter of the tool.
This value is only applicable to tool paths programmed with radius compensation.
If the tool path programmed corresponds to the edge of the part, this specifies
the
.Em measured diameter
of the tool.
Alternatively, if the tool path represents the motion of a cutter of nominal
diameter, this field should describe the small
.Em difference
with respect to the nominal diameter.
.It Carousel slot
When an
.Xr atc 4
is used to interface with a tool carousel, this field should specify the pocket
(slot) number of the tool.
.It Comment
An arbitrary string description of the tool.
.El
.Sh ENVIRONMENT
.Bl -tag -width UNITS
.It Ev UNITS
Set to
.Sq metric
or
.Sq inch .
Defaults to
.Sq metric .
.El
.Sh SEE ALSO
.Xr atc 4 ,
.Xr cnc 3 ,
.Xr cncmove 3
.Rs
.%A Thomas R. Kramer
.%A Frederick M. Proctor
.%A Elena Messina
.%D August 2000
.%T "The NIST RS274NGC Interpreter - Version 3"
.%C Gaithersburg, Maryland
.%I National Institute of Standards and Technology
.%R NISTIR 6556
.Re
.Sh HISTORY
The
.Nm
command first appeared in FabBSD 1.0.