I am looking for information on the most popular [G/M] cnc file
layouts.

As some of you may remember I am writing a program to convert
HPGL files to cnc files. The reason for using HPGL rather than
dxf for input is that the HPGL files have the actual vectors for
text, including ttf, where the dxf files contain the text
strings.

I discovered a free GNU program called hp2xx that will take
regular HPGL and HPGL/2 files for input and generate an output
file using only PU [pen up], PD [pen down], and PA [plot
absolute] commands, with some other extraneous [for my purposes]
commands such as IN [initialize plotter]. This eliminates the
more problematic conversions such as converting AR [arc relative]
because of the difference in the way cnc controllers handle the
arc commands. The downside of this is that a single line for an
AR [arc relative] command is replaced with a huge number of short
absolute G1 moves.

My program called hpgl2cnc is nearing completion. Rather than
attempting to write a complete cnc program, this generates only
the G0/G1 codes that will need to be cut-n-pasted into a complete
program with headers to start the machine and footers to properly
shut it down. The program has the option of either metric or
inch code generation and will run in the "console" [dos box] of
windows xp and 2k. [I had to buy a new compiler (PowerBasic
CC4.01) to do this.]

HPGL plotter units are 1016 to the inch or 40 per m/m. Accuracy
will be 0.001 inch or 0.05 m/m. You will be able to set a
different plunge [z] and lateral [xy] feed rates. You will also
set a "clearance" above the part and a "plunge" distance into the
part in either inch or metric.

Specifically I need to know what is the most common/portable cnc
output file format suitable for cut-n-paste:

Line numbers? - how many places? Sequential or every 5 etc.

Include decimal points? If no decimal points what is assumed
accuracy?

Leading or trailing signs? -0.123 or 0.123- also do you want/need
+ signs?

Spaces between variable name and value, i.e. "X0.123" v "X 0.123"

Comment indicator? "%". " ' ", "*" or what?

== Is column alignment still important? If so what spacing? ==

== I am including range checking on the xy and z feed rates.
What is the min/max in inch and/or metric that you think you
would use? I am using IMP in the inch mode. What is the accepted
metric feed rate unit?

While HPGL2CNC is generally intended for plaques, I can see doing
2 dimensional contouring such as flat cams. With the ability in
most cad programs to turn layers on/off, some elaborate work
should be possible, with the manual insertion of G41/G42 codes
and T specifications.

Thanks for your advice.

I will post the compiled exe program and PowerBasic source on my
website and submit for inclusion on some of the other cnc sites
and the PowerBasic site. This will be freeware under the GPL.
If you would like a copy when it is completed please send me an
email. Most likely not the program to use for high volume
production, but may be just what you need for a one off plaque or
sign.

I'll start work on the 'C' axis version for engraving around a
cylinder when this one is up and running.

Uncle George

On Mon, 23 Jan 2006 14:54:34 -0600, F. George McDuffee
wrote:

I am looking for information on the most popular [G/M] cnc file
layouts.

It's indeed rather varied. Which is why we have postprocessors.
OTOH There is also the basic RS-274D standard which is a subset
of many sets of commnads these days.
See also the "Gerber" or RS-274D/X standard.
--
Cliff

George,

I have to aggree with Cliff. Much to varied. Might I suggest to
incorporate a NC formatter for basic things like you mentioned. You
don't need anything complex.

gary


F. George McDuffee wrote:
I am looking for information on the most popular [G/M] cnc file
layouts.

As some of you may remember I am writing a program to convert
HPGL files to cnc files. The reason for using HPGL rather than
dxf for input is that the HPGL files have the actual vectors for
text, including ttf, where the dxf files contain the text
strings.

I discovered a free GNU program called hp2xx that will take
regular HPGL and HPGL/2 files for input and generate an output
file using only PU [pen up], PD [pen down], and PA [plot
absolute] commands, with some other extraneous [for my purposes]
commands such as IN [initialize plotter]. This eliminates the
more problematic conversions such as converting AR [arc relative]
because of the difference in the way cnc controllers handle the
arc commands. The downside of this is that a single line for an
AR [arc relative] command is replaced with a huge number of short
absolute G1 moves.

My program called hpgl2cnc is nearing completion. Rather than
attempting to write a complete cnc program, this generates only
the G0/G1 codes that will need to be cut-n-pasted into a complete
program with headers to start the machine and footers to properly
shut it down. The program has the option of either metric or
inch code generation and will run in the "console" [dos box] of
windows xp and 2k. [I had to buy a new compiler (PowerBasic
CC4.01) to do this.]

HPGL plotter units are 1016 to the inch or 40 per m/m. Accuracy
will be 0.001 inch or 0.05 m/m. You will be able to set a
different plunge [z] and lateral [xy] feed rates. You will also
set a "clearance" above the part and a "plunge" distance into the
part in either inch or metric.

Specifically I need to know what is the most common/portable cnc
output file format suitable for cut-n-paste:

Line numbers? - how many places? Sequential or every 5 etc.

Include decimal points? If no decimal points what is assumed
accuracy?

Leading or trailing signs? -0.123 or 0.123- also do you want/need
+ signs?

Spaces between variable name and value, i.e. "X0.123" v "X 0.123"

Comment indicator? "%". " ' ", "*" or what?

== Is column alignment still important? If so what spacing? ==

== I am including range checking on the xy and z feed rates.
What is the min/max in inch and/or metric that you think you
would use? I am using IMP in the inch mode. What is the accepted
metric feed rate unit?

While HPGL2CNC is generally intended for plaques, I can see doing
2 dimensional contouring such as flat cams. With the ability in
most cad programs to turn layers on/off, some elaborate work
should be possible, with the manual insertion of G41/G42 codes
and T specifications.

Thanks for your advice.

I will post the compiled exe program and PowerBasic source on my
website and submit for inclusion on some of the other cnc sites
and the PowerBasic site. This will be freeware under the GPL.
If you would like a copy when it is completed please send me an
email. Most likely not the program to use for high volume
production, but may be just what you need for a one off plaque or
sign.

I'll start work on the 'C' axis version for engraving around a
cylinder when this one is up and running.

Uncle George

On 24 Jan 2006 09:00:30 -0800, wrote:

George,

I have to aggree with Cliff. Much to varied. Might I suggest to
incorporate a NC formatter for basic things like you mentioned. You
don't need anything complex.

IIRC Fanuc codes might be a bit non-standard (but very popular)
and comments "(" ")" *might* not be covered by the standard.
Perhaps worth considering.
--
Cliff

On Tue, 24 Jan 2006 05:45:51 -0500, Cliff
wrote:
On Mon, 23 Jan 2006 14:54:34 -0600, F. George McDuffee
wrote:
I am looking for information on the most popular [G/M] cnc file
layouts.
It's indeed rather varied. Which is why we have postprocessors.
OTOH There is also the basic RS-274D standard which is a subset
of many sets of commnads these days.
See also the "Gerber" or RS-274D/X standard.
=================================
Thanks to Cliff and every one else that replied directly [emails]
about the output file formats.

I have just about completed coding for the actual conversion of
the preprocessed ( using the gpl hp2xx ) HPGL and HPGL/2 files.

Your suggestion to operationally create a simple post appears to
be the best solution to the file format question.

Also I am doing range checking [min/max values] and would
appreciate advise on the following points, assuming you are using
small endmills for sign creation, etc.
(1) What are the min/max vertical feedrates and units that you
would ever use?
(2) What are the min/max horizontal feedrates and units you would
ever use?
(3) What is the min/max distance above the surface you would ever
use?
(4) What is the min/max plunge below the surface you would ever
use?

Items 1-4 will be input when you convert a processed hpgl file.

If you use a cad program, you can turn layers on/off before
plotting, so lettering in the bottom of a pocket is easy. Mirror
immage is also simple.

Units [mm/inch] will be determined in the configuration file.

A proforma output configuration file follows. Please review and
let me know what variables I have omitted, or other features you
would like.

=== possible configuration file for hpgl == G-CODE translator ==
*
* « CONFIGURATION FILE »
* for hpgl2cnc.exe -- a GPL public domain program.
*
* by default hpgl2cnc uses the hpgl2cnc.cfg config file.
*
* you can use different configuration files
* by specifying on the command line
* for example hpgl2cnc fanuc01.cfg or hpgl2cnc hurco.cfg
* these will need to be in the same directory as
* hpgl2cnc.exe unless you specify drive/directory.
*
* NOTE: hpgl2cnc generates only 2_1/2D moves, i.e. only 1 or 2
axis change in any one block.
*
* Lines begining with an astrisk are comments.
*
* All alpha values converted to upper case by the program.
*
* Settings shown are for an Emco F1 educational machining center,
and most and
* == MOST LIKELY NEED TO BE EDITED FOR YOUR CONTROLLER.==
*
* Be sure to use an editor program such as notepad or edit or
edlin that writes
* ==only plain ascii text== files with no formatting or other
control codes.
*
* Save a copy of this configuration file
* *BEFORE* you edit it as hpgl2cnc.org and set attributes to read
only.
*
* It is suggested that you complete the comment lines below
indicating
* what controller your configuration file suports when you modify
it.
* (and keep back-up versions)
* -- gmcd 07FEB2006 )
*
* edited configuration file data
* edited by: your name
* on: date
* for: your controller or machine name
*
* ==========================================
*
I , "unit output -- Inch/Imperial or Metric -- valid
values are I/M "
*
* ==========================================
*
% , "character used for controller comment line [ignore block]
9999 supresses comments"
*
* ==========================================
*
P , "decimal point character -- valid values are None, Point
for . and Comma for ,"
* NOTE: cannot input , directly
*
* ==========================================
*
3 , "number of digits in line number -- 0 suppresses [no N],
valid values are 0,3,4,5,6"
*
250 , "max number of lines you can cut-n-paste into your cnc
control program at one time"
* program will withdraw tool and home, write comment line, reset
line number counter to 25
* return tool to previous position and continue. Because
hpgl2cnc uses only straight line
* moves, cnc programs can be very large when arcs/curves are
involved.
*
* with 3 digit line numbers, max number of lines is 975 in any
one sub program
* with 4 diget line numbers, max number of lines is 9975 in any
one sub program
* with 5 digit line numbers, max number of lines is 99975 in any
one sub program
* with 6 diget line numbers, max number of lines is 999975 in any
one sub program
*
* ==========================================
*
1, " number of spaces between line number and 1st parameter? --
valid values are 0,1,2"
*
* =========================================
*
1 , "number of spaces between parameters? -- valid values are 0 ,
1, 2"
*
3 , "number of digits in XYZ cordinates -- valid values are
1,2,3,4,5,6"
*
4 , "number of decimals in XYZ cordinates -- valid values are
0,1,2,3,4,5,6"
*
Y , "leading zeros required for XYZ coordinates -- valid values
are Yes/No"
*
A , "does the minus sign [-] go before or after a negative
coordinate value -- Before /After
*
N , "include a plus sign [+] for positive coordinate values? --
Yes / No"
*
B , "Does the axis designator [XYZ] go Before or After the
axis vlaue?"
*
N , "space between XYZ axis designator and value? valid values --
Yes , No"
*
* ==========================================
*
A , "show all 3 coordinates or only changed coordinates in cnc
block -- All or Changed only"
*
* ==========================================
*
F , "feed rate designator -- generally F but any ascii string
255 characters or less"
*
2 , "number of digits in feed rates [F] -- valid values are
2,3,4,5"
*
1 , "number of decimal places in feed rate [F] -- valid values
are 0,1,2,3"
*
Y , "leading zeros required in feed rate? -- valid values Yes /
No"
*
N , "space required between F designator and feed rate value? --
valid entries are Yes / No"
*
B , "does the F go before or after the feed rate value? -- valid
entries are Before / After"
*
1 , "spaces between axis cordinate and feed rate -- valid vaues
are 0,1,2
*
E , "Feed rate specified for Each machining move or Modal --
valid values are E & M"
*
* ==========================================
*
G00 , "point-to-point straight line rapid traverse command --
generally G0 (G-zero)
* or G00 (g-zero-zero) but can be any ascii string 255
characters or less
*
*
G01 , "point-to-point straight line controlled feed command --
generally G1 G-one
* or G01 (G-zero-one) but can be any ascii string 255 characters
or less
*
* ==========================================
*
0.000 , "granularity or minimum move from X1,Y1,Z1 == X2,Y2,Z2"
*
* units are what ever you selected above Inch/Imperial or
Metric
* set to zero for best possible resolution. larger values will
produce smaller,
* faster running programs but detail and smoothness of curves may
be degraded.
* NOTE: HPGL plotter units are 40 per m/m or 1016 per inch, so
best possible
* accuracy is 0.001 inches or 0.025 m/m per axis.
*
* ========= NOTES =================
*
* NOTE: HPGL2CNC outputs 2_1/2D moves, i.e. only 2 axis moves in
any one block.
*
* Internally, HPGL2CNC uses PowerBasic long-word [unsigned long
integer]
* variables for the plotter value storage
* and converts to the desired inch/imperial or metric units using
double precesion variables
* before rounding to your indicated accuracy.
*
* PowerBasic's website is http://www.PowerBasic.com if you would
like more details
* Their manual is on-line.
*
* maximum unsigned long-word PowerBasic value is 4,294,967,295.
*
* At 1016 plotter units per inch this is a maximum size per side
of
* 4225361.511 inches, 352113.4592 feet or 66.68815516 miles.
*
* At 40 plotter units per m/m this is a maximum size per side of
107324182.4 m/m,
* 107324.1824 meters or 107.3241824 KM.
*
* ==========================================

On Tue, 14 Feb 2006 20:07:08 -0600, F. George McDuffee
wrote:

Also I am doing range checking [min/max values] and would
appreciate advise on the following points, assuming you are using
small endmills for sign creation, etc.
(1) What are the min/max vertical feedrates and units that you
would ever use?
(2) What are the min/max horizontal feedrates and units you would
ever use?
(3) What is the min/max distance above the surface you would ever
use?
(4) What is the min/max plunge below the surface you would ever
use?

Let the user input them & save them in a default file for the user.
Next time use the defaults with an option to change & save them.
--
Cliff

On Wed, 15 Feb 2006 10:11:20 -0500, Cliff
wrote:
On Tue, 14 Feb 2006 20:07:08 -0600, F. George McDuffee
wrote:
Also I am doing range checking [min/max values] and would
appreciate advise on the following points, assuming you are using
small endmills for sign creation, etc.
(1) What are the min/max vertical feedrates and units that you
would ever use?
(2) What are the min/max horizontal feedrates and units you would
ever use?
(3) What is the min/max distance above the surface you would ever
use?
(4) What is the min/max plunge below the surface you would ever
use?

Let the user input them & save them in a default file for the user.
Next time use the defaults with an option to change & save them.
==================
Sorry for the confusion in terminology. Range checking limits
the max/min feed rate that you can set. For example, 1 ipm to 20
ipm verticle feed rate. You can choose anything you wish in
between these values. As not everyone using this program will
have extensive experence, it is an effort to minimize tool
breakage.

Also I can see turning all the layers in your cad drawing off
except the pocket with crosshatching, plotting and macnining (key
is to use the offset command) the pocket with a larger tool /
feed rate, and then turning the pocket layer off and the
lettering layer on to plot the lettering at the bottom of the
pocket with a much smaller (possibly ball) end mill and and thus
a much smaller feed rate. This is where the clearence above the
surface for pen-up [G00] moves, and the maximum plunge below the
surface comes in.

With careful attention to tool offsets and using the offset
command in the cad program, you can get very good results in
milling cams with this. If anyone is interested I have a lisp
[lsp] program I wrote to generate cycloid curves that works with
autocad and intellicad.

Uncle George



Uncle George.

On Wed, 15 Feb 2006 13:21:55 -0600, F. George McDuffee
wrote:

On Wed, 15 Feb 2006 10:11:20 -0500, Cliff
wrote:
On Tue, 14 Feb 2006 20:07:08 -0600, F. George McDuffee
wrote:
Also I am doing range checking [min/max values] and would
appreciate advise on the following points, assuming you are using
small endmills for sign creation, etc.
(1) What are the min/max vertical feedrates and units that you
would ever use?
(2) What are the min/max horizontal feedrates and units you would
ever use?
(3) What is the min/max distance above the surface you would ever
use?
(4) What is the min/max plunge below the surface you would ever
use?

Let the user input them & save them in a default file for the user.
Next time use the defaults with an option to change & save them.
==================
Sorry for the confusion in terminology. Range checking limits
the max/min feed rate that you can set. For example, 1 ipm to 20
ipm verticle feed rate. You can choose anything you wish in
between these values.

First time the program runs:
Let the user input them & save them in a default file for the user.
Later times:
Next time use the defaults with an option to change & save them.
--
Cliff