Here is my first guess at how I would do this: 1 -- First, I would "enhance" emc to support a new M code that took at least four arguments and returned at least one variable. Lets say M999 takes arguments N, X, Y, Z. N would be the name of an external program to run (say N=123, then ExtFn123 would be run). The other variables would be passed as arguments. Variable #999 (or whatever) would get the return value.
2 -- I would implement a new scan function that called M999 N=1 X=... Y=... Z=... ExtFn1 would take the X, Y, Z values and store them in some file. 3 -- I would implement a conversion function that converted the scan file into an easily (efficiently) read format. That might be M999 N=2 (ExtFn2). 4 -- I would implement an external function (ExtFn3) that takes the arguments X and Y and returned the Z value (in variable #999). This function would use the file format described above. All of this seems pretty straight forward. Ken Alan Battersby wrote: > Hi, > I am writing a gcode generator to create paths for ornamental turning > by simulating a rose engine. I have nearly completed the initial part > and am now looking at one of my further aims which is to allow me to > import a surface profile and then cut patterns following this profile. I > have the facility to import a probe file produced by emc which is all > working fine as is generating simple gcode, this is because I can access > the surface depth data directly in my program. > > My problem is that I thought I would use a bit more of emcs gcode > capability. So an alternative gcode generator (I can select which to > use) wraps every path as a gcode subroutine which is called from within > a gcode loop, looping for depth of cut etc, see attachment which was > generated without the surface following functionality. (I ultimately > intend to save each path in its own code file and call them externally > as required but not there yet). > > Now the subroutine case the decision about what depth to cut is taken as > the gcode is running rather than when the code is created. > By way of example > > In my program I use three bool flags; use_surface - true if using a > surface profile, follow_surface which is set true if the cut is to > follow the surface profile and finally a flag called > surface_pre_machined which is true if the surface profile has already > been cut before the path is cut. > > By way of explanation assume at a given point on the path the surface > depth is 10mm, the path depth is 6mm and the roughing cut depth is 2mm. > If both follow_surface and pre-machined flags are true then the first > cut depth should be 12mm and that I am cutting air for 10mm before I > reach the surface. So after a rapid move to the position at a safe > height I want a rapid move to depth 10mm then a linear feed move of 2mm. > So a total depth can be cut in three passes. (I have incorporated a > final finish cut pass but am ignoring that here). > If pre-machined is false then I will be cutting the whole of the 16mm in > 8 passes on the assumption that the surface profile will be cut later. > > However at each pass I dont want to move the cutter depth to cut into a > rising bit of surface profile deeper than necessary. So if at some point > the current cutter depth is say 10mm and the surface rises to 2mm I need > to raise the cutter to 8mm (2 + 6 path depth). Thus my need for depth > data at run time. > > I had thought that a clumsy way of overcoming this problem would be to > set up a current_surface_depth variable and assign it as I loop through > the points on the path in my program but I would rather access the data > in array form if possible any suggestions? > > Finally why am I doing it this way? Well I want to be able to take a > flat block of wood etc and cut my pattern as if it was on a domed > surface. Then fill the cuts with some coloured resin etc (easy to do on > a flat topped surface) and then cut the dome afterwards as a lid. > > Why am I bothering with subroutines and not just sticking to simple > gcode? Well 1) the files are much smaller and 2) I like programming it > was my job before I retired so this is also part of my hobby as much as > the actual machining. > > Last time I asked a question someone asked if I was releasing my code, > the answer is yes and I have started a blog describing the program at > http://wood at dyadica dot net/site/ obviously replace at with @ and > dot with . But I must emphasize that everything including the blog is > at weak alpha release. > > So can someone suggest the best way of achieving my aim? > Thanks and sorry this is so long > > Alan > > > > > > > ------------------------------------------------------------------------ > > ------------------------------------------------------------------------------ > Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day > trial. Simplify your report design, integration and deployment - and focus on > what you do best, core application coding. Discover what's new with > Crystal Reports now. http://p.sf.net/sfu/bobj-july > > > ------------------------------------------------------------------------ > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users -- Kenneth Lerman Mark Kenny Products Company, LLC 55 Main Street Newtown, CT 06470 888-ISO-SEVO 203-426-7166 ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
