differences between NC code & G code

I don't know what's the differences between NC code and G code, I think they are the same, but some files metion that they are quiet different. so is the NC code generated in CAD/CAM? but what about the G code?

G-code is a colloquial name for Numeric Code. However, there are many different styles of G-code/NC. EMC2 happens to use its own variant (officially titled rs274ngc) based upon the NIST standard. I might be screwing up the names and timeline here, but I believe the NIST standard was developed from rs274d, which originated in the 1980's. There are varying degrees of interoperability between styles, and most "professional" CAM programs have post-processors to convert between styles. The simplest styles of G-code programming is nothing more than a list of movement and coordinate commands. rs274ngc on the other hand, is structured like a high-level programming language and includes arithmetic functions, variables, conditions, loops, and sub-routines.

The online g-code reference manual for EMC is a great source for learning about G-code BTW. One of the best available.

Hope that helps a little.

thanks a lot, Rturner. This makes the concepts more clear to me.~ And one more question, does EMC2.3.3 is able to work with B-splines? For example, how can I display a curve in the preview plot??

Hi Vincent,
I have to claim ignorance on the subject of B-splines within EMC2. I *thought* that b-spline support is more-or-less still being tested in the development version, but I'm not certain since I use an older version and don't really work with splines anyways. I think there's a conversation about this very things somewhere else on the forums though.. Possibly one of the moderators would have an answer too. good luck!

vincent wrote:

thanks a lot, Rturner. This makes the concepts more clear to me.~ And one more question, does EMC2.3.3 is able to work with B-splines? For example, how can I display a curve in the preview plot??

I don't know what a B-spline is but if your asking about Nurbs only the development version 2.4 has that and it is AFAIK not tested.

John

Just so that we're on the same page: NURBS is a sub-set of B-splines.. With regards to CAD the two terms are often used inter-changeably... And yes, I did have to double-check this on wikipedia

If the spline is output by your CAD/CAM as a series of short line segments then EMC will handle it just fine for the most part. There can be cutter comp issues if going into an inside corner.

Also during actual cutting you will need to use the G64 p with a tolerance value or EMC may bog down.

when i try to run this code shows me an error:
G01 X10 Y10 Z10

why EMC can not excute this code?
is,nt there any way to excute it?

why EMC can not excute this code?

Did you give a feed rate? For example:

F100
G01 X10 Y10 Z10

or

G01 X10 Y10 Z10 F100