On 02/22/2014 05:33 AM, Greg Bentzinger wrote: > Yeah - I did some digging and that whole "L" word in a fixed cycle > dates back to the original NIST RS-274D-NGC. IMHO - Its a dinosaur > that should have died out. I consider it an accident waiting to be > activated by the user.
I agree that it is ancient and quite dangerous to use. However, since there is support for it, should it not work as advertised? The LinuxCNC docs say that it does one thing, but when I try the example, something different happens. Either the docu is wrong, or there is bitrot in the implementation. Even though it is ancient, it should then be fixed or removed. Having a wrong interpretation can lead to greater disaster. > One of the most powerful reasons to switch to LCNC is the faster > processing power and virtually unlimited program length. We have > O-loops and plenty of other tools to make good G-code without using > commands that are not so apparent in the actual actions they will > execute. I assume since it was all ready supported in the early > source code it has been kept as legacy support. I dare say most > modern machine controls do not support this without additional > verbose codes. Backwards compatibility is a good thing, which allows old code to run as expected. I agree that you should be severely disouraged from using it in the modern times. As you say, storage and computing power is no limitation nowadays. > As is, I try not to use fixed cycles in incremental (G91) mode if > possible. There can be enough confusion with the G98|G99 "R" and > initial points in Inc mode without other issues. Negative "R" values > are something to use with caution. The absolute mode (G90) cýclces do work as documented. They are actually useful. I also think that the relative mode cycles are useful, but they are a lot harder to grasp. That said, I implemented a couple of library calls for gcmc to emulate the canned cycles. There I just map it to G0/G1/G4 and perform the cycle programatically. Maybe I should not bother to implement the relative cousins and leave it at absolute canned- drill/drill_dwell/drill_peck cycles. You can always code your own version if you like. -- Greetings Bertho (disclaimers are disclaimed) ------------------------------------------------------------------------------ Managing the Performance of Cloud-Based Applications Take advantage of what the Cloud has to offer - Avoid Common Pitfalls. Read the Whitepaper. http://pubads.g.doubleclick.net/gampad/clk?id=121054471&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
